Merge branch 'master' into index-lifecycle

CONTRIBUTING.md

@@ -209,6 +209,14 @@ Before submitting your changes, run the test suite to make sure that nothing is
 ./gradlew check
 ```
 
+If your changes affect only the documentation, run:
+
+```sh
+./gradlew -p docs check
+```
+For more information about testing code examples in the documentation, see 
+https://github.com/elastic/elasticsearch/blob/master/docs/README.asciidoc
+
 ### Project layout
 
 This repository is split into many top level directories. The most important

client/benchmark/src/main/java/org/elasticsearch/client/benchmark/transport/TransportClientBenchmark.java

@@ -79,7 +79,7 @@ public final class TransportClientBenchmark extends AbstractBenchmark<TransportC
 
         @Override
         public boolean bulkIndex(List<String> bulkData) {
-            NoopBulkRequestBuilder builder = NoopBulkAction.INSTANCE.newRequestBuilder(client);
+            NoopBulkRequestBuilder builder = new NoopBulkRequestBuilder(client,NoopBulkAction.INSTANCE);
             for (String bulkItem : bulkData) {
                 builder.add(new IndexRequest(indexName, typeName).source(bulkItem.getBytes(StandardCharsets.UTF_8), XContentType.JSON));
             }
@@ -108,7 +108,7 @@ public final class TransportClientBenchmark extends AbstractBenchmark<TransportC
         @Override
         public boolean search(String source) {
             final SearchResponse response;
-            NoopSearchRequestBuilder builder = NoopSearchAction.INSTANCE.newRequestBuilder(client);
+            NoopSearchRequestBuilder builder = new NoopSearchRequestBuilder(client, NoopSearchAction.INSTANCE);
             try {
                 builder.setIndices(indexName);
                 builder.setQuery(QueryBuilders.wrapperQuery(source));

client/client-benchmark-noop-api-plugin/src/main/java/org/elasticsearch/plugin/noop/action/bulk/NoopBulkAction.java

@@ -21,9 +21,8 @@ package org.elasticsearch.plugin.noop.action.bulk;
 import org.elasticsearch.action.Action;
 import org.elasticsearch.action.bulk.BulkRequest;
 import org.elasticsearch.action.bulk.BulkResponse;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public class NoopBulkAction extends Action<BulkRequest, BulkResponse, NoopBulkRequestBuilder> {
+public class NoopBulkAction extends Action<BulkRequest, BulkResponse> {
     public static final String NAME = "mock:data/write/bulk";
 
     public static final NoopBulkAction INSTANCE = new NoopBulkAction();
@@ -32,11 +31,6 @@ public class NoopBulkAction extends Action<BulkRequest, BulkResponse, NoopBulkRe
         super(NAME);
     }
 
-    @Override
-    public NoopBulkRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new NoopBulkRequestBuilder(client, this);
-    }
-
     @Override
     public BulkResponse newResponse() {
         return new BulkResponse(null, 0);

client/client-benchmark-noop-api-plugin/src/main/java/org/elasticsearch/plugin/noop/action/bulk/NoopBulkRequestBuilder.java

@@ -35,7 +35,7 @@ import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.XContentType;
 
-public class NoopBulkRequestBuilder extends ActionRequestBuilder<BulkRequest, BulkResponse, NoopBulkRequestBuilder>
+public class NoopBulkRequestBuilder extends ActionRequestBuilder<BulkRequest, BulkResponse>
         implements WriteRequestBuilder<NoopBulkRequestBuilder> {
 
     public NoopBulkRequestBuilder(ElasticsearchClient client, NoopBulkAction action) {

client/client-benchmark-noop-api-plugin/src/main/java/org/elasticsearch/plugin/noop/action/search/NoopSearchAction.java

@@ -21,9 +21,8 @@ package org.elasticsearch.plugin.noop.action.search;
 import org.elasticsearch.action.Action;
 import org.elasticsearch.action.search.SearchRequest;
 import org.elasticsearch.action.search.SearchResponse;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public class NoopSearchAction extends Action<SearchRequest, SearchResponse, NoopSearchRequestBuilder> {
+public class NoopSearchAction extends Action<SearchRequest, SearchResponse> {
     public static final NoopSearchAction INSTANCE = new NoopSearchAction();
     public static final String NAME = "mock:data/read/search";
 
@@ -31,11 +30,6 @@ public class NoopSearchAction extends Action<SearchRequest, SearchResponse, Noop
         super(NAME);
     }
 
-    @Override
-    public NoopSearchRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new NoopSearchRequestBuilder(client, this);
-    }
-
     @Override
     public SearchResponse newResponse() {
         return new SearchResponse();

client/client-benchmark-noop-api-plugin/src/main/java/org/elasticsearch/plugin/noop/action/search/NoopSearchRequestBuilder.java

@@ -42,7 +42,7 @@ import org.elasticsearch.search.suggest.SuggestBuilder;
 import java.util.Arrays;
 import java.util.List;
 
-public class NoopSearchRequestBuilder extends ActionRequestBuilder<SearchRequest, SearchResponse, NoopSearchRequestBuilder> {
+public class NoopSearchRequestBuilder extends ActionRequestBuilder<SearchRequest, SearchResponse> {
 
     public NoopSearchRequestBuilder(ElasticsearchClient client, NoopSearchAction action) {
         super(client, action, new SearchRequest());

client/rest-high-level/src/main/java/org/elasticsearch/client/ClusterClient.java

@@ -23,6 +23,8 @@ import org.apache.http.Header;
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
 import org.elasticsearch.action.admin.cluster.settings.ClusterUpdateSettingsResponse;
+import org.elasticsearch.action.ingest.GetPipelineRequest;
+import org.elasticsearch.action.ingest.GetPipelineResponse;
 import org.elasticsearch.action.ingest.PutPipelineRequest;
 import org.elasticsearch.action.ingest.PutPipelineResponse;
 
@@ -87,4 +89,26 @@ public final class ClusterClient {
         restHighLevelClient.performRequestAsyncAndParseEntity( request, RequestConverters::putPipeline,
             PutPipelineResponse::fromXContent, listener, emptySet(), headers);
     }
+
+    /**
+     * Get an existing pipeline
+     * <p>
+     * See
+     * <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/get-pipeline-api.html"> Get Pipeline API on elastic.co</a>
+     */
+    public GetPipelineResponse getPipeline(GetPipelineRequest request, Header... headers) throws IOException {
+        return restHighLevelClient.performRequestAndParseEntity( request, RequestConverters::getPipeline,
+            GetPipelineResponse::fromXContent, emptySet(), headers);
+    }
+
+    /**
+     * Asynchronously get an existing pipeline
+     * <p>
+     * See
+     * <a href="https://www.elastic.co/guide/en/elasticsearch/reference/master/get-pipeline-api.html"> Get Pipeline API on elastic.co</a>
+     */
+    public void getPipelineAsync(GetPipelineRequest request, ActionListener<GetPipelineResponse> listener, Header... headers) {
+        restHighLevelClient.performRequestAsyncAndParseEntity( request, RequestConverters::getPipeline,
+            GetPipelineResponse::fromXContent, listener, emptySet(), headers);
+    }
 }

client/rest-high-level/src/main/java/org/elasticsearch/client/RequestConverters.java

@@ -61,6 +61,7 @@ import org.elasticsearch.action.get.GetRequest;
 import org.elasticsearch.action.get.MultiGetRequest;
 import org.elasticsearch.action.index.IndexRequest;
 import org.elasticsearch.action.ingest.PutPipelineRequest;
+import org.elasticsearch.action.ingest.GetPipelineRequest;
 import org.elasticsearch.action.search.ClearScrollRequest;
 import org.elasticsearch.action.search.MultiSearchRequest;
 import org.elasticsearch.action.search.SearchRequest;
@@ -620,6 +621,18 @@ final class RequestConverters {
         return request;
     }
 
+    static Request getPipeline(GetPipelineRequest getPipelineRequest) {
+        String endpoint = new EndpointBuilder()
+            .addPathPartAsIs("_ingest/pipeline")
+            .addCommaSeparatedPathParts(getPipelineRequest.getIds())
+            .build();
+        Request request = new Request(HttpGet.METHOD_NAME, endpoint);
+
+        Params parameters = new Params(request);
+        parameters.withMasterTimeout(getPipelineRequest.masterNodeTimeout());
+        return request;
+    }
+
     static Request putPipeline(PutPipelineRequest putPipelineRequest) throws IOException {
         String endpoint = new EndpointBuilder()
             .addPathPartAsIs("_ingest/pipeline")

client/rest-high-level/src/main/java/org/elasticsearch/client/RestHighLevelClient.java

@@ -279,6 +279,17 @@ public class RestHighLevelClient implements Closeable {
      *
      * See <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-bulk.html">Bulk API on elastic.co</a>
      */
+    public final BulkResponse bulk(BulkRequest bulkRequest, RequestOptions options) throws IOException {
+        return performRequestAndParseEntity(bulkRequest, RequestConverters::bulk, options, BulkResponse::fromXContent, emptySet());
+    }
+
+    /**
+     * Executes a bulk request using the Bulk API
+     *
+     * See <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-bulk.html">Bulk API on elastic.co</a>
+     * @deprecated Prefer {@link #bulk(BulkRequest, RequestOptions)}
+     */
+    @Deprecated
     public final BulkResponse bulk(BulkRequest bulkRequest, Header... headers) throws IOException {
         return performRequestAndParseEntity(bulkRequest, RequestConverters::bulk, BulkResponse::fromXContent, emptySet(), headers);
     }
@@ -288,6 +299,17 @@ public class RestHighLevelClient implements Closeable {
      *
      * See <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-bulk.html">Bulk API on elastic.co</a>
      */
+    public final void bulkAsync(BulkRequest bulkRequest, RequestOptions options, ActionListener<BulkResponse> listener) {
+        performRequestAsyncAndParseEntity(bulkRequest, RequestConverters::bulk, options, BulkResponse::fromXContent, listener, emptySet());
+    }
+
+    /**
+     * Asynchronously executes a bulk request using the Bulk API
+     *
+     * See <a href="https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-bulk.html">Bulk API on elastic.co</a>
+     * @deprecated Prefer {@link #bulkAsync(BulkRequest, RequestOptions, ActionListener)}
+     */
+    @Deprecated
     public final void bulkAsync(BulkRequest bulkRequest, ActionListener<BulkResponse> listener, Header... headers) {
         performRequestAsyncAndParseEntity(bulkRequest, RequestConverters::bulk, BulkResponse::fromXContent, listener, emptySet(), headers);
     }
@@ -584,6 +606,7 @@ public class RestHighLevelClient implements Closeable {
             FieldCapabilitiesResponse::fromXContent, listener, emptySet(), headers);
     }
 
+    @Deprecated
     protected final <Req extends ActionRequest, Resp> Resp performRequestAndParseEntity(Req request,
                                                                             CheckedFunction<Req, Request, IOException> requestConverter,
                                                                             CheckedFunction<XContentParser, Resp, IOException> entityParser,
@@ -591,16 +614,34 @@ public class RestHighLevelClient implements Closeable {
         return performRequest(request, requestConverter, (response) -> parseEntity(response.getEntity(), entityParser), ignores, headers);
     }
 
+    protected final <Req extends ActionRequest, Resp> Resp performRequestAndParseEntity(Req request,
+                                                                            CheckedFunction<Req, Request, IOException> requestConverter,
+                                                                            RequestOptions options,
+                                                                            CheckedFunction<XContentParser, Resp, IOException> entityParser,
+                                                                            Set<Integer> ignores) throws IOException {
+        return performRequest(request, requestConverter, options,
+                response -> parseEntity(response.getEntity(), entityParser), ignores);
+    }
+
+    @Deprecated
     protected final <Req extends ActionRequest, Resp> Resp performRequest(Req request,
                                                           CheckedFunction<Req, Request, IOException> requestConverter,
                                                           CheckedFunction<Response, Resp, IOException> responseConverter,
                                                           Set<Integer> ignores, Header... headers) throws IOException {
+        return performRequest(request, requestConverter, optionsForHeaders(headers), responseConverter, ignores);
+    }
+
+    protected final <Req extends ActionRequest, Resp> Resp performRequest(Req request,
+                                                          CheckedFunction<Req, Request, IOException> requestConverter,
+                                                          RequestOptions options,
+                                                          CheckedFunction<Response, Resp, IOException> responseConverter,
+                                                          Set<Integer> ignores) throws IOException {
         ActionRequestValidationException validationException = request.validate();
         if (validationException != null) {
             throw validationException;
         }
         Request req = requestConverter.apply(request);
-        addHeaders(req, headers);
+        req.setOptions(options);
         Response response;
         try {
             response = client.performRequest(req);
@@ -626,6 +667,7 @@ public class RestHighLevelClient implements Closeable {
         }
     }
 
+    @Deprecated
     protected final <Req extends ActionRequest, Resp> void performRequestAsyncAndParseEntity(Req request,
                                                                  CheckedFunction<Req, Request, IOException> requestConverter,
                                                                  CheckedFunction<XContentParser, Resp, IOException> entityParser,
@@ -634,10 +676,28 @@ public class RestHighLevelClient implements Closeable {
                 listener, ignores, headers);
     }
 
+    protected final <Req extends ActionRequest, Resp> void performRequestAsyncAndParseEntity(Req request,
+                                                                 CheckedFunction<Req, Request, IOException> requestConverter,
+                                                                 RequestOptions options,
+                                                                 CheckedFunction<XContentParser, Resp, IOException> entityParser,
+                                                                 ActionListener<Resp> listener, Set<Integer> ignores) {
+        performRequestAsync(request, requestConverter, options,
+                response -> parseEntity(response.getEntity(), entityParser), listener, ignores);
+    }
+
+    @Deprecated
     protected final <Req extends ActionRequest, Resp> void performRequestAsync(Req request,
                                                                CheckedFunction<Req, Request, IOException> requestConverter,
                                                                CheckedFunction<Response, Resp, IOException> responseConverter,
                                                                ActionListener<Resp> listener, Set<Integer> ignores, Header... headers) {
+        performRequestAsync(request, requestConverter, optionsForHeaders(headers), responseConverter, listener, ignores);
+    }
+
+    protected final <Req extends ActionRequest, Resp> void performRequestAsync(Req request,
+                                                               CheckedFunction<Req, Request, IOException> requestConverter,
+                                                               RequestOptions options,
+                                                               CheckedFunction<Response, Resp, IOException> responseConverter,
+                                                               ActionListener<Resp> listener, Set<Integer> ignores) {
         ActionRequestValidationException validationException = request.validate();
         if (validationException != null) {
             listener.onFailure(validationException);
@@ -650,19 +710,12 @@ public class RestHighLevelClient implements Closeable {
             listener.onFailure(e);
             return;
         }
-        addHeaders(req, headers);
+        req.setOptions(options);
 
         ResponseListener responseListener = wrapResponseListener(responseConverter, listener, ignores);
         client.performRequestAsync(req, responseListener);
     }
 
-    private static void addHeaders(Request request, Header... headers) {
-        Objects.requireNonNull(headers, "headers cannot be null");
-        for (Header header : headers) {
-            request.addHeader(header.getName(), header.getValue());
-        }
-    }
-
     final <Resp> ResponseListener wrapResponseListener(CheckedFunction<Response, Resp, IOException> responseConverter,
                                                         ActionListener<Resp> actionListener, Set<Integer> ignores) {
         return new ResponseListener() {
@@ -746,6 +799,15 @@ public class RestHighLevelClient implements Closeable {
         }
     }
 
+    private static RequestOptions optionsForHeaders(Header[] headers) {
+        RequestOptions.Builder options = RequestOptions.DEFAULT.toBuilder();
+        for (Header header : headers) {
+            Objects.requireNonNull(header, "header cannot be null");
+            options.addHeader(header.getName(), header.getValue());
+        }
+        return options.build();
+    }
+
     static boolean convertExistsResponse(Response response) {
         return response.getStatusLine().getStatusCode() == 200;
     }

client/rest-high-level/src/test/java/org/elasticsearch/client/ClusterClientIT.java

@@ -22,6 +22,8 @@ package org.elasticsearch.client;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
 import org.elasticsearch.action.admin.cluster.settings.ClusterUpdateSettingsResponse;
+import org.elasticsearch.action.ingest.GetPipelineRequest;
+import org.elasticsearch.action.ingest.GetPipelineResponse;
 import org.elasticsearch.action.ingest.PutPipelineRequest;
 import org.elasticsearch.action.ingest.PutPipelineResponse;
 import org.elasticsearch.cluster.routing.allocation.decider.EnableAllocationDecider;
@@ -32,7 +34,7 @@ import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.common.xcontent.support.XContentMapValues;
 import org.elasticsearch.indices.recovery.RecoverySettings;
-import org.elasticsearch.ingest.Pipeline;
+import org.elasticsearch.ingest.PipelineConfiguration;
 import org.elasticsearch.rest.RestStatus;
 
 import java.io.IOException;
@@ -113,31 +115,7 @@ public class ClusterClientIT extends ESRestHighLevelClientTestCase {
 
     public void testPutPipeline() throws IOException {
         String id = "some_pipeline_id";
-        XContentType xContentType = randomFrom(XContentType.values());
+        XContentBuilder pipelineBuilder = buildRandomXContentPipeline();
-        XContentBuilder pipelineBuilder = XContentBuilder.builder(xContentType.xContent());
-        pipelineBuilder.startObject();
-        {
-            pipelineBuilder.field(Pipeline.DESCRIPTION_KEY, "some random set of processors");
-            pipelineBuilder.startArray(Pipeline.PROCESSORS_KEY);
-            {
-                pipelineBuilder.startObject().startObject("set");
-                {
-                    pipelineBuilder
-                        .field("field", "foo")
-                        .field("value", "bar");
-                }
-                pipelineBuilder.endObject().endObject();
-                pipelineBuilder.startObject().startObject("convert");
-                {
-                    pipelineBuilder
-                        .field("field", "rank")
-                        .field("type", "integer");
-                }
-                pipelineBuilder.endObject().endObject();
-            }
-            pipelineBuilder.endArray();
-        }
-        pipelineBuilder.endObject();
         PutPipelineRequest request = new PutPipelineRequest(
             id,
             BytesReference.bytes(pipelineBuilder),
@@ -147,4 +125,27 @@ public class ClusterClientIT extends ESRestHighLevelClientTestCase {
             execute(request, highLevelClient().cluster()::putPipeline, highLevelClient().cluster()::putPipelineAsync);
         assertTrue(putPipelineResponse.isAcknowledged());
     }
+
+    public void testGetPipeline() throws IOException {
+        String id = "some_pipeline_id";
+        XContentBuilder pipelineBuilder = buildRandomXContentPipeline();
+        {
+            PutPipelineRequest request = new PutPipelineRequest(
+                id,
+                BytesReference.bytes(pipelineBuilder),
+                pipelineBuilder.contentType()
+            );
+            createPipeline(request);
+        }
+
+        GetPipelineRequest request = new GetPipelineRequest(id);
+
+        GetPipelineResponse response =
+            execute(request, highLevelClient().cluster()::getPipeline, highLevelClient().cluster()::getPipelineAsync);
+        assertTrue(response.isFound());
+        assertEquals(response.pipelines().get(0).getId(), id);
+        PipelineConfiguration expectedConfig =
+            new PipelineConfiguration(id, BytesReference.bytes(pipelineBuilder), pipelineBuilder.contentType());
+        assertEquals(expectedConfig.getConfigAsMap(), response.pipelines().get(0).getConfigAsMap());
+    }
 }

client/rest-high-level/src/test/java/org/elasticsearch/client/CustomRestHighLevelClientTests.java

@@ -26,7 +26,6 @@ import org.apache.http.RequestLine;
 import org.apache.http.client.methods.HttpGet;
 import org.apache.http.entity.ByteArrayEntity;
 import org.apache.http.entity.ContentType;
-import org.apache.http.message.BasicHeader;
 import org.apache.http.message.BasicRequestLine;
 import org.apache.http.message.BasicStatusLine;
 import org.apache.lucene.util.BytesRef;
@@ -48,11 +47,13 @@ import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.util.Arrays;
 import java.util.Collections;
-import java.util.List;
+import java.util.Set;
+import java.util.TreeSet;
 import java.util.stream.Collectors;
 
 import static java.util.Collections.emptySet;
-import static org.hamcrest.Matchers.containsInAnyOrder;
+import static org.hamcrest.Matchers.contains;
+import static org.hamcrest.Matchers.hasSize;
 import static org.mockito.Matchers.any;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.mock;
@@ -73,12 +74,12 @@ public class CustomRestHighLevelClientTests extends ESTestCase {
             final RestClient restClient = mock(RestClient.class);
             restHighLevelClient = new CustomRestClient(restClient);
 
-            doAnswer(inv -> mockPerformRequest(((Request) inv.getArguments()[0]).getHeaders().iterator().next()))
+            doAnswer(inv -> mockPerformRequest((Request) inv.getArguments()[0]))
                     .when(restClient)
                     .performRequest(any(Request.class));
 
             doAnswer(inv -> mockPerformRequestAsync(
-                        ((Request) inv.getArguments()[0]).getHeaders().iterator().next(),
+                        ((Request) inv.getArguments()[0]),
                         (ResponseListener) inv.getArguments()[1]))
                     .when(restClient)
                     .performRequestAsync(any(Request.class), any(ResponseListener.class));
@@ -87,26 +88,32 @@ public class CustomRestHighLevelClientTests extends ESTestCase {
 
     public void testCustomEndpoint() throws IOException {
         final MainRequest request = new MainRequest();
-        final Header header = new BasicHeader("node_name", randomAlphaOfLengthBetween(1, 10));
+        String nodeName = randomAlphaOfLengthBetween(1, 10);
 
-        MainResponse response = restHighLevelClient.custom(request, header);
+        MainResponse response = restHighLevelClient.custom(request, optionsForNodeName(nodeName));
-        assertEquals(header.getValue(), response.getNodeName());
+        assertEquals(nodeName, response.getNodeName());
 
-        response = restHighLevelClient.customAndParse(request, header);
+        response = restHighLevelClient.customAndParse(request, optionsForNodeName(nodeName));
-        assertEquals(header.getValue(), response.getNodeName());
+        assertEquals(nodeName, response.getNodeName());
     }
 
     public void testCustomEndpointAsync() throws Exception {
         final MainRequest request = new MainRequest();
-        final Header header = new BasicHeader("node_name", randomAlphaOfLengthBetween(1, 10));
+        String nodeName = randomAlphaOfLengthBetween(1, 10);
 
         PlainActionFuture<MainResponse> future = PlainActionFuture.newFuture();
-        restHighLevelClient.customAsync(request, future, header);
+        restHighLevelClient.customAsync(request, optionsForNodeName(nodeName), future);
-        assertEquals(header.getValue(), future.get().getNodeName());
+        assertEquals(nodeName, future.get().getNodeName());
 
         future = PlainActionFuture.newFuture();
-        restHighLevelClient.customAndParseAsync(request, future, header);
+        restHighLevelClient.customAndParseAsync(request, optionsForNodeName(nodeName), future);
-        assertEquals(header.getValue(), future.get().getNodeName());
+        assertEquals(nodeName, future.get().getNodeName());
+    }
+
+    private static RequestOptions optionsForNodeName(String nodeName) {
+        RequestOptions.Builder options = RequestOptions.DEFAULT.toBuilder();
+        options.addHeader("node_name", nodeName);
+        return options.build();
     }
 
     /**
@@ -115,27 +122,27 @@ public class CustomRestHighLevelClientTests extends ESTestCase {
      */
     @SuppressForbidden(reason = "We're forced to uses Class#getDeclaredMethods() here because this test checks protected methods")
     public void testMethodsVisibility() throws ClassNotFoundException {
-        final String[] methodNames = new String[]{"performRequest",
+        final String[] methodNames = new String[]{"parseEntity",
-                                                  "performRequestAsync",
+                                                  "parseResponseException",
+                                                  "performRequest",
                                                   "performRequestAndParseEntity",
-                                                  "performRequestAsyncAndParseEntity",
+                                                  "performRequestAsync",
-                                                  "parseEntity",
+                                                  "performRequestAsyncAndParseEntity"};
-                                                  "parseResponseException"};
 
-        final List<String> protectedMethods =  Arrays.stream(RestHighLevelClient.class.getDeclaredMethods())
+        final Set<String> protectedMethods =  Arrays.stream(RestHighLevelClient.class.getDeclaredMethods())
                                                      .filter(method -> Modifier.isProtected(method.getModifiers()))
                                                      .map(Method::getName)
-                                                     .collect(Collectors.toList());
+                                                     .collect(Collectors.toCollection(TreeSet::new));
 
-        assertThat(protectedMethods, containsInAnyOrder(methodNames));
+        assertThat(protectedMethods, contains(methodNames));
     }
 
     /**
-     * Mocks the asynchronous request execution by calling the {@link #mockPerformRequest(Header)} method.
+     * Mocks the asynchronous request execution by calling the {@link #mockPerformRequest(Request)} method.
      */
-    private Void mockPerformRequestAsync(Header httpHeader, ResponseListener responseListener) {
+    private Void mockPerformRequestAsync(Request request, ResponseListener responseListener) {
         try {
-            responseListener.onSuccess(mockPerformRequest(httpHeader));
+            responseListener.onSuccess(mockPerformRequest(request));
         } catch (IOException e) {
             responseListener.onFailure(e);
         }
@@ -145,7 +152,9 @@ public class CustomRestHighLevelClientTests extends ESTestCase {
     /**
      * Mocks the synchronous request execution like if it was executed by Elasticsearch.
      */
-    private Response mockPerformRequest(Header httpHeader) throws IOException {
+    private Response mockPerformRequest(Request request) throws IOException {
+        assertThat(request.getOptions().getHeaders(), hasSize(1));
+        Header httpHeader = request.getOptions().getHeaders().get(0);
         final Response mockResponse = mock(Response.class);
         when(mockResponse.getHost()).thenReturn(new HttpHost("localhost", 9200));
 
@@ -171,20 +180,20 @@ public class CustomRestHighLevelClientTests extends ESTestCase {
             super(restClient, RestClient::close, Collections.emptyList());
         }
 
-        MainResponse custom(MainRequest mainRequest, Header... headers) throws IOException {
+        MainResponse custom(MainRequest mainRequest, RequestOptions options) throws IOException {
-            return performRequest(mainRequest, this::toRequest, this::toResponse, emptySet(), headers);
+            return performRequest(mainRequest, this::toRequest, options, this::toResponse, emptySet());
         }
 
-        MainResponse customAndParse(MainRequest mainRequest, Header... headers) throws IOException {
+        MainResponse customAndParse(MainRequest mainRequest, RequestOptions options) throws IOException {
-            return performRequestAndParseEntity(mainRequest, this::toRequest, MainResponse::fromXContent, emptySet(), headers);
+            return performRequestAndParseEntity(mainRequest, this::toRequest, options, MainResponse::fromXContent, emptySet());
         }
 
-        void customAsync(MainRequest mainRequest, ActionListener<MainResponse> listener, Header... headers) {
+        void customAsync(MainRequest mainRequest, RequestOptions options, ActionListener<MainResponse> listener) {
-            performRequestAsync(mainRequest, this::toRequest, this::toResponse, listener, emptySet(), headers);
+            performRequestAsync(mainRequest, this::toRequest, options, this::toResponse, listener, emptySet());
         }
 
-        void customAndParseAsync(MainRequest mainRequest, ActionListener<MainResponse> listener, Header... headers) {
+        void customAndParseAsync(MainRequest mainRequest, RequestOptions options, ActionListener<MainResponse> listener) {
-            performRequestAsyncAndParseEntity(mainRequest, this::toRequest, MainResponse::fromXContent, listener, emptySet(), headers);
+            performRequestAsyncAndParseEntity(mainRequest, this::toRequest, options, MainResponse::fromXContent, listener, emptySet());
         }
 
         Request toRequest(MainRequest mainRequest) throws IOException {

client/rest-high-level/src/test/java/org/elasticsearch/client/ESRestHighLevelClientTestCase.java

@@ -21,7 +21,12 @@ package org.elasticsearch.client;
 
 import org.apache.http.Header;
 import org.elasticsearch.action.ActionListener;
+import org.elasticsearch.action.ingest.PutPipelineRequest;
 import org.elasticsearch.action.support.PlainActionFuture;
+import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentType;
+import org.elasticsearch.ingest.Pipeline;
 import org.elasticsearch.test.rest.ESRestTestCase;
 import org.junit.AfterClass;
 import org.junit.Before;
@@ -80,4 +85,42 @@ public abstract class ESRestHighLevelClientTestCase extends ESRestTestCase {
             super(restClient, (client) -> {}, Collections.emptyList());
         }
     }
+
+    protected static XContentBuilder buildRandomXContentPipeline() throws IOException {
+        XContentType xContentType = randomFrom(XContentType.values());
+        XContentBuilder pipelineBuilder = XContentBuilder.builder(xContentType.xContent());
+        pipelineBuilder.startObject();
+        {
+            pipelineBuilder.field(Pipeline.DESCRIPTION_KEY, "some random set of processors");
+            pipelineBuilder.startArray(Pipeline.PROCESSORS_KEY);
+            {
+                pipelineBuilder.startObject().startObject("set");
+                {
+                    pipelineBuilder
+                        .field("field", "foo")
+                        .field("value", "bar");
+                }
+                pipelineBuilder.endObject().endObject();
+                pipelineBuilder.startObject().startObject("convert");
+                {
+                    pipelineBuilder
+                        .field("field", "rank")
+                        .field("type", "integer");
+                }
+                pipelineBuilder.endObject().endObject();
+            }
+            pipelineBuilder.endArray();
+        }
+        pipelineBuilder.endObject();
+        return pipelineBuilder;
+    }
+
+    protected static void createPipeline(String pipelineId) throws IOException {
+        XContentBuilder builder = buildRandomXContentPipeline();
+        createPipeline(new PutPipelineRequest(pipelineId, BytesReference.bytes(builder), builder.contentType()));
+    }
+
+    protected static void createPipeline(PutPipelineRequest putPipelineRequest) throws IOException {
+        assertOK(client().performRequest(RequestConverters.putPipeline(putPipelineRequest)));
+    }
 }

client/rest-high-level/src/test/java/org/elasticsearch/client/RequestConvertersTests.java

@@ -63,6 +63,7 @@ import org.elasticsearch.action.fieldcaps.FieldCapabilitiesRequest;
 import org.elasticsearch.action.get.GetRequest;
 import org.elasticsearch.action.get.MultiGetRequest;
 import org.elasticsearch.action.index.IndexRequest;
+import org.elasticsearch.action.ingest.GetPipelineRequest;
 import org.elasticsearch.action.ingest.PutPipelineRequest;
 import org.elasticsearch.action.search.ClearScrollRequest;
 import org.elasticsearch.action.search.MultiSearchRequest;
@@ -1450,6 +1451,20 @@ public class RequestConvertersTests extends ESTestCase {
         assertEquals(expectedParams, expectedRequest.getParameters());
     }
 
+    public void testGetPipeline() {
+        String pipelineId = "some_pipeline_id";
+        Map<String, String> expectedParams = new HashMap<>();
+        GetPipelineRequest request = new GetPipelineRequest("some_pipeline_id");
+        setRandomMasterTimeout(request, expectedParams);
+        Request expectedRequest = RequestConverters.getPipeline(request);
+        StringJoiner endpoint = new StringJoiner("/", "/", "");
+        endpoint.add("_ingest/pipeline");
+        endpoint.add(pipelineId);
+        assertEquals(endpoint.toString(), expectedRequest.getEndpoint());
+        assertEquals(HttpGet.METHOD_NAME, expectedRequest.getMethod());
+        assertEquals(expectedParams, expectedRequest.getParameters());
+    }
+
     public void testRollover() throws IOException {
         RolloverRequest rolloverRequest = new RolloverRequest(randomAlphaOfLengthBetween(3, 10),
                 randomBoolean() ? null : randomAlphaOfLengthBetween(3, 10));

client/rest-high-level/src/test/java/org/elasticsearch/client/documentation/ClusterClientDocumentationIT.java

@@ -23,6 +23,8 @@ import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.action.LatchedActionListener;
 import org.elasticsearch.action.admin.cluster.settings.ClusterUpdateSettingsRequest;
 import org.elasticsearch.action.admin.cluster.settings.ClusterUpdateSettingsResponse;
+import org.elasticsearch.action.ingest.GetPipelineRequest;
+import org.elasticsearch.action.ingest.GetPipelineResponse;
 import org.elasticsearch.action.ingest.PutPipelineRequest;
 import org.elasticsearch.action.ingest.PutPipelineResponse;
 import org.elasticsearch.client.ESRestHighLevelClientTestCase;
@@ -34,11 +36,13 @@ import org.elasticsearch.common.unit.ByteSizeUnit;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.indices.recovery.RecoverySettings;
+import org.elasticsearch.ingest.PipelineConfiguration;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.List;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 
@@ -257,4 +261,74 @@ public class ClusterClientDocumentationIT extends ESRestHighLevelClientTestCase
             assertTrue(latch.await(30L, TimeUnit.SECONDS));
         }
     }
+
+    public void testGetPipeline() throws IOException {
+        RestHighLevelClient client = highLevelClient();
+
+        {
+            createPipeline("my-pipeline-id");
+        }
+
+        {
+            // tag::get-pipeline-request
+            GetPipelineRequest request = new GetPipelineRequest("my-pipeline-id"); // <1>
+            // end::get-pipeline-request
+
+            // tag::get-pipeline-request-masterTimeout
+            request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); // <1>
+            request.masterNodeTimeout("1m"); // <2>
+            // end::get-pipeline-request-masterTimeout
+
+            // tag::get-pipeline-execute
+            GetPipelineResponse response = client.cluster().getPipeline(request); // <1>
+            // end::get-pipeline-execute
+
+            // tag::get-pipeline-response
+            boolean successful = response.isFound(); // <1>
+            List<PipelineConfiguration> pipelines = response.pipelines(); // <2>
+            for(PipelineConfiguration pipeline: pipelines) {
+                Map<String, Object> config = pipeline.getConfigAsMap(); // <3>
+            }
+            // end::get-pipeline-response
+
+            assertTrue(successful);
+        }
+    }
+
+    public void testGetPipelineAsync() throws Exception {
+        RestHighLevelClient client = highLevelClient();
+
+        {
+            createPipeline("my-pipeline-id");
+        }
+
+        {
+            GetPipelineRequest request = new GetPipelineRequest("my-pipeline-id");
+
+            // tag::get-pipeline-execute-listener
+            ActionListener<GetPipelineResponse> listener =
+                new ActionListener<GetPipelineResponse>() {
+                    @Override
+                    public void onResponse(GetPipelineResponse response) {
+                        // <1>
+                    }
+
+                    @Override
+                    public void onFailure(Exception e) {
+                        // <2>
+                    }
+                };
+            // end::get-pipeline-execute-listener
+
+            // Replace the empty listener by a blocking listener in test
+            final CountDownLatch latch = new CountDownLatch(1);
+            listener = new LatchedActionListener<>(listener, latch);
+
+            // tag::get-pipeline-execute-async
+            client.cluster().getPipelineAsync(request, listener); // <1>
+            // end::get-pipeline-execute-async
+
+            assertTrue(latch.await(30L, TimeUnit.SECONDS));
+        }
+    }
 }

client/rest/src/main/java/org/elasticsearch/client/Request.java

@@ -19,17 +19,11 @@
 
 package org.elasticsearch.client;
 
-import org.apache.http.Header;
 import org.apache.http.HttpEntity;
 import org.apache.http.entity.ContentType;
-import org.apache.http.message.BasicHeader;
 import org.apache.http.nio.entity.NStringEntity;
-import org.apache.http.nio.protocol.HttpAsyncResponseConsumer;
 
-import java.util.ArrayList;
-import java.util.Collections;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 
@@ -42,11 +36,9 @@ public final class Request {
     private final String method;
     private final String endpoint;
     private final Map<String, String> parameters = new HashMap<>();
-    private final List<Header> headers = new ArrayList<>();
 
     private HttpEntity entity;
-    private HttpAsyncResponseConsumerFactory httpAsyncResponseConsumerFactory =
+    private RequestOptions options = RequestOptions.DEFAULT;
-            HttpAsyncResponseConsumerFactory.DEFAULT;
 
     /**
      * Create the {@linkplain Request}.
@@ -127,40 +119,29 @@ public final class Request {
     }
 
     /**
-     * Add the provided header to the request.
+     * Set the portion of an HTTP request to Elasticsearch that can be
+     * manipulated without changing Elasticsearch's behavior.
      */
-    public void addHeader(String name, String value) {
+    public void setOptions(RequestOptions options) {
-        Objects.requireNonNull(name, "header name cannot be null");
+        Objects.requireNonNull(options, "options cannot be null");
-        Objects.requireNonNull(value, "header value cannot be null");
+        this.options = options;
-        this.headers.add(new ReqHeader(name, value));
     }
 
     /**
-     * Headers to attach to the request.
+     * Set the portion of an HTTP request to Elasticsearch that can be
+     * manipulated without changing Elasticsearch's behavior.
      */
-    List<Header> getHeaders() {
+    public void setOptions(RequestOptions.Builder options) {
-        return Collections.unmodifiableList(headers);
+        Objects.requireNonNull(options, "options cannot be null");
+        this.options = options.build();
     }
 
     /**
-     * set the {@link HttpAsyncResponseConsumerFactory} used to create one
+     * Get the portion of an HTTP request to Elasticsearch that can be
-     * {@link HttpAsyncResponseConsumer} callback per retry. Controls how the
+     * manipulated without changing Elasticsearch's behavior.
-     * response body gets streamed from a non-blocking HTTP connection on the
-     * client side.
      */
-    public void setHttpAsyncResponseConsumerFactory(HttpAsyncResponseConsumerFactory httpAsyncResponseConsumerFactory) {
+    public RequestOptions getOptions() {
-        this.httpAsyncResponseConsumerFactory =
+        return options;
-                Objects.requireNonNull(httpAsyncResponseConsumerFactory, "httpAsyncResponseConsumerFactory cannot be null");
-    }
-
-    /**
-     * The {@link HttpAsyncResponseConsumerFactory} used to create one
-     * {@link HttpAsyncResponseConsumer} callback per retry. Controls how the
-     * response body gets streamed from a non-blocking HTTP connection on the
-     * client side.
-     */
-    public HttpAsyncResponseConsumerFactory getHttpAsyncResponseConsumerFactory() {
-        return httpAsyncResponseConsumerFactory;
     }
 
     @Override
@@ -175,18 +156,7 @@ public final class Request {
         if (entity != null) {
             b.append(", entity=").append(entity);
         }
-        if (headers.size() > 0) {
+        b.append(", options=").append(options);
-            b.append(", headers=");
-            for (int h = 0; h < headers.size(); h++) {
-                if (h != 0) {
-                    b.append(',');
-                }
-                b.append(headers.get(h).toString());
-            }
-        }
-        if (httpAsyncResponseConsumerFactory != HttpAsyncResponseConsumerFactory.DEFAULT) {
-            b.append(", consumerFactory=").append(httpAsyncResponseConsumerFactory);
-        }
         return b.append('}').toString();
     }
 
@@ -204,40 +174,11 @@ public final class Request {
                 && endpoint.equals(other.endpoint)
                 && parameters.equals(other.parameters)
                 && Objects.equals(entity, other.entity)
-                && headers.equals(other.headers)
+                && options.equals(other.options);
-                && httpAsyncResponseConsumerFactory.equals(other.httpAsyncResponseConsumerFactory);
     }
 
     @Override
     public int hashCode() {
-        return Objects.hash(method, endpoint, parameters, entity, headers.hashCode(), httpAsyncResponseConsumerFactory);
+        return Objects.hash(method, endpoint, parameters, entity, options);
-    }
-
-    /**
-     * Custom implementation of {@link BasicHeader} that overrides equals and hashCode.
-     */
-    static final class ReqHeader extends BasicHeader {
-
-        ReqHeader(String name, String value) {
-            super(name, value);
-        }
-
-        @Override
-        public boolean equals(Object other) {
-            if (this == other) {
-                return true;
-            }
-            if (other instanceof ReqHeader) {
-                Header otherHeader = (Header) other;
-                return Objects.equals(getName(), otherHeader.getName()) &&
-                        Objects.equals(getValue(), otherHeader.getValue());
-            }
-            return false;
-        }
-
-        @Override
-        public int hashCode() {
-            return Objects.hash(getName(), getValue());
-        }
     }
 }

client/rest/src/main/java/org/elasticsearch/client/RequestOptions.java

@@ -0,0 +1,175 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.client;
+
+import org.apache.http.message.BasicHeader;
+import org.apache.http.Header;
+import org.apache.http.nio.protocol.HttpAsyncResponseConsumer;
+import org.elasticsearch.client.HttpAsyncResponseConsumerFactory.HeapBufferedResponseConsumerFactory;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.Objects;
+
+
+import java.util.ArrayList;
+
+/**
+ * The portion of an HTTP request to Elasticsearch that can be
+ * manipulated without changing Elasticsearch's behavior.
+ */
+public final class RequestOptions {
+    public static final RequestOptions DEFAULT = new Builder(
+        Collections.<Header>emptyList(), HeapBufferedResponseConsumerFactory.DEFAULT).build();
+
+    private final List<Header> headers;
+    private final HttpAsyncResponseConsumerFactory httpAsyncResponseConsumerFactory;
+
+    private RequestOptions(Builder builder) {
+        this.headers = Collections.unmodifiableList(new ArrayList<>(builder.headers));
+        this.httpAsyncResponseConsumerFactory = builder.httpAsyncResponseConsumerFactory;
+    }
+
+    public Builder toBuilder() {
+        Builder builder = new Builder(headers, httpAsyncResponseConsumerFactory);
+        return builder;
+    }
+
+    /**
+     * Headers to attach to the request.
+     */
+    public List<Header> getHeaders() {
+        return headers;
+    }
+
+    /**
+     * The {@link HttpAsyncResponseConsumerFactory} used to create one
+     * {@link HttpAsyncResponseConsumer} callback per retry. Controls how the
+     * response body gets streamed from a non-blocking HTTP connection on the
+     * client side.
+     */
+    public HttpAsyncResponseConsumerFactory getHttpAsyncResponseConsumerFactory() {
+        return httpAsyncResponseConsumerFactory;
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder b = new StringBuilder();
+        b.append("RequestOptions{");
+        if (headers.size() > 0) {
+            b.append(", headers=");
+            for (int h = 0; h < headers.size(); h++) {
+                if (h != 0) {
+                    b.append(',');
+                }
+                b.append(headers.get(h).toString());
+            }
+        }
+        if (httpAsyncResponseConsumerFactory != HttpAsyncResponseConsumerFactory.DEFAULT) {
+            b.append(", consumerFactory=").append(httpAsyncResponseConsumerFactory);
+        }
+        return b.append('}').toString();
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == null || (obj.getClass() != getClass())) {
+            return false;
+        }
+        if (obj == this) {
+            return true;
+        }
+
+        RequestOptions other = (RequestOptions) obj;
+        return headers.equals(other.headers)
+                && httpAsyncResponseConsumerFactory.equals(other.httpAsyncResponseConsumerFactory);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(headers, httpAsyncResponseConsumerFactory);
+    }
+
+    public static class Builder {
+        private final List<Header> headers;
+        private HttpAsyncResponseConsumerFactory httpAsyncResponseConsumerFactory;
+
+        private Builder(List<Header> headers, HttpAsyncResponseConsumerFactory httpAsyncResponseConsumerFactory) {
+            this.headers = new ArrayList<>(headers);
+            this.httpAsyncResponseConsumerFactory = httpAsyncResponseConsumerFactory;
+        }
+
+        /**
+         * Build the {@linkplain RequestOptions}.
+         */
+        public RequestOptions build() {
+            return new RequestOptions(this);
+        }
+
+        /**
+         * Add the provided header to the request.
+         */
+        public void addHeader(String name, String value) {
+            Objects.requireNonNull(name, "header name cannot be null");
+            Objects.requireNonNull(value, "header value cannot be null");
+            this.headers.add(new ReqHeader(name, value));
+        }
+
+        /**
+         * set the {@link HttpAsyncResponseConsumerFactory} used to create one
+         * {@link HttpAsyncResponseConsumer} callback per retry. Controls how the
+         * response body gets streamed from a non-blocking HTTP connection on the
+         * client side.
+         */
+        public void setHttpAsyncResponseConsumerFactory(HttpAsyncResponseConsumerFactory httpAsyncResponseConsumerFactory) {
+            this.httpAsyncResponseConsumerFactory =
+                    Objects.requireNonNull(httpAsyncResponseConsumerFactory, "httpAsyncResponseConsumerFactory cannot be null");
+        }
+    }
+
+    /**
+     * Custom implementation of {@link BasicHeader} that overrides equals and
+     * hashCode so it is easier to test equality of {@link RequestOptions}.
+     */
+    static final class ReqHeader extends BasicHeader {
+
+        ReqHeader(String name, String value) {
+            super(name, value);
+        }
+
+        @Override
+        public boolean equals(Object other) {
+            if (this == other) {
+                return true;
+            }
+            if (other instanceof ReqHeader) {
+                Header otherHeader = (Header) other;
+                return Objects.equals(getName(), otherHeader.getName()) &&
+                        Objects.equals(getValue(), otherHeader.getValue());
+            }
+            return false;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(getName(), getValue());
+        }
+    }
+}

client/rest/src/main/java/org/elasticsearch/client/RestClient.java

@@ -61,6 +61,7 @@ import java.util.Comparator;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
+import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
@@ -132,7 +133,7 @@ public class RestClient implements Closeable {
         if (hosts == null || hosts.length == 0) {
             throw new IllegalArgumentException("hosts must not be null nor empty");
         }
-        Set<HttpHost> httpHosts = new HashSet<>();
+        Set<HttpHost> httpHosts = new LinkedHashSet<>();
         AuthCache authCache = new BasicAuthCache();
         for (HttpHost host : hosts) {
             Objects.requireNonNull(host, "host cannot be null");
@@ -143,6 +144,13 @@ public class RestClient implements Closeable {
         this.blacklist.clear();
     }
 
+    /**
+     * Returns the configured hosts
+     */
+    public List<HttpHost> getHosts() {
+        return new ArrayList<>(hostTuple.hosts);
+    }
+
     /**
      * Sends a request to the Elasticsearch cluster that the client points to.
      * Blocks until the request is completed and returns its response or fails
@@ -304,8 +312,7 @@ public class RestClient implements Closeable {
         Request request = new Request(method, endpoint);
         addParameters(request, params);
         request.setEntity(entity);
-        request.setHttpAsyncResponseConsumerFactory(httpAsyncResponseConsumerFactory);
+        setOptions(request, httpAsyncResponseConsumerFactory, headers);
-        addHeaders(request, headers);
         return performRequest(request);
     }
 
@@ -419,8 +426,7 @@ public class RestClient implements Closeable {
             request = new Request(method, endpoint);
             addParameters(request, params);
             request.setEntity(entity);
-            request.setHttpAsyncResponseConsumerFactory(httpAsyncResponseConsumerFactory);
+            setOptions(request, httpAsyncResponseConsumerFactory, headers);
-            addHeaders(request, headers);
         } catch (Exception e) {
             responseListener.onFailure(e);
             return;
@@ -457,11 +463,11 @@ public class RestClient implements Closeable {
         }
         URI uri = buildUri(pathPrefix, request.getEndpoint(), requestParams);
         HttpRequestBase httpRequest = createHttpRequest(request.getMethod(), uri, request.getEntity());
-        setHeaders(httpRequest, request.getHeaders());
+        setHeaders(httpRequest, request.getOptions().getHeaders());
         FailureTrackingResponseListener failureTrackingResponseListener = new FailureTrackingResponseListener(listener);
         long startTime = System.nanoTime();
         performRequestAsync(startTime, nextHost(), httpRequest, ignoreErrorCodes,
-                request.getHttpAsyncResponseConsumerFactory(), failureTrackingResponseListener);
+                request.getOptions().getHttpAsyncResponseConsumerFactory(), failureTrackingResponseListener);
     }
 
     private void performRequestAsync(final long startTime, final HostTuple<Iterator<HttpHost>> hostTuple, final HttpRequestBase request,
@@ -883,11 +889,24 @@ public class RestClient implements Closeable {
      */
     @Deprecated
     private static void addHeaders(Request request, Header... headers) {
+        setOptions(request, RequestOptions.DEFAULT.getHttpAsyncResponseConsumerFactory(), headers);
+    }
+
+    /**
+     * Add all headers from the provided varargs argument to a {@link Request}. This only exists
+     * to support methods that exist for backwards compatibility.
+     */
+    @Deprecated
+    private static void setOptions(Request request, HttpAsyncResponseConsumerFactory httpAsyncResponseConsumerFactory,
+            Header... headers) {
         Objects.requireNonNull(headers, "headers cannot be null");
+        RequestOptions.Builder options = request.getOptions().toBuilder();
         for (Header header : headers) {
             Objects.requireNonNull(header, "header cannot be null");
-            request.addHeader(header.getName(), header.getValue());
+            options.addHeader(header.getName(), header.getValue());
         }
+        options.setHttpAsyncResponseConsumerFactory(httpAsyncResponseConsumerFactory);
+        request.setOptions(options);
     }
 
     /**

client/rest/src/test/java/org/elasticsearch/client/RequestOptionsTests.java

@@ -0,0 +1,142 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.client;
+
+import org.apache.http.Header;
+import org.elasticsearch.client.HttpAsyncResponseConsumerFactory.HeapBufferedResponseConsumerFactory;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.fail;
+import static org.mockito.Mockito.mock;
+
+public class RequestOptionsTests extends RestClientTestCase {
+    public void testDefault() {
+        assertEquals(Collections.<Header>emptyList(), RequestOptions.DEFAULT.getHeaders());
+        assertEquals(HttpAsyncResponseConsumerFactory.DEFAULT, RequestOptions.DEFAULT.getHttpAsyncResponseConsumerFactory());
+        assertEquals(RequestOptions.DEFAULT, RequestOptions.DEFAULT.toBuilder().build());
+    }
+
+    public void testAddHeader() {
+        try {
+            randomBuilder().addHeader(null, randomAsciiLettersOfLengthBetween(3, 10));
+            fail("expected failure");
+        } catch (NullPointerException e) {
+            assertEquals("header name cannot be null", e.getMessage());
+        }
+
+        try {
+            randomBuilder().addHeader(randomAsciiLettersOfLengthBetween(3, 10), null);
+            fail("expected failure");
+        } catch (NullPointerException e) {
+            assertEquals("header value cannot be null", e.getMessage());
+        }
+
+        RequestOptions.Builder builder = RequestOptions.DEFAULT.toBuilder();
+        int numHeaders = between(0, 5);
+        List<Header> headers = new ArrayList<>();
+        for (int i = 0; i < numHeaders; i++) {
+            Header header = new RequestOptions.ReqHeader(randomAsciiAlphanumOfLengthBetween(5, 10), randomAsciiAlphanumOfLength(3));
+            headers.add(header);
+            builder.addHeader(header.getName(), header.getValue());
+        }
+        RequestOptions options = builder.build();
+        assertEquals(headers, options.getHeaders());
+
+        try {
+            options.getHeaders().add(
+                    new RequestOptions.ReqHeader(randomAsciiAlphanumOfLengthBetween(5, 10), randomAsciiAlphanumOfLength(3)));
+            fail("expected failure");
+        } catch (UnsupportedOperationException e) {
+            assertNull(e.getMessage());
+        }
+    }
+
+    public void testSetHttpAsyncResponseConsumerFactory() {
+        try {
+            RequestOptions.DEFAULT.toBuilder().setHttpAsyncResponseConsumerFactory(null);
+            fail("expected failure");
+        } catch (NullPointerException e) {
+            assertEquals("httpAsyncResponseConsumerFactory cannot be null", e.getMessage());
+        }
+
+        HttpAsyncResponseConsumerFactory factory = mock(HttpAsyncResponseConsumerFactory.class);
+        RequestOptions.Builder builder = RequestOptions.DEFAULT.toBuilder();
+        builder.setHttpAsyncResponseConsumerFactory(factory);
+        RequestOptions options = builder.build();
+        assertSame(factory, options.getHttpAsyncResponseConsumerFactory());
+    }
+
+    public void testEqualsAndHashCode() {
+        RequestOptions request = randomBuilder().build();
+        assertEquals(request, request);
+
+        RequestOptions copy = copy(request);
+        assertEquals(request, copy);
+        assertEquals(copy, request);
+        assertEquals(request.hashCode(), copy.hashCode());
+
+        RequestOptions mutant = mutate(request);
+        assertNotEquals(request, mutant);
+        assertNotEquals(mutant, request);
+    }
+
+    static RequestOptions.Builder randomBuilder() {
+        RequestOptions.Builder builder = RequestOptions.DEFAULT.toBuilder();
+
+        if (randomBoolean()) {
+            int headerCount = between(1, 5);
+            for (int i = 0; i < headerCount; i++) {
+                builder.addHeader(randomAsciiAlphanumOfLength(3), randomAsciiAlphanumOfLength(3));
+            }
+        }
+
+        if (randomBoolean()) {
+            builder.setHttpAsyncResponseConsumerFactory(new HeapBufferedResponseConsumerFactory(1));
+        }
+
+        return builder;
+    }
+
+    private static RequestOptions copy(RequestOptions options) {
+        return options.toBuilder().build();
+    }
+
+    private static RequestOptions mutate(RequestOptions options) {
+        RequestOptions.Builder mutant = options.toBuilder();
+        int mutationType = between(0, 1);
+        switch (mutationType) {
+        case 0:
+            mutant.addHeader("extra", "m");
+            return mutant.build();
+        case 1:
+            mutant.setHttpAsyncResponseConsumerFactory(new HeapBufferedResponseConsumerFactory(5));
+            return mutant.build();
+        default:
+            throw new UnsupportedOperationException("Unknown mutation type [" + mutationType + "]");
+        }
+    }
+}

client/rest/src/test/java/org/elasticsearch/client/RequestTests.java

@@ -37,6 +37,7 @@ import java.util.Map;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
 import static org.junit.Assert.fail;
 
 public class RequestTests extends RestClientTestCase {
@@ -127,33 +128,33 @@ public class RequestTests extends RestClientTestCase {
         assertEquals(json, new String(os.toByteArray(), ContentType.APPLICATION_JSON.getCharset()));
     }
 
-    public void testAddHeader() {
+    public void testSetOptions() {
         final String method = randomFrom(new String[] {"GET", "PUT", "POST", "HEAD", "DELETE"});
         final String endpoint = randomAsciiLettersOfLengthBetween(1, 10);
         Request request = new Request(method, endpoint);
 
         try {
-            request.addHeader(null, randomAsciiLettersOfLengthBetween(3, 10));
+            request.setOptions((RequestOptions) null);
             fail("expected failure");
         } catch (NullPointerException e) {
-            assertEquals("header name cannot be null", e.getMessage());
+            assertEquals("options cannot be null", e.getMessage());
         }
 
         try {
-            request.addHeader(randomAsciiLettersOfLengthBetween(3, 10), null);
+            request.setOptions((RequestOptions.Builder) null);
             fail("expected failure");
         } catch (NullPointerException e) {
-            assertEquals("header value cannot be null", e.getMessage());
+            assertEquals("options cannot be null", e.getMessage());
         }
 
-        int numHeaders = between(0, 5);
+        RequestOptions.Builder builder = RequestOptionsTests.randomBuilder();
-        List<Header> headers = new ArrayList<>();
+        request.setOptions(builder);
-        for (int i = 0; i < numHeaders; i++) {
+        assertEquals(builder.build(), request.getOptions());
-            Header header = new Request.ReqHeader(randomAsciiAlphanumOfLengthBetween(5, 10), randomAsciiAlphanumOfLength(3));
+
-            headers.add(header);
+        builder = RequestOptionsTests.randomBuilder();
-            request.addHeader(header.getName(), header.getValue());
+        RequestOptions options = builder.build();
-        }
+        request.setOptions(options);
-        assertEquals(headers, new ArrayList<>(request.getHeaders()));
+        assertSame(options, request.getOptions());
     }
 
     public void testEqualsAndHashCode() {
@@ -193,14 +194,9 @@ public class RequestTests extends RestClientTestCase {
         }
 
         if (randomBoolean()) {
-            int headerCount = between(1, 5);
+            RequestOptions.Builder options = request.getOptions().toBuilder();
-            for (int i = 0; i < headerCount; i++) {
+            options.setHttpAsyncResponseConsumerFactory(new HeapBufferedResponseConsumerFactory(1));
-                request.addHeader(randomAsciiAlphanumOfLength(3), randomAsciiAlphanumOfLength(3));
+            request.setOptions(options);
-            }
-        }
-
-        if (randomBoolean()) {
-            request.setHttpAsyncResponseConsumerFactory(new HeapBufferedResponseConsumerFactory(1));
         }
 
         return request;
@@ -222,7 +218,7 @@ public class RequestTests extends RestClientTestCase {
             return mutant;
         }
         Request mutant = copy(request);
-        int mutationType = between(0, 3);
+        int mutationType = between(0, 2);
         switch (mutationType) {
         case 0:
             mutant.addParameter(randomAsciiAlphanumOfLength(mutant.getParameters().size() + 4), "extra");
@@ -231,10 +227,9 @@ public class RequestTests extends RestClientTestCase {
             mutant.setJsonEntity("mutant"); // randomRequest can't produce this value
             return mutant;
         case 2:
-            mutant.addHeader("extra", "m");
+            RequestOptions.Builder options = mutant.getOptions().toBuilder();
-            return mutant;
+            options.addHeader("extra", "m");
-        case 3:
+            mutant.setOptions(options);
-            mutant.setHttpAsyncResponseConsumerFactory(new HeapBufferedResponseConsumerFactory(5));
             return mutant;
         default:
             throw new UnsupportedOperationException("Unknown mutation type [" + mutationType + "]");
@@ -246,9 +241,6 @@ public class RequestTests extends RestClientTestCase {
             to.addParameter(param.getKey(), param.getValue());
         }
         to.setEntity(from.getEntity());
-        for (Header header : from.getHeaders()) {
+        to.setOptions(from.getOptions());
-            to.addHeader(header.getName(), header.getValue());
-        }
-        to.setHttpAsyncResponseConsumerFactory(from.getHttpAsyncResponseConsumerFactory());
     }
 }

client/rest/src/test/java/org/elasticsearch/client/RestClientSingleHostIntegTests.java

@@ -378,9 +378,11 @@ public class RestClientSingleHostIntegTests extends RestClientTestCase {
         String requestBody = "{ \"field\": \"value\" }";
         Request request = new Request(method, "/" + statusCode);
         request.setJsonEntity(requestBody);
+        RequestOptions.Builder options = request.getOptions().toBuilder();
         for (Header header : headers) {
-            request.addHeader(header.getName(), header.getValue());
+            options.addHeader(header.getName(), header.getValue());
         }
+        request.setOptions(options);
         Response esResponse;
         try {
             esResponse = restClient.performRequest(request);

client/rest/src/test/java/org/elasticsearch/client/RestClientSingleHostTests.java

@@ -362,9 +362,11 @@ public class RestClientSingleHostTests extends RestClientTestCase {
             final Header[] requestHeaders = RestClientTestUtil.randomHeaders(getRandom(), "Header");
             final int statusCode = randomStatusCode(getRandom());
             Request request = new Request(method, "/" + statusCode);
+            RequestOptions.Builder options = request.getOptions().toBuilder();
             for (Header requestHeader : requestHeaders) {
-                request.addHeader(requestHeader.getName(), requestHeader.getValue());
+                options.addHeader(requestHeader.getName(), requestHeader.getValue());
             }
+            request.setOptions(options);
             Response esResponse;
             try {
                 esResponse = restClient.performRequest(request);
@@ -438,11 +440,13 @@ public class RestClientSingleHostTests extends RestClientTestCase {
         final Set<String> uniqueNames = new HashSet<>();
         if (randomBoolean()) {
             Header[] headers = RestClientTestUtil.randomHeaders(getRandom(), "Header");
+            RequestOptions.Builder options = request.getOptions().toBuilder();
             for (Header header : headers) {
-                request.addHeader(header.getName(), header.getValue());
+                options.addHeader(header.getName(), header.getValue());
-                expectedRequest.addHeader(new Request.ReqHeader(header.getName(), header.getValue()));
+                expectedRequest.addHeader(new RequestOptions.ReqHeader(header.getName(), header.getValue()));
                 uniqueNames.add(header.getName());
             }
+            request.setOptions(options);
         }
         for (Header defaultHeader : defaultHeaders) {
             // request level headers override default headers

client/rest/src/test/java/org/elasticsearch/client/RestClientTests.java

@@ -25,6 +25,7 @@ import org.apache.http.impl.nio.client.CloseableHttpAsyncClient;
 
 import java.io.IOException;
 import java.net.URI;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
@@ -251,6 +252,37 @@ public class RestClientTests extends RestClientTestCase {
         }
     }
 
+    public void testSetHostsPreservesOrdering() throws Exception {
+        try (RestClient restClient = createRestClient()) {
+            HttpHost[] hosts = randomHosts();
+            restClient.setHosts(hosts);
+            assertEquals(Arrays.asList(hosts), restClient.getHosts());
+        }
+    }
+
+    private static HttpHost[] randomHosts() {
+        int numHosts = randomIntBetween(1, 10);
+        HttpHost[] hosts = new HttpHost[numHosts];
+        for (int i = 0; i < hosts.length; i++) {
+            hosts[i] = new HttpHost("host-" + i, 9200);
+        }
+        return hosts;
+    }
+
+    public void testSetHostsDuplicatedHosts() throws Exception {
+        try (RestClient restClient = createRestClient()) {
+            int numHosts = randomIntBetween(1, 10);
+            HttpHost[] hosts = new HttpHost[numHosts];
+            HttpHost host = new HttpHost("host", 9200);
+            for (int i = 0; i < hosts.length; i++) {
+                hosts[i] = host;
+            }
+            restClient.setHosts(hosts);
+            assertEquals(1, restClient.getHosts().size());
+            assertEquals(host, restClient.getHosts().get(0));
+        }
+    }
+
     /**
      * @deprecated will remove method in 7.0 but needs tests until then. Replaced by {@link RequestTests#testConstructor()}.
      */

client/rest/src/test/java/org/elasticsearch/client/documentation/RestClientDocumentation.java

@@ -38,6 +38,7 @@ import org.apache.http.ssl.SSLContexts;
 import org.apache.http.util.EntityUtils;
 import org.elasticsearch.client.HttpAsyncResponseConsumerFactory;
 import org.elasticsearch.client.Request;
+import org.elasticsearch.client.RequestOptions;
 import org.elasticsearch.client.Response;
 import org.elasticsearch.client.ResponseListener;
 import org.elasticsearch.client.RestClient;
@@ -171,15 +172,23 @@ public class RestClientDocumentation {
             //tag::rest-client-body-shorter
             request.setJsonEntity("{\"json\":\"text\"}");
             //end::rest-client-body-shorter
+            {
                 //tag::rest-client-headers
-            request.addHeader("Accept", "text/plain");
+                RequestOptions.Builder options = request.getOptions().toBuilder();
-            request.addHeader("Cache-Control", "no-cache");
+                options.addHeader("Accept", "text/plain");
+                options.addHeader("Cache-Control", "no-cache");
+                request.setOptions(options);
                 //end::rest-client-headers
+            }
+            {
                 //tag::rest-client-response-consumer
-            request.setHttpAsyncResponseConsumerFactory(
+                RequestOptions.Builder options = request.getOptions().toBuilder();
+                options.setHttpAsyncResponseConsumerFactory(
                         new HttpAsyncResponseConsumerFactory.HeapBufferedResponseConsumerFactory(30 * 1024 * 1024));
+                request.setOptions(options);
                 //end::rest-client-response-consumer
             }
+        }
         {
             HttpEntity[] documents = new HttpEntity[10];
             //tag::rest-client-async-example

client/sniffer/src/main/java/org/elasticsearch/client/sniff/SniffOnFailureListener.java

@@ -58,7 +58,6 @@ public class SniffOnFailureListener extends RestClient.FailureListener {
         if (sniffer == null) {
             throw new IllegalStateException("sniffer was not set, unable to sniff on failure");
         }
-        //re-sniff immediately but take out the node that failed
+        sniffer.sniffOnFailure();
-        sniffer.sniffOnFailure(host);
     }
 }

client/sniffer/src/main/java/org/elasticsearch/client/sniff/Sniffer.java

@@ -31,12 +31,14 @@ import java.security.AccessController;
 import java.security.PrivilegedAction;
 import java.util.List;
 import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
 import java.util.concurrent.ScheduledExecutorService;
-import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
 import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicReference;
 
 /**
  * Class responsible for sniffing nodes from some source (default is elasticsearch itself) and setting them to a provided instance of
@@ -51,101 +53,175 @@ public class Sniffer implements Closeable {
     private static final Log logger = LogFactory.getLog(Sniffer.class);
     private static final String SNIFFER_THREAD_NAME = "es_rest_client_sniffer";
 
-    private final Task task;
+    private final HostsSniffer hostsSniffer;
+    private final RestClient restClient;
+    private final long sniffIntervalMillis;
+    private final long sniffAfterFailureDelayMillis;
+    private final Scheduler scheduler;
+    private final AtomicBoolean initialized = new AtomicBoolean(false);
+    private volatile ScheduledTask nextScheduledTask;
 
     Sniffer(RestClient restClient, HostsSniffer hostsSniffer, long sniffInterval, long sniffAfterFailureDelay) {
-        this.task = new Task(hostsSniffer, restClient, sniffInterval, sniffAfterFailureDelay);
+        this(restClient, hostsSniffer, new DefaultScheduler(), sniffInterval, sniffAfterFailureDelay);
+    }
+
+    Sniffer(RestClient restClient, HostsSniffer hostsSniffer, Scheduler scheduler,  long sniffInterval, long sniffAfterFailureDelay) {
+        this.hostsSniffer = hostsSniffer;
+        this.restClient = restClient;
+        this.sniffIntervalMillis = sniffInterval;
+        this.sniffAfterFailureDelayMillis = sniffAfterFailureDelay;
+        this.scheduler = scheduler;
+        /*
+         * The first sniffing round is async, so this constructor returns before nextScheduledTask is assigned to a task.
+         * The initialized flag is a protection against NPE due to that.
+         */
+        Task task = new Task(sniffIntervalMillis) {
+            @Override
+            public void run() {
+                super.run();
+                initialized.compareAndSet(false, true);
+            }
+        };
+        /*
+         * We do not keep track of the returned future as we never intend to cancel the initial sniffing round, we rather
+         * prevent any other operation from being executed till the sniffer is properly initialized
+         */
+        scheduler.schedule(task, 0L);
     }
 
     /**
-     * Triggers a new sniffing round and explicitly takes out the failed host provided as argument
+     * Schedule sniffing to run as soon as possible if it isn't already running. Once such sniffing round runs
+     * it will also schedule a new round after sniffAfterFailureDelay ms.
      */
-    public void sniffOnFailure(HttpHost failedHost) {
+    public void sniffOnFailure() {
-        this.task.sniffOnFailure(failedHost);
+        //sniffOnFailure does nothing until the initial sniffing round has been completed
+        if (initialized.get()) {
+            /*
+             * If sniffing is already running, there is no point in scheduling another round right after the current one.
+             * Concurrent calls may be checking the same task state, but only the first skip call on the same task returns true.
+             * The task may also get replaced while we check its state, in which case calling skip on it returns false.
+             */
+            if (this.nextScheduledTask.skip()) {
+                /*
+                 * We do not keep track of this future as the task will immediately run and we don't intend to cancel it
+                 * due to concurrent sniffOnFailure runs. Effectively the previous (now cancelled or skipped) task will stay
+                 * assigned to nextTask till this onFailure round gets run and schedules its corresponding afterFailure round.
+                 */
+                scheduler.schedule(new Task(sniffAfterFailureDelayMillis), 0L);
+            }
+        }
     }
 
-    @Override
+    enum TaskState {
-    public void close() throws IOException {
+        WAITING, SKIPPED, STARTED
-        task.shutdown();
     }
 
-    private static class Task implements Runnable {
+    class Task implements Runnable {
-        private final HostsSniffer hostsSniffer;
+        final long nextTaskDelay;
-        private final RestClient restClient;
+        final AtomicReference<TaskState> taskState = new AtomicReference<>(TaskState.WAITING);
 
-        private final long sniffIntervalMillis;
+        Task(long nextTaskDelay) {
-        private final long sniffAfterFailureDelayMillis;
+            this.nextTaskDelay = nextTaskDelay;
-        private final ScheduledExecutorService scheduledExecutorService;
-        private final AtomicBoolean running = new AtomicBoolean(false);
-        private ScheduledFuture<?> scheduledFuture;
-
-        private Task(HostsSniffer hostsSniffer, RestClient restClient, long sniffIntervalMillis, long sniffAfterFailureDelayMillis) {
-            this.hostsSniffer = hostsSniffer;
-            this.restClient = restClient;
-            this.sniffIntervalMillis = sniffIntervalMillis;
-            this.sniffAfterFailureDelayMillis = sniffAfterFailureDelayMillis;
-            SnifferThreadFactory threadFactory = new SnifferThreadFactory(SNIFFER_THREAD_NAME);
-            this.scheduledExecutorService = Executors.newScheduledThreadPool(1, threadFactory);
-            scheduleNextRun(0);
-        }
-
-        synchronized void scheduleNextRun(long delayMillis) {
-            if (scheduledExecutorService.isShutdown() == false) {
-                try {
-                    if (scheduledFuture != null) {
-                        //regardless of when the next sniff is scheduled, cancel it and schedule a new one with updated delay
-                        this.scheduledFuture.cancel(false);
-                    }
-                    logger.debug("scheduling next sniff in " + delayMillis + " ms");
-                    this.scheduledFuture = this.scheduledExecutorService.schedule(this, delayMillis, TimeUnit.MILLISECONDS);
-                } catch(Exception e) {
-                    logger.error("error while scheduling next sniffer task", e);
-                }
-            }
         }
 
         @Override
         public void run() {
-            sniff(null, sniffIntervalMillis);
+            /*
+             * Skipped or already started tasks do nothing. In most cases tasks will be cancelled and not run, but we want to protect for
+             * cases where future#cancel returns true yet the task runs. We want to make sure that such tasks do nothing otherwise they will
+             * schedule another round at the end and so on, leaving us with multiple parallel sniffing "tracks" whish is undesirable.
+             */
+            if (taskState.compareAndSet(TaskState.WAITING, TaskState.STARTED) == false) {
+                return;
             }
-
-        void sniffOnFailure(HttpHost failedHost) {
-            sniff(failedHost, sniffAfterFailureDelayMillis);
-        }
-
-        void sniff(HttpHost excludeHost, long nextSniffDelayMillis) {
-            if (running.compareAndSet(false, true)) {
             try {
+                sniff();
+            } catch (Exception e) {
+                logger.error("error while sniffing nodes", e);
+            } finally {
+                Task task = new Task(sniffIntervalMillis);
+                Future<?> future = scheduler.schedule(task, nextTaskDelay);
+                //tasks are run by a single threaded executor, so swapping is safe with a simple volatile variable
+                ScheduledTask previousTask = nextScheduledTask;
+                nextScheduledTask = new ScheduledTask(task, future);
+                assert initialized.get() == false ||
+                        previousTask.task.isSkipped() || previousTask.task.hasStarted() : "task that we are replacing is neither " +
+                        "cancelled nor has it ever started";
+            }
+        }
+
+        /**
+         * Returns true if the task has started, false in case it didn't start (yet?) or it was skipped
+         */
+        boolean hasStarted() {
+            return taskState.get() == TaskState.STARTED;
+        }
+
+        /**
+         * Sets this task to be skipped. Returns true if the task will be skipped, false if the task has already started.
+         */
+        boolean skip() {
+            /*
+             * Threads may still get run although future#cancel returns true. We make sure that a task is either cancelled (or skipped),
+             * or entirely run. In the odd case that future#cancel returns true and the thread still runs, the task won't do anything.
+             * In case future#cancel returns true but the task has already started, this state change will not succeed hence this method
+             * returns false and the task will normally run.
+             */
+            return taskState.compareAndSet(TaskState.WAITING, TaskState.SKIPPED);
+        }
+
+        /**
+         * Returns true if the task was set to be skipped before it was started
+         */
+        boolean isSkipped() {
+            return taskState.get() == TaskState.SKIPPED;
+        }
+    }
+
+    static final class ScheduledTask {
+        final Task task;
+        final Future<?> future;
+
+        ScheduledTask(Task task, Future<?> future) {
+            this.task = task;
+            this.future = future;
+        }
+
+        /**
+         * Cancels this task. Returns true if the task has been successfully cancelled, meaning it won't be executed
+         * or if it is its execution won't have any effect. Returns false if the task cannot be cancelled (possibly it was
+         * already cancelled or already completed).
+         */
+        boolean skip() {
+            /*
+             * Future#cancel should return false whenever a task cannot be cancelled, most likely as it has already started. We don't
+             * trust it much though so we try to cancel hoping that it will work.  At the same time we always call skip too, which means
+             * that if the task has already started the state change will fail. We could potentially not call skip when cancel returns
+             * false but we prefer to stay on the safe side.
+             */
+            future.cancel(false);
+            return task.skip();
+        }
+    }
+
+    final void sniff() throws IOException {
         List<HttpHost> sniffedHosts = hostsSniffer.sniffHosts();
+        if (logger.isDebugEnabled()) {
             logger.debug("sniffed hosts: " + sniffedHosts);
-                    if (excludeHost != null) {
-                        sniffedHosts.remove(excludeHost);
         }
         if (sniffedHosts.isEmpty()) {
             logger.warn("no hosts to set, hosts will be updated at the next sniffing round");
         } else {
-                        this.restClient.setHosts(sniffedHosts.toArray(new HttpHost[sniffedHosts.size()]));
+            restClient.setHosts(sniffedHosts.toArray(new HttpHost[sniffedHosts.size()]));
-                    }
-                } catch (Exception e) {
-                    logger.error("error while sniffing nodes", e);
-                } finally {
-                    scheduleNextRun(nextSniffDelayMillis);
-                    running.set(false);
-                }
         }
     }
 
-        synchronized void shutdown() {
+    @Override
-            scheduledExecutorService.shutdown();
+    public void close() {
-            try {
+        if (initialized.get()) {
-                if (scheduledExecutorService.awaitTermination(1000, TimeUnit.MILLISECONDS)) {
+            nextScheduledTask.skip();
-                    return;
-                }
-                scheduledExecutorService.shutdownNow();
-            } catch (InterruptedException e) {
-                Thread.currentThread().interrupt();
-            }
         }
+        this.scheduler.shutdown();
     }
 
     /**
@@ -158,8 +234,62 @@ public class Sniffer implements Closeable {
         return new SnifferBuilder(restClient);
     }
 
-    private static class SnifferThreadFactory implements ThreadFactory {
+    /**
+     * The Scheduler interface allows to isolate the sniffing scheduling aspects so that we can test
+     * the sniffer by injecting when needed a custom scheduler that is more suited for testing.
+     */
+    interface Scheduler {
+        /**
+         * Schedules the provided {@link Runnable} to be executed in <code>delayMillis</code> milliseconds
+         */
+        Future<?> schedule(Task task, long delayMillis);
 
+        /**
+         * Shuts this scheduler down
+         */
+        void shutdown();
+    }
+
+    /**
+     * Default implementation of {@link Scheduler}, based on {@link ScheduledExecutorService}
+     */
+    static final class DefaultScheduler implements Scheduler {
+        final ScheduledExecutorService executor;
+
+        DefaultScheduler() {
+            this(initScheduledExecutorService());
+        }
+
+        DefaultScheduler(ScheduledExecutorService executor) {
+            this.executor = executor;
+        }
+
+        private static ScheduledExecutorService initScheduledExecutorService() {
+            ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(1, new SnifferThreadFactory(SNIFFER_THREAD_NAME));
+            executor.setRemoveOnCancelPolicy(true);
+            return executor;
+        }
+
+        @Override
+        public Future<?> schedule(Task task, long delayMillis) {
+            return executor.schedule(task, delayMillis, TimeUnit.MILLISECONDS);
+        }
+
+        @Override
+        public void shutdown() {
+            executor.shutdown();
+            try {
+                if (executor.awaitTermination(1000, TimeUnit.MILLISECONDS)) {
+                    return;
+                }
+                executor.shutdownNow();
+            } catch (InterruptedException ignore) {
+                Thread.currentThread().interrupt();
+            }
+        }
+    }
+
+    static class SnifferThreadFactory implements ThreadFactory {
         private final AtomicInteger threadNumber = new AtomicInteger(1);
         private final String namePrefix;
         private final ThreadFactory originalThreadFactory;

client/sniffer/src/test/java/org/elasticsearch/client/sniff/MockHostsSniffer.java

@@ -21,7 +21,6 @@ package org.elasticsearch.client.sniff;
 
 import org.apache.http.HttpHost;
 
-import java.io.IOException;
 import java.util.Collections;
 import java.util.List;
 
@@ -30,7 +29,7 @@ import java.util.List;
  */
 class MockHostsSniffer implements HostsSniffer {
     @Override
-    public List<HttpHost> sniffHosts() throws IOException {
+    public List<HttpHost> sniffHosts() {
         return Collections.singletonList(new HttpHost("localhost", 9200));
     }
 }

client/sniffer/src/test/java/org/elasticsearch/client/sniff/SnifferTests.java

@@ -0,0 +1,656 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.client.sniff;
+
+import org.apache.http.HttpHost;
+import org.elasticsearch.client.RestClient;
+import org.elasticsearch.client.RestClientTestCase;
+import org.elasticsearch.client.sniff.Sniffer.DefaultScheduler;
+import org.elasticsearch.client.sniff.Sniffer.Scheduler;
+import org.mockito.Matchers;
+import org.mockito.invocation.InvocationOnMock;
+import org.mockito.stubbing.Answer;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.CancellationException;
+import java.util.concurrent.CopyOnWriteArraySet;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicReference;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.CoreMatchers.instanceOf;
+import static org.hamcrest.Matchers.greaterThan;
+import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertSame;
+import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+import static org.mockito.Matchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.Mockito.when;
+
+public class SnifferTests extends RestClientTestCase {
+
+    /**
+     * Tests the {@link Sniffer#sniff()} method in isolation. Verifies that it uses the {@link HostsSniffer} implementation
+     * to retrieve nodes and set them (when not empty) to the provided {@link RestClient} instance.
+     */
+    public void testSniff() throws IOException {
+        HttpHost initialHost = new HttpHost("localhost", 9200);
+        try (RestClient restClient = RestClient.builder(initialHost).build()) {
+            Scheduler noOpScheduler = new Scheduler() {
+                @Override
+                public Future<?> schedule(Sniffer.Task task, long delayMillis) {
+                    return mock(Future.class);
+                }
+
+                @Override
+                public void shutdown() {
+
+                }
+            };
+            CountingHostsSniffer hostsSniffer = new CountingHostsSniffer();
+            int iters = randomIntBetween(5, 30);
+            try (Sniffer sniffer = new Sniffer(restClient, hostsSniffer, noOpScheduler, 1000L, -1)){
+                {
+                    assertEquals(1, restClient.getHosts().size());
+                    HttpHost httpHost = restClient.getHosts().get(0);
+                    assertEquals("localhost", httpHost.getHostName());
+                    assertEquals(9200, httpHost.getPort());
+                }
+                int emptyList = 0;
+                int failures = 0;
+                int runs = 0;
+                List<HttpHost> lastHosts = Collections.singletonList(initialHost);
+                for (int i = 0; i < iters; i++) {
+                    try {
+                        runs++;
+                        sniffer.sniff();
+                        if (hostsSniffer.failures.get() > failures) {
+                            failures++;
+                            fail("should have failed given that hostsSniffer says it threw an exception");
+                        } else if (hostsSniffer.emptyList.get() > emptyList) {
+                            emptyList++;
+                            assertEquals(lastHosts, restClient.getHosts());
+                        } else {
+                            assertNotEquals(lastHosts, restClient.getHosts());
+                            List<HttpHost> expectedHosts = CountingHostsSniffer.buildHosts(runs);
+                            assertEquals(expectedHosts, restClient.getHosts());
+                            lastHosts = restClient.getHosts();
+                        }
+                    } catch(IOException e) {
+                        if (hostsSniffer.failures.get() > failures) {
+                            failures++;
+                            assertEquals("communication breakdown", e.getMessage());
+                        }
+                    }
+                }
+                assertEquals(hostsSniffer.emptyList.get(), emptyList);
+                assertEquals(hostsSniffer.failures.get(), failures);
+                assertEquals(hostsSniffer.runs.get(), runs);
+            }
+        }
+    }
+
+    /**
+     * Test multiple sniffing rounds by mocking the {@link Scheduler} as well as the {@link HostsSniffer}.
+     * Simulates the ordinary behaviour of {@link Sniffer} when sniffing on failure is not enabled.
+     * The {@link CountingHostsSniffer} doesn't make any network connection but may throw exception or return no hosts, which makes
+     * it possible to verify that errors are properly handled and don't affect subsequent runs and their scheduling.
+     * The {@link Scheduler} implementation submits rather than scheduling tasks, meaning that it doesn't respect the requested sniff
+     * delays while allowing to assert that the requested delays for each requested run and the following one are the expected values.
+     */
+    public void testOrdinarySniffRounds() throws Exception {
+        final long sniffInterval = randomLongBetween(1, Long.MAX_VALUE);
+        long sniffAfterFailureDelay = randomLongBetween(1, Long.MAX_VALUE);
+        RestClient restClient = mock(RestClient.class);
+        CountingHostsSniffer hostsSniffer = new CountingHostsSniffer();
+        final int iters = randomIntBetween(30, 100);
+        final Set<Future<?>> futures = new CopyOnWriteArraySet<>();
+        final CountDownLatch completionLatch = new CountDownLatch(1);
+        final AtomicInteger runs = new AtomicInteger(iters);
+        final ExecutorService executor = Executors.newSingleThreadExecutor();
+        final AtomicReference<Future<?>> lastFuture = new AtomicReference<>();
+        final AtomicReference<Sniffer.Task> lastTask = new AtomicReference<>();
+        Scheduler scheduler = new Scheduler() {
+            @Override
+            public Future<?> schedule(Sniffer.Task task, long delayMillis) {
+                assertEquals(sniffInterval, task.nextTaskDelay);
+                int numberOfRuns = runs.getAndDecrement();
+                if (numberOfRuns == iters) {
+                    //the first call is to schedule the first sniff round from the Sniffer constructor, with delay O
+                    assertEquals(0L, delayMillis);
+                    assertEquals(sniffInterval, task.nextTaskDelay);
+                } else {
+                    //all of the subsequent times "schedule" is called with delay set to the configured sniff interval
+                    assertEquals(sniffInterval, delayMillis);
+                    assertEquals(sniffInterval, task.nextTaskDelay);
+                    if (numberOfRuns == 0) {
+                        completionLatch.countDown();
+                        return null;
+                    }
+                }
+                //we submit rather than scheduling to make the test quick and not depend on time
+                Future<?> future = executor.submit(task);
+                futures.add(future);
+                if (numberOfRuns == 1) {
+                    lastFuture.set(future);
+                    lastTask.set(task);
+                }
+                return future;
+            }
+
+            @Override
+            public void shutdown() {
+                //the executor is closed externally, shutdown is tested separately
+            }
+        };
+        try {
+            new Sniffer(restClient, hostsSniffer, scheduler, sniffInterval, sniffAfterFailureDelay);
+            assertTrue("timeout waiting for sniffing rounds to be completed", completionLatch.await(1000, TimeUnit.MILLISECONDS));
+            assertEquals(iters, futures.size());
+            //the last future is the only one that may not be completed yet, as the count down happens
+            //while scheduling the next round which is still part of the execution of the runnable itself.
+            assertTrue(lastTask.get().hasStarted());
+            lastFuture.get().get();
+            for (Future<?> future : futures) {
+                assertTrue(future.isDone());
+                future.get();
+            }
+        } finally {
+            executor.shutdown();
+            assertTrue(executor.awaitTermination(1000, TimeUnit.MILLISECONDS));
+        }
+        int totalRuns = hostsSniffer.runs.get();
+        assertEquals(iters, totalRuns);
+        int setHostsRuns = totalRuns - hostsSniffer.failures.get() - hostsSniffer.emptyList.get();
+        verify(restClient, times(setHostsRuns)).setHosts(Matchers.<HttpHost>anyVararg());
+        verifyNoMoreInteractions(restClient);
+    }
+
+    /**
+     * Test that {@link Sniffer#close()} shuts down the underlying {@link Scheduler}, and that such calls are idempotent.
+     * Also verifies that the next scheduled round gets cancelled.
+     */
+    public void testClose() {
+        final Future<?> future = mock(Future.class);
+        long sniffInterval = randomLongBetween(1, Long.MAX_VALUE);
+        long sniffAfterFailureDelay = randomLongBetween(1, Long.MAX_VALUE);
+        RestClient restClient = mock(RestClient.class);
+        final AtomicInteger shutdown = new AtomicInteger(0);
+        final AtomicBoolean initialized = new AtomicBoolean(false);
+        Scheduler scheduler = new Scheduler() {
+            @Override
+            public Future<?> schedule(Sniffer.Task task, long delayMillis) {
+                if (initialized.compareAndSet(false, true)) {
+                    //run from the same thread so the sniffer gets for sure initialized and the scheduled task gets cancelled on close
+                    task.run();
+                }
+                return future;
+            }
+
+            @Override
+            public void shutdown() {
+                shutdown.incrementAndGet();
+            }
+        };
+
+        Sniffer sniffer = new Sniffer(restClient, new MockHostsSniffer(), scheduler, sniffInterval, sniffAfterFailureDelay);
+        assertEquals(0, shutdown.get());
+        int iters = randomIntBetween(3, 10);
+        for (int i = 1; i <= iters; i++) {
+            sniffer.close();
+            verify(future, times(i)).cancel(false);
+            assertEquals(i, shutdown.get());
+        }
+    }
+
+    public void testSniffOnFailureNotInitialized() {
+        RestClient restClient = mock(RestClient.class);
+        CountingHostsSniffer hostsSniffer = new CountingHostsSniffer();
+        long sniffInterval = randomLongBetween(1, Long.MAX_VALUE);
+        long sniffAfterFailureDelay = randomLongBetween(1, Long.MAX_VALUE);
+        final AtomicInteger scheduleCalls = new AtomicInteger(0);
+        Scheduler scheduler = new Scheduler() {
+            @Override
+            public Future<?> schedule(Sniffer.Task task, long delayMillis) {
+                scheduleCalls.incrementAndGet();
+                return null;
+            }
+
+            @Override
+            public void shutdown() {
+            }
+        };
+
+        Sniffer sniffer = new Sniffer(restClient, hostsSniffer, scheduler, sniffInterval, sniffAfterFailureDelay);
+        for (int i = 0; i < 10; i++) {
+            sniffer.sniffOnFailure();
+        }
+        assertEquals(1, scheduleCalls.get());
+        int totalRuns = hostsSniffer.runs.get();
+        assertEquals(0, totalRuns);
+        int setHostsRuns = totalRuns - hostsSniffer.failures.get() - hostsSniffer.emptyList.get();
+        verify(restClient, times(setHostsRuns)).setHosts(Matchers.<HttpHost>anyVararg());
+        verifyNoMoreInteractions(restClient);
+    }
+
+    /**
+     * Test behaviour when a bunch of onFailure sniffing rounds are triggered in parallel. Each run will always
+     * schedule a subsequent afterFailure round. Also, for each onFailure round that starts, the net scheduled round
+     * (either afterFailure or ordinary) gets cancelled.
+     */
+    public void testSniffOnFailure() throws Exception {
+        RestClient restClient = mock(RestClient.class);
+        CountingHostsSniffer hostsSniffer = new CountingHostsSniffer();
+        final AtomicBoolean initializing = new AtomicBoolean(true);
+        final long sniffInterval = randomLongBetween(1, Long.MAX_VALUE);
+        final long sniffAfterFailureDelay = randomLongBetween(1, Long.MAX_VALUE);
+        int minNumOnFailureRounds = randomIntBetween(5, 10);
+        final CountDownLatch initializingLatch = new CountDownLatch(1);
+        final Set<Sniffer.ScheduledTask> ordinaryRoundsTasks = new CopyOnWriteArraySet<>();
+        final AtomicReference<Future<?>> initializingFuture = new AtomicReference<>();
+        final Set<Sniffer.ScheduledTask> onFailureTasks = new CopyOnWriteArraySet<>();
+        final Set<Sniffer.ScheduledTask> afterFailureTasks = new CopyOnWriteArraySet<>();
+        final AtomicBoolean onFailureCompleted = new AtomicBoolean(false);
+        final CountDownLatch completionLatch = new CountDownLatch(1);
+        final ScheduledExecutorService executor = Executors.newSingleThreadScheduledExecutor();
+        try {
+            Scheduler scheduler = new Scheduler() {
+                @Override
+                public Future<?> schedule(final Sniffer.Task task, long delayMillis) {
+                    if (initializing.compareAndSet(true, false)) {
+                        assertEquals(0L, delayMillis);
+                        Future<?> future = executor.submit(new Runnable() {
+                            @Override
+                            public void run() {
+                                try {
+                                    task.run();
+                                } finally {
+                                    //we need to make sure that the sniffer is initialized, so the sniffOnFailure
+                                    //call does what it needs to do. Otherwise nothing happens until initialized.
+                                    initializingLatch.countDown();
+                                }
+                            }
+                        });
+                        assertTrue(initializingFuture.compareAndSet(null, future));
+                        return future;
+                    }
+                    if (delayMillis == 0L) {
+                        Future<?> future = executor.submit(task);
+                        onFailureTasks.add(new Sniffer.ScheduledTask(task, future));
+                        return future;
+                    }
+                    if (delayMillis == sniffAfterFailureDelay) {
+                        Future<?> future = scheduleOrSubmit(task);
+                        afterFailureTasks.add(new Sniffer.ScheduledTask(task, future));
+                        return future;
+                    }
+
+                    assertEquals(sniffInterval, delayMillis);
+                    assertEquals(sniffInterval, task.nextTaskDelay);
+
+                    if (onFailureCompleted.get() && onFailureTasks.size() == afterFailureTasks.size()) {
+                        completionLatch.countDown();
+                        return mock(Future.class);
+                    }
+
+                    Future<?> future = scheduleOrSubmit(task);
+                    ordinaryRoundsTasks.add(new Sniffer.ScheduledTask(task, future));
+                    return future;
+                }
+
+                private Future<?> scheduleOrSubmit(Sniffer.Task task) {
+                    if (randomBoolean()) {
+                        return executor.schedule(task, randomLongBetween(0L, 200L), TimeUnit.MILLISECONDS);
+                    } else {
+                        return executor.submit(task);
+                    }
+                }
+
+                @Override
+                public void shutdown() {
+                }
+            };
+            final Sniffer sniffer = new Sniffer(restClient, hostsSniffer, scheduler, sniffInterval, sniffAfterFailureDelay);
+            assertTrue("timeout waiting for sniffer to get initialized", initializingLatch.await(1000, TimeUnit.MILLISECONDS));
+
+            ExecutorService onFailureExecutor = Executors.newFixedThreadPool(randomIntBetween(5, 20));
+            Set<Future<?>> onFailureFutures = new CopyOnWriteArraySet<>();
+            try {
+                //with tasks executing quickly one after each other, it is very likely that the onFailure round gets skipped
+                //as another round is already running. We retry till enough runs get through as that's what we want to test.
+                while (onFailureTasks.size() < minNumOnFailureRounds) {
+                    onFailureFutures.add(onFailureExecutor.submit(new Runnable() {
+                        @Override
+                        public void run() {
+                            sniffer.sniffOnFailure();
+                        }
+                    }));
+                }
+                assertThat(onFailureFutures.size(), greaterThanOrEqualTo(minNumOnFailureRounds));
+                for (Future<?> onFailureFuture : onFailureFutures) {
+                    assertNull(onFailureFuture.get());
+                }
+                onFailureCompleted.set(true);
+            } finally {
+                onFailureExecutor.shutdown();
+                onFailureExecutor.awaitTermination(1000, TimeUnit.MILLISECONDS);
+            }
+
+            assertFalse(initializingFuture.get().isCancelled());
+            assertTrue(initializingFuture.get().isDone());
+            assertNull(initializingFuture.get().get());
+
+            assertTrue("timeout waiting for sniffing rounds to be completed", completionLatch.await(1000, TimeUnit.MILLISECONDS));
+            assertThat(onFailureTasks.size(), greaterThanOrEqualTo(minNumOnFailureRounds));
+            assertEquals(onFailureTasks.size(), afterFailureTasks.size());
+
+            for (Sniffer.ScheduledTask onFailureTask : onFailureTasks) {
+                assertFalse(onFailureTask.future.isCancelled());
+                assertTrue(onFailureTask.future.isDone());
+                assertNull(onFailureTask.future.get());
+                assertTrue(onFailureTask.task.hasStarted());
+                assertFalse(onFailureTask.task.isSkipped());
+            }
+
+            int cancelledTasks = 0;
+            int completedTasks = onFailureTasks.size() + 1;
+            for (Sniffer.ScheduledTask afterFailureTask : afterFailureTasks) {
+                if (assertTaskCancelledOrCompleted(afterFailureTask)) {
+                    completedTasks++;
+                } else {
+                    cancelledTasks++;
+                }
+            }
+
+            assertThat(ordinaryRoundsTasks.size(), greaterThan(0));
+            for (Sniffer.ScheduledTask task : ordinaryRoundsTasks) {
+                if (assertTaskCancelledOrCompleted(task)) {
+                    completedTasks++;
+                } else {
+                    cancelledTasks++;
+                }
+            }
+            assertEquals(onFailureTasks.size(), cancelledTasks);
+
+            assertEquals(completedTasks, hostsSniffer.runs.get());
+            int setHostsRuns = hostsSniffer.runs.get() - hostsSniffer.failures.get() - hostsSniffer.emptyList.get();
+            verify(restClient, times(setHostsRuns)).setHosts(Matchers.<HttpHost>anyVararg());
+            verifyNoMoreInteractions(restClient);
+        } finally {
+            executor.shutdown();
+            executor.awaitTermination(1000L, TimeUnit.MILLISECONDS);
+        }
+    }
+
+    private static boolean assertTaskCancelledOrCompleted(Sniffer.ScheduledTask task) throws ExecutionException, InterruptedException {
+        if (task.task.isSkipped()) {
+            assertTrue(task.future.isCancelled());
+            try {
+                task.future.get();
+                fail("cancellation exception should have been thrown");
+            } catch(CancellationException ignore) {
+            }
+            return false;
+        } else {
+            try {
+                assertNull(task.future.get());
+            } catch(CancellationException ignore) {
+                assertTrue(task.future.isCancelled());
+            }
+            assertTrue(task.future.isDone());
+            assertTrue(task.task.hasStarted());
+            return true;
+        }
+    }
+
+    public void testTaskCancelling() throws Exception {
+        RestClient restClient = mock(RestClient.class);
+        HostsSniffer hostsSniffer = mock(HostsSniffer.class);
+        Scheduler noOpScheduler = new Scheduler() {
+            @Override
+            public Future<?> schedule(Sniffer.Task task, long delayMillis) {
+                return null;
+            }
+
+            @Override
+            public void shutdown() {
+            }
+        };
+        Sniffer sniffer = new Sniffer(restClient, hostsSniffer, noOpScheduler, 0L, 0L);
+        ScheduledExecutorService executor = Executors.newSingleThreadScheduledExecutor();
+        try {
+            int numIters = randomIntBetween(50, 100);
+            for (int i = 0; i < numIters; i++) {
+                Sniffer.Task task = sniffer.new Task(0L);
+                TaskWrapper wrapper = new TaskWrapper(task);
+                Future<?> future;
+                if (rarely()) {
+                    future = executor.schedule(wrapper, randomLongBetween(0L, 200L), TimeUnit.MILLISECONDS);
+                } else {
+                    future = executor.submit(wrapper);
+                }
+                Sniffer.ScheduledTask scheduledTask = new Sniffer.ScheduledTask(task, future);
+                boolean skip = scheduledTask.skip();
+                try {
+                    assertNull(future.get());
+                } catch(CancellationException ignore) {
+                    assertTrue(future.isCancelled());
+                }
+
+                if (skip) {
+                    //the task was either cancelled before starting, in which case it will never start (thanks to Future#cancel),
+                    //or skipped, in which case it will run but do nothing (thanks to Task#skip).
+                    //Here we want to make sure that whenever skip returns true, the task either won't run or it won't do anything,
+                    //otherwise we may end up with parallel sniffing tracks given that each task schedules the following one. We need to
+                    // make sure that onFailure takes scheduling over while at the same time ordinary rounds don't go on.
+                    assertFalse(task.hasStarted());
+                    assertTrue(task.isSkipped());
+                    assertTrue(future.isCancelled());
+                    assertTrue(future.isDone());
+                } else {
+                    //if a future is cancelled when its execution has already started, future#get throws CancellationException before
+                    //completion. The execution continues though so we use a latch to try and wait for the task to be completed.
+                    //Here we want to make sure that whenever skip returns false, the task will be completed, otherwise we may be
+                    //missing to schedule the following round, which means no sniffing will ever happen again besides on failure sniffing.
+                    assertTrue(wrapper.await());
+                    //the future may or may not be cancelled but the task has for sure started and completed
+                    assertTrue(task.toString(), task.hasStarted());
+                    assertFalse(task.isSkipped());
+                    assertTrue(future.isDone());
+                }
+                //subsequent cancel calls return false for sure
+                int cancelCalls = randomIntBetween(1, 10);
+                for (int j = 0; j < cancelCalls; j++) {
+                    assertFalse(scheduledTask.skip());
+                }
+            }
+        } finally {
+            executor.shutdown();
+            executor.awaitTermination(1000, TimeUnit.MILLISECONDS);
+        }
+    }
+
+    /**
+     * Wraps a {@link Sniffer.Task} and allows to wait for its completion. This is needed to verify
+     * that tasks are either never started or always completed. Calling {@link Future#get()} against a cancelled future will
+     * throw {@link CancellationException} straight-away but the execution of the task will continue if it had already started,
+     * in which case {@link Future#cancel(boolean)} returns true which is not very helpful.
+     */
+    private static final class TaskWrapper implements Runnable {
+        final Sniffer.Task task;
+        final CountDownLatch completionLatch = new CountDownLatch(1);
+
+        TaskWrapper(Sniffer.Task task) {
+            this.task = task;
+        }
+
+        @Override
+        public void run() {
+            try {
+                task.run();
+            } finally {
+                completionLatch.countDown();
+            }
+        }
+
+        boolean await() throws InterruptedException {
+            return completionLatch.await(1000, TimeUnit.MILLISECONDS);
+        }
+    }
+
+    /**
+     * Mock {@link HostsSniffer} implementation used for testing, which most of the times return a fixed host.
+     * It rarely throws exception or return an empty list of hosts, to make sure that such situations are properly handled.
+     * It also asserts that it never gets called concurrently, based on the assumption that only one sniff run can be run
+     * at a given point in time.
+     */
+    private static class CountingHostsSniffer implements HostsSniffer {
+        private final AtomicInteger runs = new AtomicInteger(0);
+        private final AtomicInteger failures = new AtomicInteger(0);
+        private final AtomicInteger emptyList = new AtomicInteger(0);
+
+        @Override
+        public List<HttpHost> sniffHosts() throws IOException {
+            int run = runs.incrementAndGet();
+            if (rarely()) {
+                failures.incrementAndGet();
+                //check that if communication breaks, sniffer keeps on working
+                throw new IOException("communication breakdown");
+            }
+            if (rarely()) {
+                emptyList.incrementAndGet();
+                return Collections.emptyList();
+            }
+            return buildHosts(run);
+        }
+
+        private static List<HttpHost> buildHosts(int run) {
+            int size = run % 5 + 1;
+            assert size > 0;
+            List<HttpHost> hosts = new ArrayList<>(size);
+            for (int i = 0; i < size; i++) {
+                hosts.add(new HttpHost("sniffed-" + run, 9200 + i));
+            }
+            return hosts;
+        }
+    }
+
+    @SuppressWarnings("unchecked")
+    public void testDefaultSchedulerSchedule() {
+        RestClient restClient = mock(RestClient.class);
+        HostsSniffer hostsSniffer = mock(HostsSniffer.class);
+        Scheduler noOpScheduler = new Scheduler() {
+            @Override
+            public Future<?> schedule(Sniffer.Task task, long delayMillis) {
+                return mock(Future.class);
+            }
+
+            @Override
+            public void shutdown() {
+
+            }
+        };
+        Sniffer sniffer = new Sniffer(restClient, hostsSniffer, noOpScheduler, 0L, 0L);
+        Sniffer.Task task = sniffer.new Task(randomLongBetween(1, Long.MAX_VALUE));
+
+        ScheduledExecutorService scheduledExecutorService = mock(ScheduledExecutorService.class);
+        final ScheduledFuture<?> mockedFuture = mock(ScheduledFuture.class);
+        when(scheduledExecutorService.schedule(any(Runnable.class), any(Long.class), any(TimeUnit.class)))
+                .then(new Answer<ScheduledFuture<?>>() {
+                    @Override
+                    public ScheduledFuture<?> answer(InvocationOnMock invocationOnMock) {
+                        return mockedFuture;
+                    }
+        });
+        DefaultScheduler scheduler = new DefaultScheduler(scheduledExecutorService);
+        long delay = randomLongBetween(1, Long.MAX_VALUE);
+        Future<?> future = scheduler.schedule(task, delay);
+        assertSame(mockedFuture, future);
+        verify(scheduledExecutorService).schedule(task, delay, TimeUnit.MILLISECONDS);
+        verifyNoMoreInteractions(scheduledExecutorService, mockedFuture);
+    }
+
+    public void testDefaultSchedulerThreadFactory() {
+        DefaultScheduler defaultScheduler = new DefaultScheduler();
+        try {
+            ScheduledExecutorService executorService = defaultScheduler.executor;
+            assertThat(executorService, instanceOf(ScheduledThreadPoolExecutor.class));
+            assertThat(executorService, instanceOf(ScheduledThreadPoolExecutor.class));
+            ScheduledThreadPoolExecutor executor = (ScheduledThreadPoolExecutor) executorService;
+            assertTrue(executor.getRemoveOnCancelPolicy());
+            assertFalse(executor.getContinueExistingPeriodicTasksAfterShutdownPolicy());
+            assertTrue(executor.getExecuteExistingDelayedTasksAfterShutdownPolicy());
+            assertThat(executor.getThreadFactory(), instanceOf(Sniffer.SnifferThreadFactory.class));
+            int iters = randomIntBetween(3, 10);
+            for (int i = 1; i <= iters; i++) {
+                Thread thread = executor.getThreadFactory().newThread(new Runnable() {
+                    @Override
+                    public void run() {
+
+                    }
+                });
+                assertThat(thread.getName(), equalTo("es_rest_client_sniffer[T#" + i + "]"));
+                assertThat(thread.isDaemon(), is(true));
+            }
+        } finally {
+            defaultScheduler.shutdown();
+        }
+    }
+
+    public void testDefaultSchedulerShutdown() throws Exception {
+        ScheduledThreadPoolExecutor executor = mock(ScheduledThreadPoolExecutor.class);
+        DefaultScheduler defaultScheduler = new DefaultScheduler(executor);
+        defaultScheduler.shutdown();
+        verify(executor).shutdown();
+        verify(executor).awaitTermination(1000, TimeUnit.MILLISECONDS);
+        verify(executor).shutdownNow();
+        verifyNoMoreInteractions(executor);
+
+        when(executor.awaitTermination(1000, TimeUnit.MILLISECONDS)).thenReturn(true);
+        defaultScheduler.shutdown();
+        verify(executor, times(2)).shutdown();
+        verify(executor, times(2)).awaitTermination(1000, TimeUnit.MILLISECONDS);
+        verifyNoMoreInteractions(executor);
+    }
+}

docs/README.asciidoc

@@ -6,7 +6,9 @@ See: https://github.com/elastic/docs
 Snippets marked with `// CONSOLE` are automatically annotated with "VIEW IN
 CONSOLE" and "COPY AS CURL" in the documentation and are automatically tested
 by the command `gradle :docs:check`. To test just the docs from a single page,
-use e.g. `gradle :docs:check -Dtests.method="*rollover*"`.
+use e.g. `gradle :docs:check -Dtests.method="\*rollover*"`.
+
+NOTE: If you have an elasticsearch-extra folder alongside your elasticsearch folder, you must temporarily rename it when you are testing 6.3 or later branches. 
 
 By default each `// CONSOLE` snippet runs as its own isolated test. You can
 manipulate the test execution in the following ways:

docs/java-rest/high-level/cluster/get_pipeline.asciidoc

@@ -0,0 +1,75 @@
+[[java-rest-high-cluster-get-pipeline]]
+=== Get Pipeline API
+
+[[java-rest-high-cluster-get-pipeline-request]]
+==== Get Pipeline Request
+
+A `GetPipelineRequest` requires one or more `pipelineIds` to fetch.
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests}/ClusterClientDocumentationIT.java[get-pipeline-request]
+--------------------------------------------------
+<1> The pipeline id to fetch
+
+==== Optional arguments
+The following arguments can optionally be provided:
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests}/ClusterClientDocumentationIT.java[get-pipeline-request-masterTimeout]
+--------------------------------------------------
+<1> Timeout to connect to the master node as a `TimeValue`
+<2> Timeout to connect to the master node as a `String`
+
+[[java-rest-high-cluster-get-pipeline-sync]]
+==== Synchronous Execution
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests}/ClusterClientDocumentationIT.java[get-pipeline-execute]
+--------------------------------------------------
+<1> Execute the request and get back the response in a GetPipelineResponse object.
+
+[[java-rest-high-cluster-get-pipeline-async]]
+==== Asynchronous Execution
+
+The asynchronous execution of a get pipeline request requires both the `GetPipelineRequest`
+instance and an `ActionListener` instance to be passed to the asynchronous
+method:
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests}/ClusterClientDocumentationIT.java[get-pipeline-execute-async]
+--------------------------------------------------
+<1> The `GetPipelineRequest` to execute and the `ActionListener` to use when
+the execution completes
+
+The asynchronous method does not block and returns immediately. Once it is
+completed the `ActionListener` is called back using the `onResponse` method
+if the execution successfully completed or using the `onFailure` method if
+it failed.
+
+A typical listener for `GetPipelineResponse` looks like:
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests}/ClusterClientDocumentationIT.java[get-pipeline-execute-listener]
+--------------------------------------------------
+<1> Called when the execution is successfully completed. The response is
+provided as an argument
+<2> Called in case of failure. The raised exception is provided as an argument
+
+[[java-rest-high-cluster-get-pipeline-response]]
+==== Get Pipeline Response
+
+The returned `GetPipelineResponse` allows to retrieve information about the executed
+ operation as follows:
+
+["source","java",subs="attributes,callouts,macros"]
+--------------------------------------------------
+include-tagged::{doc-tests}/ClusterClientDocumentationIT.java[get-pipeline-response]
+--------------------------------------------------
+<1> Check if a matching pipeline id was found or not.
+<2> Get the list of pipelines found as a list of `PipelineConfig` objects.
+<3> Get the individual configuration of each pipeline as a `Map<String, Object>`.

docs/java-rest/high-level/supported-apis.asciidoc

@@ -107,9 +107,11 @@ The Java High Level REST Client supports the following Cluster APIs:
 
 * <<java-rest-high-cluster-put-settings>>
 * <<java-rest-high-cluster-put-pipeline>>
+* <<java-rest-high-cluster-get-pipeline>>
 
 include::cluster/put_settings.asciidoc[]
 include::cluster/put_pipeline.asciidoc[]
+include::cluster/get_pipeline.asciidoc[]
 
 == Snapshot APIs
 

docs/reference/mapping/types/keyword.asciidoc

@@ -103,6 +103,12 @@ The following parameters are accepted by `keyword` fields:
     How to pre-process the keyword prior to indexing. Defaults to `null`,
     meaning the keyword is kept as-is.
 
+`split_queries_on_whitespace`::
+
+    Whether <<full-text-queries,full text queries>> should split the input on whitespace
+    when building a query for this field.
+    Accepts `true` or `false` (default).
+
 NOTE: Indexes imported from 2.x do not support `keyword`. Instead they will
 attempt to downgrade `keyword` into `string`. This allows you to merge modern
 mappings with legacy mappings. Long lived indexes will have to be recreated

docs/reference/search/suggesters/context-suggest.asciidoc

@@ -84,6 +84,10 @@ PUT place_path_category
 NOTE: Adding context mappings increases the index size for completion field. The completion index
 is entirely heap resident, you can monitor the completion field index size using <<indices-stats>>.
 
+NOTE: deprecated[7.0.0, Indexing a suggestion without context on a context enabled completion field is deprecated
+and will be removed in the next major release. If you want to index a suggestion that matches all contexts you should
+add a special context for it.]
+
 [[suggester-context-category]]
 [float]
 ==== Category Context
@@ -156,9 +160,9 @@ POST place/_search?pretty
 // CONSOLE
 // TEST[continued]
 
-NOTE: When no categories are provided at query-time, all indexed documents are considered.
+Note: deprecated[7.0.0, When no categories are provided at query-time, all indexed documents are considered.
-Querying with no categories on a category enabled completion field should be avoided, as it
+Querying with no categories on a category enabled completion field is deprecated and will be removed in the next major release
-will degrade search performance.
+as it degrades search performance considerably.]
 
 Suggestions with certain categories can be boosted higher than others.
 The following filters suggestions by categories and additionally boosts

modules/ingest-common/src/main/java/org/elasticsearch/ingest/common/GrokProcessorGetAction.java

@@ -52,8 +52,7 @@ import static org.elasticsearch.ingest.common.IngestCommonPlugin.GROK_PATTERNS;
 import static org.elasticsearch.rest.RestRequest.Method.GET;
 import static org.elasticsearch.rest.RestStatus.OK;
 
-public class GrokProcessorGetAction extends Action<GrokProcessorGetAction.Request,
+public class GrokProcessorGetAction extends Action<GrokProcessorGetAction.Request, GrokProcessorGetAction.Response> {
-    GrokProcessorGetAction.Response, GrokProcessorGetAction.RequestBuilder> {
 
     public static final GrokProcessorGetAction INSTANCE = new GrokProcessorGetAction();
     public static final String NAME = "cluster:admin/ingest/processor/grok/get";
@@ -62,11 +61,6 @@ public class GrokProcessorGetAction extends Action<GrokProcessorGetAction.Reques
         super(NAME);
     }
 
-    @Override
-    public RequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new RequestBuilder(client);
-    }
-
     @Override
     public Response newResponse() {
         return new Response(null);
@@ -79,7 +73,7 @@ public class GrokProcessorGetAction extends Action<GrokProcessorGetAction.Reques
         }
     }
 
-    public static class RequestBuilder extends ActionRequestBuilder<Request, Response, RequestBuilder> {
+    public static class RequestBuilder extends ActionRequestBuilder<Request, Response> {
         public RequestBuilder(ElasticsearchClient client) {
             super(client, GrokProcessorGetAction.INSTANCE, new Request());
         }

modules/lang-mustache/src/main/java/org/elasticsearch/script/mustache/MultiSearchTemplateAction.java

@@ -20,10 +20,8 @@
 package org.elasticsearch.script.mustache;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public class MultiSearchTemplateAction
+public class MultiSearchTemplateAction extends Action<MultiSearchTemplateRequest, MultiSearchTemplateResponse> {
-        extends Action<MultiSearchTemplateRequest, MultiSearchTemplateResponse, MultiSearchTemplateRequestBuilder> {
 
     public static final MultiSearchTemplateAction INSTANCE = new MultiSearchTemplateAction();
     public static final String NAME = "indices:data/read/msearch/template";
@@ -36,9 +34,4 @@ public class MultiSearchTemplateAction
     public MultiSearchTemplateResponse newResponse() {
         return new MultiSearchTemplateResponse();
     }
-
-    @Override
-    public MultiSearchTemplateRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new MultiSearchTemplateRequestBuilder(client, this);
-    }
 }

modules/lang-mustache/src/main/java/org/elasticsearch/script/mustache/MultiSearchTemplateRequestBuilder.java

@@ -24,7 +24,7 @@ import org.elasticsearch.action.support.IndicesOptions;
 import org.elasticsearch.client.ElasticsearchClient;
 
 public class MultiSearchTemplateRequestBuilder
-        extends ActionRequestBuilder<MultiSearchTemplateRequest, MultiSearchTemplateResponse, MultiSearchTemplateRequestBuilder> {
+        extends ActionRequestBuilder<MultiSearchTemplateRequest, MultiSearchTemplateResponse> {
 
     protected MultiSearchTemplateRequestBuilder(ElasticsearchClient client, MultiSearchTemplateAction action) {
         super(client, action, new MultiSearchTemplateRequest());

modules/lang-mustache/src/main/java/org/elasticsearch/script/mustache/SearchTemplateAction.java

@@ -20,9 +20,8 @@
 package org.elasticsearch.script.mustache;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public class SearchTemplateAction extends Action<SearchTemplateRequest, SearchTemplateResponse, SearchTemplateRequestBuilder> {
+public class SearchTemplateAction extends Action<SearchTemplateRequest, SearchTemplateResponse> {
 
     public static final SearchTemplateAction INSTANCE = new SearchTemplateAction();
     public static final String NAME = "indices:data/read/search/template";
@@ -31,11 +30,6 @@ public class SearchTemplateAction extends Action<SearchTemplateRequest, SearchTe
         super(NAME);
     }
 
-    @Override
-    public SearchTemplateRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new SearchTemplateRequestBuilder(client, this);
-    }
-
     @Override
     public SearchTemplateResponse newResponse() {
         return new SearchTemplateResponse();

modules/lang-mustache/src/main/java/org/elasticsearch/script/mustache/SearchTemplateRequestBuilder.java

@@ -27,7 +27,7 @@ import org.elasticsearch.script.ScriptType;
 import java.util.Map;
 
 public class SearchTemplateRequestBuilder
-        extends ActionRequestBuilder<SearchTemplateRequest, SearchTemplateResponse, SearchTemplateRequestBuilder> {
+        extends ActionRequestBuilder<SearchTemplateRequest, SearchTemplateResponse> {
 
     SearchTemplateRequestBuilder(ElasticsearchClient client, SearchTemplateAction action) {
         super(client, action, new SearchTemplateRequest());

modules/lang-painless/src/main/java/org/elasticsearch/painless/PainlessExecuteAction.java

@@ -62,8 +62,7 @@ import static org.elasticsearch.rest.RestRequest.Method.GET;
 import static org.elasticsearch.rest.RestRequest.Method.POST;
 import static org.elasticsearch.rest.RestStatus.OK;
 
-public class PainlessExecuteAction extends Action<PainlessExecuteAction.Request, PainlessExecuteAction.Response,
+public class PainlessExecuteAction extends Action<PainlessExecuteAction.Request, PainlessExecuteAction.Response> {
-    PainlessExecuteAction.RequestBuilder> {
 
     static final PainlessExecuteAction INSTANCE = new PainlessExecuteAction();
     private static final String NAME = "cluster:admin/scripts/painless/execute";
@@ -72,11 +71,6 @@ public class PainlessExecuteAction extends Action<PainlessExecuteAction.Request,
         super(NAME);
     }
 
-    @Override
-    public RequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new RequestBuilder(client);
-    }
-
     @Override
     public Response newResponse() {
         return new Response();
@@ -201,7 +195,7 @@ public class PainlessExecuteAction extends Action<PainlessExecuteAction.Request,
 
     }
 
-    public static class RequestBuilder extends ActionRequestBuilder<Request, Response, RequestBuilder> {
+    public static class RequestBuilder extends ActionRequestBuilder<Request, Response> {
 
         RequestBuilder(ElasticsearchClient client) {
             super(client, INSTANCE, new Request());

modules/mapper-extras/src/main/java/org/elasticsearch/index/mapper/FeatureFieldMapper.java

@@ -163,14 +163,6 @@ public class FeatureFieldMapper extends FieldMapper {
             return new TermQuery(new Term("_feature", name()));
         }
 
-        @Override
-        public Query nullValueQuery() {
-            if (nullValue() == null) {
-                return null;
-            }
-            return termQuery(nullValue(), null);
-        }
-
         @Override
         public IndexFieldData.Builder fielddataBuilder(String fullyQualifiedIndexName) {
             failIfNoDocValues();

modules/rank-eval/src/main/java/org/elasticsearch/index/rankeval/RankEvalAction.java

@@ -20,12 +20,11 @@
 package org.elasticsearch.index.rankeval;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
 /**
  * Action for explaining evaluating search ranking results.
  */
-public class RankEvalAction extends Action<RankEvalRequest, RankEvalResponse, RankEvalRequestBuilder> {
+public class RankEvalAction extends Action<RankEvalRequest, RankEvalResponse> {
 
     public static final RankEvalAction INSTANCE = new RankEvalAction();
     public static final String NAME = "indices:data/read/rank_eval";
@@ -34,11 +33,6 @@ public class RankEvalAction extends Action<RankEvalRequest, RankEvalResponse, Ra
         super(NAME);
     }
 
-    @Override
-    public RankEvalRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new RankEvalRequestBuilder(client, this, new RankEvalRequest());
-    }
-
     @Override
     public RankEvalResponse newResponse() {
         return new RankEvalResponse();

modules/rank-eval/src/main/java/org/elasticsearch/index/rankeval/RankEvalRequestBuilder.java

@@ -23,9 +23,9 @@ import org.elasticsearch.action.Action;
 import org.elasticsearch.action.ActionRequestBuilder;
 import org.elasticsearch.client.ElasticsearchClient;
 
-public class RankEvalRequestBuilder extends ActionRequestBuilder<RankEvalRequest, RankEvalResponse, RankEvalRequestBuilder> {
+public class RankEvalRequestBuilder extends ActionRequestBuilder<RankEvalRequest, RankEvalResponse> {
 
-    public RankEvalRequestBuilder(ElasticsearchClient client, Action<RankEvalRequest, RankEvalResponse, RankEvalRequestBuilder> action,
+    public RankEvalRequestBuilder(ElasticsearchClient client, Action<RankEvalRequest, RankEvalResponse> action,
             RankEvalRequest request) {
         super(client, action, request);
     }

modules/reindex/src/main/java/org/elasticsearch/index/reindex/BulkByScrollParallelizationHelper.java

@@ -61,7 +61,7 @@ class BulkByScrollParallelizationHelper {
     static <Request extends AbstractBulkByScrollRequest<Request>> void startSlicedAction(
             Request request,
             BulkByScrollTask task,
-            Action<Request, BulkByScrollResponse, ?> action,
+            Action<Request, BulkByScrollResponse> action,
             ActionListener<BulkByScrollResponse> listener,
             Client client,
             DiscoveryNode node,
@@ -85,7 +85,7 @@ class BulkByScrollParallelizationHelper {
     private static <Request extends AbstractBulkByScrollRequest<Request>> void sliceConditionally(
             Request request,
             BulkByScrollTask task,
-            Action<Request, BulkByScrollResponse, ?> action,
+            Action<Request, BulkByScrollResponse> action,
             ActionListener<BulkByScrollResponse> listener,
             Client client,
             DiscoveryNode node,
@@ -118,7 +118,7 @@ class BulkByScrollParallelizationHelper {
 
     private static <Request extends AbstractBulkByScrollRequest<Request>> void sendSubRequests(
             Client client,
-            Action<Request, BulkByScrollResponse, ?> action,
+            Action<Request, BulkByScrollResponse> action,
             String localNodeId,
             BulkByScrollTask task,
             Request request,

modules/reindex/src/main/java/org/elasticsearch/index/reindex/RethrottleAction.java

@@ -21,9 +21,8 @@ package org.elasticsearch.index.reindex;
 
 import org.elasticsearch.action.Action;
 import org.elasticsearch.action.admin.cluster.node.tasks.list.ListTasksResponse;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public class RethrottleAction extends Action<RethrottleRequest, ListTasksResponse, RethrottleRequestBuilder> {
+public class RethrottleAction extends Action<RethrottleRequest, ListTasksResponse> {
     public static final RethrottleAction INSTANCE = new RethrottleAction();
     public static final String NAME = "cluster:admin/reindex/rethrottle";
 
@@ -31,11 +30,6 @@ public class RethrottleAction extends Action<RethrottleRequest, ListTasksRespons
         super(NAME);
     }
 
-    @Override
-    public RethrottleRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new RethrottleRequestBuilder(client, this);
-    }
-
     @Override
     public ListTasksResponse newResponse() {
         return new ListTasksResponse();

modules/reindex/src/main/java/org/elasticsearch/index/reindex/RethrottleRequestBuilder.java

@@ -29,7 +29,7 @@ import org.elasticsearch.client.ElasticsearchClient;
  */
 public class RethrottleRequestBuilder extends TasksRequestBuilder<RethrottleRequest, ListTasksResponse, RethrottleRequestBuilder> {
     public RethrottleRequestBuilder(ElasticsearchClient client,
-            Action<RethrottleRequest, ListTasksResponse, RethrottleRequestBuilder> action) {
+            Action<RethrottleRequest, ListTasksResponse> action) {
         super(client, action, new RethrottleRequest());
     }
 

modules/reindex/src/test/java/org/elasticsearch/client/documentation/ReindexDocumentationIT.java

@@ -27,10 +27,12 @@ import org.elasticsearch.index.query.QueryBuilders;
 import org.elasticsearch.index.reindex.BulkByScrollResponse;
 import org.elasticsearch.index.reindex.BulkByScrollTask;
 import org.elasticsearch.index.reindex.DeleteByQueryAction;
+import org.elasticsearch.index.reindex.DeleteByQueryRequestBuilder;
 import org.elasticsearch.index.reindex.ReindexAction;
 import org.elasticsearch.index.reindex.ReindexRequest;
 import org.elasticsearch.index.reindex.ReindexRequestBuilder;
 import org.elasticsearch.index.reindex.RethrottleAction;
+import org.elasticsearch.index.reindex.RethrottleRequestBuilder;
 import org.elasticsearch.index.reindex.UpdateByQueryAction;
 import org.elasticsearch.index.reindex.UpdateByQueryRequestBuilder;
 import org.elasticsearch.script.Script;
@@ -47,7 +49,7 @@ public class ReindexDocumentationIT extends ESIntegTestCase {
     public void reindex() {
         Client client = client();
         // tag::reindex1
-        BulkByScrollResponse response = ReindexAction.INSTANCE.newRequestBuilder(client)
+        BulkByScrollResponse response = new ReindexRequestBuilder(client, ReindexAction.INSTANCE)
             .destination("target_index")
             .filter(QueryBuilders.matchQuery("category", "xzy")) // <1>
             .get();
@@ -58,14 +60,14 @@ public class ReindexDocumentationIT extends ESIntegTestCase {
         Client client = client();
         {
             // tag::update-by-query
-            UpdateByQueryRequestBuilder updateByQuery = UpdateByQueryAction.INSTANCE.newRequestBuilder(client);
+            UpdateByQueryRequestBuilder updateByQuery = new UpdateByQueryRequestBuilder(client, UpdateByQueryAction.INSTANCE);
             updateByQuery.source("source_index").abortOnVersionConflict(false);
             BulkByScrollResponse response = updateByQuery.get();
             // end::update-by-query
         }
         {
             // tag::update-by-query-filter
-            UpdateByQueryRequestBuilder updateByQuery = UpdateByQueryAction.INSTANCE.newRequestBuilder(client);
+            UpdateByQueryRequestBuilder updateByQuery = new UpdateByQueryRequestBuilder(client, UpdateByQueryAction.INSTANCE);
             updateByQuery.source("source_index")
                 .filter(QueryBuilders.termQuery("level", "awesome"))
                 .size(1000)
@@ -75,7 +77,7 @@ public class ReindexDocumentationIT extends ESIntegTestCase {
         }
         {
             // tag::update-by-query-size
-            UpdateByQueryRequestBuilder updateByQuery = UpdateByQueryAction.INSTANCE.newRequestBuilder(client);
+            UpdateByQueryRequestBuilder updateByQuery = new UpdateByQueryRequestBuilder(client, UpdateByQueryAction.INSTANCE);
             updateByQuery.source("source_index")
                 .source().setSize(500);
             BulkByScrollResponse response = updateByQuery.get();
@@ -83,7 +85,7 @@ public class ReindexDocumentationIT extends ESIntegTestCase {
         }
         {
             // tag::update-by-query-sort
-            UpdateByQueryRequestBuilder updateByQuery = UpdateByQueryAction.INSTANCE.newRequestBuilder(client);
+            UpdateByQueryRequestBuilder updateByQuery = new UpdateByQueryRequestBuilder(client, UpdateByQueryAction.INSTANCE);
             updateByQuery.source("source_index").size(100)
                 .source().addSort("cat", SortOrder.DESC);
             BulkByScrollResponse response = updateByQuery.get();
@@ -91,7 +93,7 @@ public class ReindexDocumentationIT extends ESIntegTestCase {
         }
         {
             // tag::update-by-query-script
-            UpdateByQueryRequestBuilder updateByQuery = UpdateByQueryAction.INSTANCE.newRequestBuilder(client);
+            UpdateByQueryRequestBuilder updateByQuery = new UpdateByQueryRequestBuilder(client, UpdateByQueryAction.INSTANCE);
             updateByQuery.source("source_index")
                 .script(new Script(
                     ScriptType.INLINE,
@@ -108,21 +110,21 @@ public class ReindexDocumentationIT extends ESIntegTestCase {
         }
         {
             // tag::update-by-query-multi-index
-            UpdateByQueryRequestBuilder updateByQuery = UpdateByQueryAction.INSTANCE.newRequestBuilder(client);
+            UpdateByQueryRequestBuilder updateByQuery = new UpdateByQueryRequestBuilder(client, UpdateByQueryAction.INSTANCE);
             updateByQuery.source("foo", "bar").source().setTypes("a", "b");
             BulkByScrollResponse response = updateByQuery.get();
             // end::update-by-query-multi-index
         }
         {
             // tag::update-by-query-routing
-            UpdateByQueryRequestBuilder updateByQuery = UpdateByQueryAction.INSTANCE.newRequestBuilder(client);
+            UpdateByQueryRequestBuilder updateByQuery = new UpdateByQueryRequestBuilder(client, UpdateByQueryAction.INSTANCE);
             updateByQuery.source().setRouting("cat");
             BulkByScrollResponse response = updateByQuery.get();
             // end::update-by-query-routing
         }
         {
             // tag::update-by-query-pipeline
-            UpdateByQueryRequestBuilder updateByQuery = UpdateByQueryAction.INSTANCE.newRequestBuilder(client);
+            UpdateByQueryRequestBuilder updateByQuery = new UpdateByQueryRequestBuilder(client, UpdateByQueryAction.INSTANCE);
             updateByQuery.setPipeline("hurray");
             BulkByScrollResponse response = updateByQuery.get();
             // end::update-by-query-pipeline
@@ -156,7 +158,7 @@ public class ReindexDocumentationIT extends ESIntegTestCase {
         {
             TaskId taskId = null;
             // tag::update-by-query-rethrottle
-            RethrottleAction.INSTANCE.newRequestBuilder(client)
+            new RethrottleRequestBuilder(client, RethrottleAction.INSTANCE)
                 .setTaskId(taskId)
                 .setRequestsPerSecond(2.0f)
                 .get();
@@ -167,7 +169,7 @@ public class ReindexDocumentationIT extends ESIntegTestCase {
     public void deleteByQuery() {
         Client client = client();
         // tag::delete-by-query-sync
-        BulkByScrollResponse response = DeleteByQueryAction.INSTANCE.newRequestBuilder(client)
+        BulkByScrollResponse response = new DeleteByQueryRequestBuilder(client, DeleteByQueryAction.INSTANCE)
             .filter(QueryBuilders.matchQuery("gender", "male")) // <1>
             .source("persons")                                  // <2>
             .get();                                             // <3>
@@ -175,7 +177,7 @@ public class ReindexDocumentationIT extends ESIntegTestCase {
         // end::delete-by-query-sync
 
         // tag::delete-by-query-async
-        DeleteByQueryAction.INSTANCE.newRequestBuilder(client)
+        new DeleteByQueryRequestBuilder(client, DeleteByQueryAction.INSTANCE)
             .filter(QueryBuilders.matchQuery("gender", "male"))     // <1>
             .source("persons")                                      // <2>
             .execute(new ActionListener<BulkByScrollResponse>() {   // <3>

modules/reindex/src/test/java/org/elasticsearch/index/reindex/AsyncBulkByScrollActionTests.java

@@ -744,8 +744,8 @@ public class AsyncBulkByScrollActionTests extends ESTestCase {
         @Override
         @SuppressWarnings("unchecked")
         protected <Request extends ActionRequest, Response extends ActionResponse,
-                RequestBuilder extends ActionRequestBuilder<Request, Response, RequestBuilder>> void doExecute(
+                RequestBuilder extends ActionRequestBuilder<Request, Response>> void doExecute(
-                Action<Request, Response, RequestBuilder> action, Request request, ActionListener<Response> listener) {
+                Action<Request, Response> action, Request request, ActionListener<Response> listener) {
             if (false == expectedHeaders.equals(threadPool().getThreadContext().getHeaders())) {
                 listener.onFailure(
                         new RuntimeException("Expected " + expectedHeaders + " but got " + threadPool().getThreadContext().getHeaders()));

modules/reindex/src/test/java/org/elasticsearch/index/reindex/ReindexFromRemoteWithAuthTests.java

@@ -109,13 +109,13 @@ public class ReindexFromRemoteWithAuthTests extends ESSingleNodeTestCase {
     }
 
     public void testReindexFromRemoteWithAuthentication() throws Exception {
-        ReindexRequestBuilder request = ReindexAction.INSTANCE.newRequestBuilder(client()).source("source").destination("dest")
+        ReindexRequestBuilder request = new ReindexRequestBuilder(client(), ReindexAction.INSTANCE).source("source").destination("dest")
                 .setRemoteInfo(newRemoteInfo("Aladdin", "open sesame", emptyMap()));
         assertThat(request.get(), matcher().created(1));
     }
 
     public void testReindexSendsHeaders() throws Exception {
-        ReindexRequestBuilder request = ReindexAction.INSTANCE.newRequestBuilder(client()).source("source").destination("dest")
+        ReindexRequestBuilder request = new ReindexRequestBuilder(client(), ReindexAction.INSTANCE).source("source").destination("dest")
                 .setRemoteInfo(newRemoteInfo(null, null, singletonMap(TestFilter.EXAMPLE_HEADER, "doesn't matter")));
         ElasticsearchStatusException e = expectThrows(ElasticsearchStatusException.class, () -> request.get());
         assertEquals(RestStatus.BAD_REQUEST, e.status());
@@ -123,7 +123,7 @@ public class ReindexFromRemoteWithAuthTests extends ESSingleNodeTestCase {
     }
 
     public void testReindexWithoutAuthenticationWhenRequired() throws Exception {
-        ReindexRequestBuilder request = ReindexAction.INSTANCE.newRequestBuilder(client()).source("source").destination("dest")
+        ReindexRequestBuilder request = new ReindexRequestBuilder(client(), ReindexAction.INSTANCE).source("source").destination("dest")
                 .setRemoteInfo(newRemoteInfo(null, null, emptyMap()));
         ElasticsearchStatusException e = expectThrows(ElasticsearchStatusException.class, () -> request.get());
         assertEquals(RestStatus.UNAUTHORIZED, e.status());
@@ -132,7 +132,7 @@ public class ReindexFromRemoteWithAuthTests extends ESSingleNodeTestCase {
     }
 
     public void testReindexWithBadAuthentication() throws Exception {
-        ReindexRequestBuilder request = ReindexAction.INSTANCE.newRequestBuilder(client()).source("source").destination("dest")
+        ReindexRequestBuilder request = new ReindexRequestBuilder(client(), ReindexAction.INSTANCE).source("source").destination("dest")
                 .setRemoteInfo(newRemoteInfo("junk", "auth", emptyMap()));
         ElasticsearchStatusException e = expectThrows(ElasticsearchStatusException.class, () -> request.get());
         assertThat(e.getMessage(), containsString("\"reason\":\"Bad Authorization\""));

modules/reindex/src/test/java/org/elasticsearch/index/reindex/ReindexTestCase.java

@@ -47,19 +47,19 @@ public abstract class ReindexTestCase extends ESIntegTestCase {
     }
 
     protected ReindexRequestBuilder reindex() {
-        return ReindexAction.INSTANCE.newRequestBuilder(client());
+        return new ReindexRequestBuilder(client(), ReindexAction.INSTANCE);
     }
 
     protected UpdateByQueryRequestBuilder updateByQuery() {
-        return UpdateByQueryAction.INSTANCE.newRequestBuilder(client());
+        return new UpdateByQueryRequestBuilder(client(), UpdateByQueryAction.INSTANCE);
     }
 
     protected DeleteByQueryRequestBuilder deleteByQuery() {
-        return DeleteByQueryAction.INSTANCE.newRequestBuilder(client());
+        return new DeleteByQueryRequestBuilder(client(), DeleteByQueryAction.INSTANCE);
     }
 
     protected RethrottleRequestBuilder rethrottle() {
-        return RethrottleAction.INSTANCE.newRequestBuilder(client());
+        return new RethrottleRequestBuilder(client(), RethrottleAction.INSTANCE);
     }
 
     public static BulkIndexByScrollResponseMatcher matcher() {

modules/reindex/src/test/java/org/elasticsearch/index/reindex/RetryTests.java

@@ -106,7 +106,7 @@ public class RetryTests extends ESIntegTestCase {
     public void testReindex() throws Exception {
         testCase(
                 ReindexAction.NAME,
-                client -> ReindexAction.INSTANCE.newRequestBuilder(client).source("source").destination("dest"),
+                client -> new ReindexRequestBuilder(client, ReindexAction.INSTANCE).source("source").destination("dest"),
                 matcher().created(DOC_COUNT));
     }
 
@@ -127,7 +127,7 @@ public class RetryTests extends ESIntegTestCase {
             TransportAddress address = masterNode.getHttp().getAddress().publishAddress();
             RemoteInfo remote = new RemoteInfo("http", address.getAddress(), address.getPort(), new BytesArray("{\"match_all\":{}}"), null,
                     null, emptyMap(), RemoteInfo.DEFAULT_SOCKET_TIMEOUT, RemoteInfo.DEFAULT_CONNECT_TIMEOUT);
-            ReindexRequestBuilder request = ReindexAction.INSTANCE.newRequestBuilder(client).source("source").destination("dest")
+            ReindexRequestBuilder request = new ReindexRequestBuilder(client, ReindexAction.INSTANCE).source("source").destination("dest")
                     .setRemoteInfo(remote);
             return request;
         };
@@ -135,12 +135,12 @@ public class RetryTests extends ESIntegTestCase {
     }
 
     public void testUpdateByQuery() throws Exception {
-        testCase(UpdateByQueryAction.NAME, client -> UpdateByQueryAction.INSTANCE.newRequestBuilder(client).source("source"),
+        testCase(UpdateByQueryAction.NAME, client -> new UpdateByQueryRequestBuilder(client, UpdateByQueryAction.INSTANCE).source("source"),
                 matcher().updated(DOC_COUNT));
     }
 
     public void testDeleteByQuery() throws Exception {
-        testCase(DeleteByQueryAction.NAME, client -> DeleteByQueryAction.INSTANCE.newRequestBuilder(client).source("source")
+        testCase(DeleteByQueryAction.NAME, client -> new DeleteByQueryRequestBuilder(client, DeleteByQueryAction.INSTANCE).source("source")
                 .filter(QueryBuilders.matchAllQuery()), matcher().deleted(DOC_COUNT));
     }
 

plugins/analysis-icu/src/main/java/org/elasticsearch/index/mapper/ICUCollationKeywordFieldMapper.java

@@ -135,14 +135,6 @@ public class ICUCollationKeywordFieldMapper extends FieldMapper {
             }
         }
 
-        @Override
-        public Query nullValueQuery() {
-            if (nullValue() == null) {
-                return null;
-            }
-            return termQuery(nullValue(), null);
-        }
-
         @Override
         public IndexFieldData.Builder fielddataBuilder(String fullyQualifiedIndexName) {
             failIfNoDocValues();

qa/multi-cluster-search/src/test/resources/rest-api-spec/test/multi_cluster/50_missing.yml

@@ -1,7 +1,7 @@
 ---
 "Search with missing remote index pattern":
   - do:
-      catch: "request"
+      catch: "missing"
       search:
         index: "my_remote_cluster:foo"
 
@@ -34,7 +34,7 @@
   - match: { aggregations.cluster.buckets.0.doc_count: 6 }
 
   - do:
-      catch: "request"
+      catch: "missing"
       search:
         index: "my_remote_cluster:test_index,my_remote_cluster:foo"
         body:

qa/smoke-test-http/src/test/java/org/elasticsearch/http/ContextAndHeaderTransportIT.java

@@ -31,6 +31,7 @@ import org.elasticsearch.action.support.ActionFilter;
 import org.elasticsearch.action.termvectors.MultiTermVectorsRequest;
 import org.elasticsearch.client.Client;
 import org.elasticsearch.client.Request;
+import org.elasticsearch.client.RequestOptions;
 import org.elasticsearch.client.Response;
 import org.elasticsearch.cluster.service.ClusterService;
 import org.elasticsearch.common.Strings;
@@ -221,8 +222,10 @@ public class ContextAndHeaderTransportIT extends HttpSmokeTestCase {
     public void testThatRelevantHttpHeadersBecomeRequestHeaders() throws IOException {
         final String IRRELEVANT_HEADER = "SomeIrrelevantHeader";
         Request request = new Request("GET", "/" + queryIndex + "/_search");
-        request.addHeader(CUSTOM_HEADER, randomHeaderValue);
+        RequestOptions.Builder options = request.getOptions().toBuilder();
-        request.addHeader(IRRELEVANT_HEADER, randomHeaderValue);
+        options.addHeader(CUSTOM_HEADER, randomHeaderValue);
+        options.addHeader(IRRELEVANT_HEADER, randomHeaderValue);
+        request.setOptions(options);
         Response response = getRestClient().performRequest(request);
         assertThat(response.getStatusLine().getStatusCode(), equalTo(200));
         List<RequestAndHeaders> searchRequests = getRequests(SearchRequest.class);

qa/smoke-test-http/src/test/java/org/elasticsearch/http/CorsNotSetIT.java

@@ -20,6 +20,7 @@
 package org.elasticsearch.http;
 
 import org.elasticsearch.client.Request;
+import org.elasticsearch.client.RequestOptions;
 import org.elasticsearch.client.Response;
 
 import java.io.IOException;
@@ -32,8 +33,10 @@ public class CorsNotSetIT extends HttpSmokeTestCase {
     public void testCorsSettingDefaultBehaviourDoesNotReturnAnything() throws IOException {
         String corsValue = "http://localhost:9200";
         Request request = new Request("GET", "/");
-        request.addHeader("User-Agent", "Mozilla Bar");
+        RequestOptions.Builder options = request.getOptions().toBuilder();
-        request.addHeader("Origin", corsValue);
+        options.addHeader("User-Agent", "Mozilla Bar");
+        options.addHeader("Origin", corsValue);
+        request.setOptions(options);
         Response response = getRestClient().performRequest(request);
         assertThat(response.getStatusLine().getStatusCode(), is(200));
         assertThat(response.getHeader("Access-Control-Allow-Origin"), nullValue());

qa/smoke-test-http/src/test/java/org/elasticsearch/http/CorsRegexIT.java

@@ -19,6 +19,7 @@
 package org.elasticsearch.http;
 
 import org.elasticsearch.client.Request;
+import org.elasticsearch.client.RequestOptions;
 import org.elasticsearch.client.Response;
 import org.elasticsearch.client.ResponseException;
 import org.elasticsearch.common.settings.Settings;
@@ -55,16 +56,20 @@ public class CorsRegexIT extends HttpSmokeTestCase {
         {
             String corsValue = "http://localhost:9200";
             Request request = new Request("GET", "/");
-            request.addHeader("User-Agent", "Mozilla Bar");
+            RequestOptions.Builder options = request.getOptions().toBuilder();
-            request.addHeader("Origin", corsValue);
+            options.addHeader("User-Agent", "Mozilla Bar");
+            options.addHeader("Origin", corsValue);
+            request.setOptions(options);
             Response response = getRestClient().performRequest(request);
             assertResponseWithOriginHeader(response, corsValue);
         }
         {
             String corsValue = "https://localhost:9201";
             Request request = new Request("GET", "/");
-            request.addHeader("User-Agent", "Mozilla Bar");
+            RequestOptions.Builder options = request.getOptions().toBuilder();
-            request.addHeader("Origin", corsValue);
+            options.addHeader("User-Agent", "Mozilla Bar");
+            options.addHeader("Origin", corsValue);
+            request.setOptions(options);
             Response response = getRestClient().performRequest(request);
             assertResponseWithOriginHeader(response, corsValue);
             assertThat(response.getHeader("Access-Control-Allow-Credentials"), is("true"));
@@ -73,8 +78,10 @@ public class CorsRegexIT extends HttpSmokeTestCase {
 
     public void testThatRegularExpressionReturnsForbiddenOnNonMatch() throws IOException {
         Request request = new Request("GET", "/");
-        request.addHeader("User-Agent", "Mozilla Bar");
+        RequestOptions.Builder options = request.getOptions().toBuilder();
-        request.addHeader("Origin", "http://evil-host:9200");
+        options.addHeader("User-Agent", "Mozilla Bar");
+        options.addHeader("Origin", "http://evil-host:9200");
+        request.setOptions(options);
         try {
             getRestClient().performRequest(request);
             fail("request should have failed");
@@ -88,7 +95,9 @@ public class CorsRegexIT extends HttpSmokeTestCase {
 
     public void testThatSendingNoOriginHeaderReturnsNoAccessControlHeader() throws IOException {
         Request request = new Request("GET", "/");
-        request.addHeader("User-Agent", "Mozilla Bar");
+        RequestOptions.Builder options = request.getOptions().toBuilder();
+        options.addHeader("User-Agent", "Mozilla Bar");
+        request.setOptions(options);
         Response response = getRestClient().performRequest(request);
         assertThat(response.getStatusLine().getStatusCode(), is(200));
         assertThat(response.getHeader("Access-Control-Allow-Origin"), nullValue());
@@ -103,9 +112,11 @@ public class CorsRegexIT extends HttpSmokeTestCase {
     public void testThatPreFlightRequestWorksOnMatch() throws IOException {
         String corsValue = "http://localhost:9200";
         Request request = new Request("OPTIONS", "/");
-        request.addHeader("User-Agent", "Mozilla Bar");
+        RequestOptions.Builder options = request.getOptions().toBuilder();
-        request.addHeader("Origin", corsValue);
+        options.addHeader("User-Agent", "Mozilla Bar");
-        request.addHeader("Access-Control-Request-Method", "GET");
+        options.addHeader("Origin", corsValue);
+        options.addHeader("Access-Control-Request-Method", "GET");
+        request.setOptions(options);
         Response response = getRestClient().performRequest(request);
         assertResponseWithOriginHeader(response, corsValue);
         assertNotNull(response.getHeader("Access-Control-Allow-Methods"));
@@ -114,9 +125,11 @@ public class CorsRegexIT extends HttpSmokeTestCase {
     public void testThatPreFlightRequestReturnsNullOnNonMatch() throws IOException {
         String corsValue = "http://evil-host:9200";
         Request request = new Request("OPTIONS", "/");
-        request.addHeader("User-Agent", "Mozilla Bar");
+        RequestOptions.Builder options = request.getOptions().toBuilder();
-        request.addHeader("Origin", corsValue);
+        options.addHeader("User-Agent", "Mozilla Bar");
-        request.addHeader("Access-Control-Request-Method", "GET");
+        options.addHeader("Origin", corsValue);
+        options.addHeader("Access-Control-Request-Method", "GET");
+        request.setOptions(options);
         try {
             getRestClient().performRequest(request);
             fail("request should have failed");

qa/smoke-test-http/src/test/java/org/elasticsearch/http/HttpCompressionIT.java

@@ -20,6 +20,7 @@ package org.elasticsearch.http;
 
 import org.apache.http.HttpHeaders;
 import org.elasticsearch.client.Request;
+import org.elasticsearch.client.RequestOptions;
 import org.elasticsearch.client.Response;
 import org.elasticsearch.test.rest.ESRestTestCase;
 
@@ -38,7 +39,9 @@ public class HttpCompressionIT extends ESRestTestCase {
 
     public void testCompressesResponseIfRequested() throws IOException {
         Request request = new Request("GET", "/");
-        request.addHeader(HttpHeaders.ACCEPT_ENCODING, GZIP_ENCODING);
+        RequestOptions.Builder options = request.getOptions().toBuilder();
+        options.addHeader(HttpHeaders.ACCEPT_ENCODING, GZIP_ENCODING);
+        request.setOptions(options);
         Response response = client().performRequest(request);
         assertEquals(200, response.getStatusLine().getStatusCode());
         assertEquals(GZIP_ENCODING, response.getHeader(HttpHeaders.CONTENT_ENCODING));

qa/smoke-test-http/src/test/java/org/elasticsearch/http/NoHandlerIT.java

@@ -21,6 +21,7 @@ package org.elasticsearch.http;
 
 import org.apache.http.util.EntityUtils;
 import org.elasticsearch.client.Request;
+import org.elasticsearch.client.RequestOptions;
 import org.elasticsearch.client.Response;
 import org.elasticsearch.client.ResponseException;
 
@@ -46,7 +47,9 @@ public class NoHandlerIT extends HttpSmokeTestCase {
     private void runTestNoHandlerRespectsAcceptHeader(
             final String accept, final String contentType, final String expect) throws IOException {
         Request request = new Request("GET", "/foo/bar/baz/qux/quux");
-        request.addHeader("Accept", accept);
+        RequestOptions.Builder options = request.getOptions().toBuilder();
+        options.addHeader("Accept", accept);
+        request.setOptions(options);
         final ResponseException e = expectThrows(ResponseException.class,
                         () -> getRestClient().performRequest(request));
 

qa/smoke-test-http/src/test/java/org/elasticsearch/http/ResponseHeaderPluginIT.java

@@ -19,6 +19,7 @@
 package org.elasticsearch.http;
 
 import org.elasticsearch.client.Request;
+import org.elasticsearch.client.RequestOptions;
 import org.elasticsearch.client.Response;
 import org.elasticsearch.client.ResponseException;
 import org.elasticsearch.plugins.Plugin;
@@ -61,7 +62,9 @@ public class ResponseHeaderPluginIT extends HttpSmokeTestCase {
         }
 
         Request request = new Request("GET", "/_protected");
-        request.addHeader("Secret", "password");
+        RequestOptions.Builder options = request.getOptions().toBuilder();
+        options.addHeader("Secret", "password");
+        request.setOptions(options);
         Response authResponse = getRestClient().performRequest(request);
         assertThat(authResponse.getStatusLine().getStatusCode(), equalTo(200));
         assertThat(authResponse.getHeader("Secret"), equalTo("granted"));

rest-api-spec/src/main/resources/rest-api-spec/test/snapshot.get_repository/10_basic.yml

@@ -51,9 +51,6 @@ setup:
 
 ---
 "Verify created repository":
-  - skip:
-      version:     "all"
-      reason:      AwaitsFix for https://github.com/elastic/elasticsearch/issues/30807
   - do:
       snapshot.verify_repository:
         repository: test_repo_get_2

rest-api-spec/src/main/resources/rest-api-spec/test/suggest/30_context.yml

@@ -336,16 +336,80 @@ setup:
   - length: { suggest.result.0.options: 1  }
   - match:  { suggest.result.0.options.0.text: "foo" }
 
+---
+"Indexing and Querying without contexts is deprecated":
+  - skip:
+      version: " - 6.99.99"
+      reason: this feature was deprecated in 7.0
+      features: "warnings"
+
   - do:
+      index:
+        index: test
+        type:  test
+        id:    1
+        body:
+          suggest_context:
+            input: "foo"
+            contexts:
+              color: "red"
+          suggest_multi_contexts:
+            input: "bar"
+            contexts:
+              color: "blue"
+
+  - do:
+      warnings:
+        - "The ability to index a suggestion with no context on a context enabled completion field is deprecated and will be removed in the next major release."
+      index:
+        index: test
+        type:  test
+        id:    2
+        body:
+          suggest_context:
+            input: "foo"
+
+  - do:
+      indices.refresh: {}
+      
+  - do:
+      warnings:
+        - "The ability to query with no context on a context enabled completion field is deprecated and will be removed in the next major release."
       search:
         body:
           suggest:
             result:
               text: "foo"
               completion:
-                skip_duplicates: true
                 field: suggest_context
 
   - length: { suggest.result: 1  }
-  - length: { suggest.result.0.options: 1  }
+
-  - match:  { suggest.result.0.options.0.text: "foo" }
+  - do:
+      warnings:
+        - "The ability to query with no context on a context enabled completion field is deprecated and will be removed in the next major release."
+      search:
+        body:
+          suggest:
+            result:
+              text: "foo"
+              completion:
+                field: suggest_context
+                contexts: {}
+
+  - length: { suggest.result: 1  }
+
+  - do:
+      warnings:
+          - "The ability to query with no context on a context enabled completion field is deprecated and will be removed in the next major release."
+      search:
+        body:
+          suggest:
+            result:
+              text: "foo"
+              completion:
+                field: suggest_multi_contexts
+                contexts:
+                  location: []
+
+  - length: { suggest.result: 1  }

rest-api-spec/src/main/resources/rest-api-spec/test/suggest/40_typed_keys.yml

@@ -19,6 +19,8 @@ setup:
                           "type" : "category"
 
   - do:
+      warnings:
+        - "The ability to index a suggestion with no context on a context enabled completion field is deprecated and will be removed in the next major release."
       bulk:
         refresh: true
         index: test
@@ -31,8 +33,14 @@ setup:
 
 ---
 "Test typed keys parameter for suggesters":
+  - skip:
+      version: " - 6.99.99"
+      reason: queying a context suggester with no context was deprecated in 7.0
+      features: "warnings"
 
   - do:
+      warnings:
+        - "The ability to query with no context on a context enabled completion field is deprecated and will be removed in the next major release."
       search:
         typed_keys: true
         body:

server/src/main/java/org/apache/lucene/queries/ExtendedCommonTermsQuery.java

@@ -19,12 +19,8 @@
 
 package org.apache.lucene.queries;
 
-import org.apache.lucene.index.Term;
-import org.apache.lucene.index.TermContext;
 import org.apache.lucene.search.BooleanClause.Occur;
-import org.apache.lucene.search.Query;
 import org.elasticsearch.common.lucene.search.Queries;
-import org.elasticsearch.index.mapper.MappedFieldType;
 
 /**
  * Extended version of {@link CommonTermsQuery} that allows to pass in a
@@ -33,11 +29,8 @@ import org.elasticsearch.index.mapper.MappedFieldType;
  */
 public class ExtendedCommonTermsQuery extends CommonTermsQuery {
 
-    private final MappedFieldType fieldType;
+    public ExtendedCommonTermsQuery(Occur highFreqOccur, Occur lowFreqOccur, float maxTermFrequency) {
-
-    public ExtendedCommonTermsQuery(Occur highFreqOccur, Occur lowFreqOccur, float maxTermFrequency, MappedFieldType fieldType) {
         super(highFreqOccur, lowFreqOccur, maxTermFrequency);
-        this.fieldType = fieldType;
     }
 
     private String lowFreqMinNumShouldMatchSpec;
@@ -80,16 +73,4 @@ public class ExtendedCommonTermsQuery extends CommonTermsQuery {
         return this.maxTermFrequency;
     }
 
-    @Override
-    protected Query newTermQuery(Term term, TermContext context) {
-        if (fieldType == null) {
-            return super.newTermQuery(term, context);
-        }
-        final Query query = fieldType.queryStringTermQuery(term);
-        if (query == null) {
-            return super.newTermQuery(term, context);
-        } else {
-            return query;
-        }
-    }
 }

server/src/main/java/org/elasticsearch/ElasticsearchException.java

@@ -269,7 +269,6 @@ public class ElasticsearchException extends RuntimeException implements ToXConte
         }
     }
 
-
     /**
      * Retrieve the innermost cause of this exception, if none, returns the current exception.
      */
@@ -292,7 +291,7 @@ public class ElasticsearchException extends RuntimeException implements ToXConte
             out.writeMapOfLists(headers, StreamOutput::writeString, StreamOutput::writeString);
             out.writeMapOfLists(metadata, StreamOutput::writeString, StreamOutput::writeString);
         } else {
-            HashMap<String, List<String>> finalHeaders = new HashMap<>(headers.size() + metadata.size());
+            Map<String, List<String>> finalHeaders = new HashMap<>(headers.size() + metadata.size());
             finalHeaders.putAll(headers);
             finalHeaders.putAll(metadata);
             out.writeMapOfLists(finalHeaders, StreamOutput::writeString, StreamOutput::writeString);

server/src/main/java/org/elasticsearch/action/Action.java

@@ -19,20 +19,13 @@
 
 package org.elasticsearch.action;
 
-import org.elasticsearch.client.ElasticsearchClient;
-
 /**
  * Base action. Supports building the <code>Request</code> through a <code>RequestBuilder</code>.
  */
-public abstract class Action<Request extends ActionRequest, Response extends ActionResponse, RequestBuilder extends ActionRequestBuilder<Request, Response, RequestBuilder>>
+public abstract class Action<Request extends ActionRequest, Response extends ActionResponse>
         extends GenericAction<Request, Response> {
 
     protected Action(String name) {
         super(name);
     }
-
-    /**
-     * Creates a new request builder given the client provided as argument
-     */
-    public abstract RequestBuilder newRequestBuilder(ElasticsearchClient client);
 }

server/src/main/java/org/elasticsearch/action/ActionRequestBuilder.java

@@ -24,14 +24,13 @@ import org.elasticsearch.common.unit.TimeValue;
 
 import java.util.Objects;
 
-public abstract class ActionRequestBuilder<Request extends ActionRequest, Response extends ActionResponse,
+public abstract class ActionRequestBuilder<Request extends ActionRequest, Response extends ActionResponse> {
-        RequestBuilder extends ActionRequestBuilder<Request, Response, RequestBuilder>> {
 
-    protected final Action<Request, Response, RequestBuilder> action;
+    protected final Action<Request, Response> action;
     protected final Request request;
     protected final ElasticsearchClient client;
 
-    protected ActionRequestBuilder(ElasticsearchClient client, Action<Request, Response, RequestBuilder> action, Request request) {
+    protected ActionRequestBuilder(ElasticsearchClient client, Action<Request, Response> action, Request request) {
         Objects.requireNonNull(action, "action must not be null");
         this.action = action;
         this.request = request;

server/src/main/java/org/elasticsearch/action/FailedNodeException.java

@@ -22,6 +22,7 @@ package org.elasticsearch.action;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
+import org.elasticsearch.common.xcontent.XContentBuilder;
 
 import java.io.IOException;
 
@@ -48,4 +49,9 @@ public class FailedNodeException extends ElasticsearchException {
         super.writeTo(out);
         out.writeOptionalString(nodeId);
     }
+
+    @Override
+    protected void metadataToXContent(XContentBuilder builder, Params params) throws IOException {
+        builder.field("node_id", nodeId);
+    }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/allocation/ClusterAllocationExplainAction.java

@@ -25,9 +25,7 @@ import org.elasticsearch.client.ElasticsearchClient;
 /**
  * Action for explaining shard allocation for a shard in the cluster
  */
-public class ClusterAllocationExplainAction extends Action<ClusterAllocationExplainRequest,
+public class ClusterAllocationExplainAction extends Action<ClusterAllocationExplainRequest, ClusterAllocationExplainResponse> {
-                                                               ClusterAllocationExplainResponse,
-                                                               ClusterAllocationExplainRequestBuilder> {
 
     public static final ClusterAllocationExplainAction INSTANCE = new ClusterAllocationExplainAction();
     public static final String NAME = "cluster:monitor/allocation/explain";
@@ -40,9 +38,4 @@ public class ClusterAllocationExplainAction extends Action<ClusterAllocationExpl
     public ClusterAllocationExplainResponse newResponse() {
         return new ClusterAllocationExplainResponse();
     }
-
-    @Override
-    public ClusterAllocationExplainRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new ClusterAllocationExplainRequestBuilder(client, this);
-    }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/health/ClusterHealthAction.java

@@ -20,9 +20,8 @@
 package org.elasticsearch.action.admin.cluster.health;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public class ClusterHealthAction extends Action<ClusterHealthRequest, ClusterHealthResponse, ClusterHealthRequestBuilder> {
+public class ClusterHealthAction extends Action<ClusterHealthRequest, ClusterHealthResponse> {
 
     public static final ClusterHealthAction INSTANCE = new ClusterHealthAction();
     public static final String NAME = "cluster:monitor/health";
@@ -35,9 +34,4 @@ public class ClusterHealthAction extends Action<ClusterHealthRequest, ClusterHea
     public ClusterHealthResponse newResponse() {
         return new ClusterHealthResponse();
     }
-
-    @Override
-    public ClusterHealthRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new ClusterHealthRequestBuilder(client, this);
-    }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/node/hotthreads/NodesHotThreadsAction.java

@@ -20,9 +20,8 @@
 package org.elasticsearch.action.admin.cluster.node.hotthreads;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public class NodesHotThreadsAction extends Action<NodesHotThreadsRequest, NodesHotThreadsResponse, NodesHotThreadsRequestBuilder> {
+public class NodesHotThreadsAction extends Action<NodesHotThreadsRequest, NodesHotThreadsResponse> {
 
     public static final NodesHotThreadsAction INSTANCE = new NodesHotThreadsAction();
     public static final String NAME = "cluster:monitor/nodes/hot_threads";
@@ -35,9 +34,4 @@ public class NodesHotThreadsAction extends Action<NodesHotThreadsRequest, NodesH
     public NodesHotThreadsResponse newResponse() {
         return new NodesHotThreadsResponse();
     }
-
-    @Override
-    public NodesHotThreadsRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new NodesHotThreadsRequestBuilder(client, this);
-    }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/node/info/NodesInfoAction.java

@@ -20,9 +20,8 @@
 package org.elasticsearch.action.admin.cluster.node.info;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public class NodesInfoAction extends Action<NodesInfoRequest, NodesInfoResponse, NodesInfoRequestBuilder> {
+public class NodesInfoAction extends Action<NodesInfoRequest, NodesInfoResponse> {
 
     public static final NodesInfoAction INSTANCE = new NodesInfoAction();
     public static final String NAME = "cluster:monitor/nodes/info";
@@ -35,9 +34,4 @@ public class NodesInfoAction extends Action<NodesInfoRequest, NodesInfoResponse,
     public NodesInfoResponse newResponse() {
         return new NodesInfoResponse();
     }
-
-    @Override
-    public NodesInfoRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new NodesInfoRequestBuilder(client, this);
-    }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/node/stats/NodesStatsAction.java

@@ -20,9 +20,8 @@
 package org.elasticsearch.action.admin.cluster.node.stats;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public class NodesStatsAction extends Action<NodesStatsRequest, NodesStatsResponse, NodesStatsRequestBuilder> {
+public class NodesStatsAction extends Action<NodesStatsRequest, NodesStatsResponse> {
 
     public static final NodesStatsAction INSTANCE = new NodesStatsAction();
     public static final String NAME = "cluster:monitor/nodes/stats";
@@ -35,9 +34,4 @@ public class NodesStatsAction extends Action<NodesStatsRequest, NodesStatsRespon
     public NodesStatsResponse newResponse() {
         return new NodesStatsResponse();
     }
-
-    @Override
-    public NodesStatsRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new NodesStatsRequestBuilder(client, this);
-    }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/node/tasks/cancel/CancelTasksAction.java

@@ -20,12 +20,11 @@
 package org.elasticsearch.action.admin.cluster.node.tasks.cancel;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
 /**
  * Action for cancelling running tasks
  */
-public class CancelTasksAction extends Action<CancelTasksRequest, CancelTasksResponse, CancelTasksRequestBuilder> {
+public class CancelTasksAction extends Action<CancelTasksRequest, CancelTasksResponse> {
 
     public static final CancelTasksAction INSTANCE = new CancelTasksAction();
     public static final String NAME = "cluster:admin/tasks/cancel";
@@ -38,9 +37,4 @@ public class CancelTasksAction extends Action<CancelTasksRequest, CancelTasksRes
     public CancelTasksResponse newResponse() {
         return new CancelTasksResponse();
     }
-
-    @Override
-    public CancelTasksRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new CancelTasksRequestBuilder(client, this);
-    }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/node/tasks/get/GetTaskAction.java

@@ -20,12 +20,11 @@
 package org.elasticsearch.action.admin.cluster.node.tasks.get;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
 /**
  * Action for retrieving a list of currently running tasks
  */
-public class GetTaskAction extends Action<GetTaskRequest, GetTaskResponse, GetTaskRequestBuilder> {
+public class GetTaskAction extends Action<GetTaskRequest, GetTaskResponse> {
 
     public static final GetTaskAction INSTANCE = new GetTaskAction();
     public static final String NAME = "cluster:monitor/task/get";
@@ -38,9 +37,4 @@ public class GetTaskAction extends Action<GetTaskRequest, GetTaskResponse, GetTa
     public GetTaskResponse newResponse() {
         return new GetTaskResponse();
     }
-
-    @Override
-    public GetTaskRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new GetTaskRequestBuilder(client, this);
-    }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/node/tasks/get/GetTaskRequestBuilder.java

@@ -27,7 +27,7 @@ import org.elasticsearch.tasks.TaskId;
 /**
  * Builder for the request to retrieve the list of tasks running on the specified nodes
  */
-public class GetTaskRequestBuilder extends ActionRequestBuilder<GetTaskRequest, GetTaskResponse, GetTaskRequestBuilder> {
+public class GetTaskRequestBuilder extends ActionRequestBuilder<GetTaskRequest, GetTaskResponse> {
     public GetTaskRequestBuilder(ElasticsearchClient client, GetTaskAction action) {
         super(client, action, new GetTaskRequest());
     }

server/src/main/java/org/elasticsearch/action/admin/cluster/node/tasks/list/ListTasksAction.java

@@ -20,12 +20,11 @@
 package org.elasticsearch.action.admin.cluster.node.tasks.list;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
 /**
  * Action for retrieving a list of currently running tasks
  */
-public class ListTasksAction extends Action<ListTasksRequest, ListTasksResponse, ListTasksRequestBuilder> {
+public class ListTasksAction extends Action<ListTasksRequest, ListTasksResponse> {
 
     public static final ListTasksAction INSTANCE = new ListTasksAction();
     public static final String NAME = "cluster:monitor/tasks/lists";
@@ -38,9 +37,4 @@ public class ListTasksAction extends Action<ListTasksRequest, ListTasksResponse,
     public ListTasksResponse newResponse() {
         return new ListTasksResponse();
     }
-
-    @Override
-    public ListTasksRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new ListTasksRequestBuilder(client, this);
-    }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/node/tasks/list/ListTasksResponse.java

@@ -266,6 +266,6 @@ public class ListTasksResponse extends BaseTasksResponse implements ToXContentOb
 
     @Override
     public String toString() {
-        return Strings.toString(this);
+        return Strings.toString(this, true, true);
     }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/node/usage/NodesUsageAction.java

@@ -20,9 +20,8 @@
 package org.elasticsearch.action.admin.cluster.node.usage;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public class NodesUsageAction extends Action<NodesUsageRequest, NodesUsageResponse, NodesUsageRequestBuilder> {
+public class NodesUsageAction extends Action<NodesUsageRequest, NodesUsageResponse> {
 
     public static final NodesUsageAction INSTANCE = new NodesUsageAction();
     public static final String NAME = "cluster:monitor/nodes/usage";
@@ -31,11 +30,6 @@ public class NodesUsageAction extends Action<NodesUsageRequest, NodesUsageRespon
         super(NAME);
     }
 
-    @Override
-    public NodesUsageRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new NodesUsageRequestBuilder(client, this);
-    }
-
     @Override
     public NodesUsageResponse newResponse() {
         return new NodesUsageResponse();

server/src/main/java/org/elasticsearch/action/admin/cluster/node/usage/NodesUsageRequestBuilder.java

@@ -26,8 +26,7 @@ import org.elasticsearch.client.ElasticsearchClient;
 public class NodesUsageRequestBuilder
         extends NodesOperationRequestBuilder<NodesUsageRequest, NodesUsageResponse, NodesUsageRequestBuilder> {
 
-    public NodesUsageRequestBuilder(ElasticsearchClient client,
+    public NodesUsageRequestBuilder(ElasticsearchClient client, Action<NodesUsageRequest, NodesUsageResponse> action) {
-            Action<NodesUsageRequest, NodesUsageResponse, NodesUsageRequestBuilder> action) {
         super(client, action, new NodesUsageRequest());
     }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/remote/RemoteInfoAction.java

@@ -20,9 +20,8 @@
 package org.elasticsearch.action.admin.cluster.remote;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public final class RemoteInfoAction extends Action<RemoteInfoRequest, RemoteInfoResponse, RemoteInfoRequestBuilder> {
+public final class RemoteInfoAction extends Action<RemoteInfoRequest, RemoteInfoResponse> {
 
     public static final String NAME = "cluster:monitor/remote/info";
     public static final RemoteInfoAction INSTANCE = new RemoteInfoAction();
@@ -31,11 +30,6 @@ public final class RemoteInfoAction extends Action<RemoteInfoRequest, RemoteInfo
         super(NAME);
     }
 
-    @Override
-    public RemoteInfoRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new RemoteInfoRequestBuilder(client, INSTANCE);
-    }
-
     @Override
     public RemoteInfoResponse newResponse() {
         return new RemoteInfoResponse();

server/src/main/java/org/elasticsearch/action/admin/cluster/remote/RemoteInfoRequestBuilder.java

@@ -22,7 +22,7 @@ package org.elasticsearch.action.admin.cluster.remote;
 import org.elasticsearch.action.ActionRequestBuilder;
 import org.elasticsearch.client.ElasticsearchClient;
 
-public final class RemoteInfoRequestBuilder extends ActionRequestBuilder<RemoteInfoRequest, RemoteInfoResponse, RemoteInfoRequestBuilder> {
+public final class RemoteInfoRequestBuilder extends ActionRequestBuilder<RemoteInfoRequest, RemoteInfoResponse> {
 
     public RemoteInfoRequestBuilder(ElasticsearchClient client, RemoteInfoAction action) {
         super(client, action, new RemoteInfoRequest());

server/src/main/java/org/elasticsearch/action/admin/cluster/repositories/delete/DeleteRepositoryAction.java

@@ -20,12 +20,11 @@
 package org.elasticsearch.action.admin.cluster.repositories.delete;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
 /**
  * Unregister repository action
  */
-public class DeleteRepositoryAction extends Action<DeleteRepositoryRequest, DeleteRepositoryResponse, DeleteRepositoryRequestBuilder> {
+public class DeleteRepositoryAction extends Action<DeleteRepositoryRequest, DeleteRepositoryResponse> {
 
     public static final DeleteRepositoryAction INSTANCE = new DeleteRepositoryAction();
     public static final String NAME = "cluster:admin/repository/delete";
@@ -38,10 +37,5 @@ public class DeleteRepositoryAction extends Action<DeleteRepositoryRequest, Dele
     public DeleteRepositoryResponse newResponse() {
         return new DeleteRepositoryResponse();
     }
-
-    @Override
-    public DeleteRepositoryRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new DeleteRepositoryRequestBuilder(client, this);
-    }
 }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/repositories/get/GetRepositoriesAction.java

@@ -20,12 +20,11 @@
 package org.elasticsearch.action.admin.cluster.repositories.get;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
 /**
  * Get repositories action
  */
-public class GetRepositoriesAction extends Action<GetRepositoriesRequest, GetRepositoriesResponse, GetRepositoriesRequestBuilder> {
+public class GetRepositoriesAction extends Action<GetRepositoriesRequest, GetRepositoriesResponse> {
 
     public static final GetRepositoriesAction INSTANCE = new GetRepositoriesAction();
     public static final String NAME = "cluster:admin/repository/get";
@@ -38,10 +37,5 @@ public class GetRepositoriesAction extends Action<GetRepositoriesRequest, GetRep
     public GetRepositoriesResponse newResponse() {
         return new GetRepositoriesResponse();
     }
-
-    @Override
-    public GetRepositoriesRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new GetRepositoriesRequestBuilder(client, this);
-    }
 }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/repositories/put/PutRepositoryAction.java

@@ -20,12 +20,11 @@
 package org.elasticsearch.action.admin.cluster.repositories.put;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
 /**
  * Register repository action
  */
-public class PutRepositoryAction extends Action<PutRepositoryRequest, PutRepositoryResponse, PutRepositoryRequestBuilder> {
+public class PutRepositoryAction extends Action<PutRepositoryRequest, PutRepositoryResponse> {
 
     public static final PutRepositoryAction INSTANCE = new PutRepositoryAction();
     public static final String NAME = "cluster:admin/repository/put";
@@ -38,10 +37,5 @@ public class PutRepositoryAction extends Action<PutRepositoryRequest, PutReposit
     public PutRepositoryResponse newResponse() {
         return new PutRepositoryResponse();
     }
-
-    @Override
-    public PutRepositoryRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new PutRepositoryRequestBuilder(client, this);
-    }
 }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/repositories/verify/TransportVerifyRepositoryAction.java

@@ -73,7 +73,7 @@ public class TransportVerifyRepositoryAction extends TransportMasterNodeAction<V
                 if (verifyResponse.failed()) {
                     listener.onFailure(new RepositoryVerificationException(request.name(), verifyResponse.failureDescription()));
                 } else {
-                    listener.onResponse(new VerifyRepositoryResponse(clusterService.getClusterName(), verifyResponse.nodes()));
+                    listener.onResponse(new VerifyRepositoryResponse(verifyResponse.nodes()));
                 }
             }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/repositories/verify/VerifyRepositoryAction.java

@@ -20,12 +20,11 @@
 package org.elasticsearch.action.admin.cluster.repositories.verify;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
 /**
  * Unregister repository action
  */
-public class VerifyRepositoryAction extends Action<VerifyRepositoryRequest, VerifyRepositoryResponse, VerifyRepositoryRequestBuilder> {
+public class VerifyRepositoryAction extends Action<VerifyRepositoryRequest, VerifyRepositoryResponse> {
 
     public static final VerifyRepositoryAction INSTANCE = new VerifyRepositoryAction();
     public static final String NAME = "cluster:admin/repository/verify";
@@ -38,10 +37,5 @@ public class VerifyRepositoryAction extends Action<VerifyRepositoryRequest, Veri
     public VerifyRepositoryResponse newResponse() {
         return new VerifyRepositoryResponse();
     }
-
-    @Override
-    public VerifyRepositoryRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new VerifyRepositoryRequestBuilder(client, this);
-    }
 }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/repositories/verify/VerifyRepositoryResponse.java

@@ -19,16 +19,13 @@
 
 package org.elasticsearch.action.admin.cluster.repositories.verify;
 
-import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionResponse;
-import org.elasticsearch.cluster.ClusterName;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.common.ParseField;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.io.stream.Writeable;
-import org.elasticsearch.common.transport.TransportAddress;
 import org.elasticsearch.common.xcontent.ObjectParser;
 import org.elasticsearch.common.xcontent.ToXContentObject;
 import org.elasticsearch.common.xcontent.XContentBuilder;
@@ -36,7 +33,6 @@ import org.elasticsearch.common.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
 import java.util.stream.Collectors;
@@ -92,20 +88,6 @@ public class VerifyRepositoryResponse extends ActionResponse implements ToXConte
             return builder;
         }
 
-        /**
-         * Temporary method that allows turning a {@link NodeView} into a {@link DiscoveryNode}. This representation will never be used in
-         * practice, because in >= 6.4 a consumer of the response will only be able to retrieve a representation of {@link NodeView}
-         * objects.
-         *
-         * Effectively this will be used to hold the state of the object in 6.x so there is no need to have 2 backing objects that
-         * represent the state of the Response. In practice these will always be read by a consumer as a NodeView, but it eases the
-         * transition to master which will not contain any representation of a {@link DiscoveryNode}.
-         */
-        DiscoveryNode convertToDiscoveryNode() {
-            return new DiscoveryNode(name, nodeId, "", "", "", new TransportAddress(TransportAddress.META_ADDRESS, 0),
-                Collections.emptyMap(), Collections.emptySet(), Version.CURRENT);
-        }
-
         @Override
         public boolean equals(Object obj) {
             if (obj == null) {
@@ -125,10 +107,7 @@ public class VerifyRepositoryResponse extends ActionResponse implements ToXConte
         }
     }
 
-    private List<DiscoveryNode> nodes;
+    private List<NodeView> nodes;
-
-    private ClusterName clusterName;
-
 
     private static final ObjectParser<VerifyRepositoryResponse, Void> PARSER =
         new ObjectParser<>(VerifyRepositoryResponse.class.getName(), VerifyRepositoryResponse::new);
@@ -139,43 +118,28 @@ public class VerifyRepositoryResponse extends ActionResponse implements ToXConte
     VerifyRepositoryResponse() {
     }
 
-    public VerifyRepositoryResponse(ClusterName clusterName, DiscoveryNode[] nodes) {
+    public VerifyRepositoryResponse(DiscoveryNode[] nodes) {
-        this.clusterName = clusterName;
+        this.nodes = Arrays.stream(nodes).map(dn ->  new NodeView(dn.getId(), dn.getName())).collect(Collectors.toList());
-        this.nodes = Arrays.asList(nodes);
     }
 
     @Override
     public void readFrom(StreamInput in) throws IOException {
         super.readFrom(in);
-        if (in.getVersion().onOrAfter(Version.V_6_4_0)) {
+        this.nodes = in.readList(NodeView::new);
-            this.nodes = in.readList(NodeView::new).stream().map(n -> n.convertToDiscoveryNode()).collect(Collectors.toList());
-        } else {
-            clusterName = new ClusterName(in);
-            this.nodes = in.readList(DiscoveryNode::new);
-        }
     }
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
-        if (out.getVersion().onOrAfter(Version.V_6_4_0)) {
-            out.writeList(getNodes());
-        } else {
-            clusterName.writeTo(out);
         out.writeList(nodes);
     }
-    }
 
     public List<NodeView> getNodes() {
-        return nodes.stream().map(dn -> new NodeView(dn.getId(), dn.getName())).collect(Collectors.toList());
+        return nodes;
-    }
-
-    public ClusterName getClusterName() {
-        return clusterName;
     }
 
     protected void setNodes(List<NodeView> nodes) {
-        this.nodes = nodes.stream().map(n -> n.convertToDiscoveryNode()).collect(Collectors.toList());
+        this.nodes = nodes;
     }
 
     @Override
@@ -184,12 +148,8 @@ public class VerifyRepositoryResponse extends ActionResponse implements ToXConte
         {
             builder.startObject(NODES);
             {
-                for (DiscoveryNode node : nodes) {
+                for (NodeView node : nodes) {
-                    builder.startObject(node.getId());
+                    node.toXContent(builder, params);
-                    {
-                        builder.field(NAME, node.getName());
-                    }
-                    builder.endObject();
                 }
             }
             builder.endObject();

server/src/main/java/org/elasticsearch/action/admin/cluster/reroute/ClusterRerouteAction.java

@@ -20,9 +20,8 @@
 package org.elasticsearch.action.admin.cluster.reroute;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public class ClusterRerouteAction extends Action<ClusterRerouteRequest, ClusterRerouteResponse, ClusterRerouteRequestBuilder> {
+public class ClusterRerouteAction extends Action<ClusterRerouteRequest, ClusterRerouteResponse> {
 
     public static final ClusterRerouteAction INSTANCE = new ClusterRerouteAction();
     public static final String NAME = "cluster:admin/reroute";
@@ -35,9 +34,4 @@ public class ClusterRerouteAction extends Action<ClusterRerouteRequest, ClusterR
     public ClusterRerouteResponse newResponse() {
         return new ClusterRerouteResponse();
     }
-
-    @Override
-    public ClusterRerouteRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new ClusterRerouteRequestBuilder(client, this);
-    }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/reroute/ClusterRerouteResponse.java

@@ -19,7 +19,9 @@
 
 package org.elasticsearch.action.admin.cluster.reroute;
 
+import org.elasticsearch.Version;
 import org.elasticsearch.action.support.master.AcknowledgedResponse;
+import org.elasticsearch.cluster.ClusterModule;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.routing.allocation.RoutingExplanations;
 import org.elasticsearch.common.io.stream.StreamInput;
@@ -70,7 +72,11 @@ public class ClusterRerouteResponse extends AcknowledgedResponse implements ToXC
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
+        if (out.getVersion().onOrAfter(Version.V_6_3_0)) {
             state.writeTo(out);
+        } else {
+            ClusterModule.filterCustomsForPre63Clients(state).writeTo(out);
+        }
         writeAcknowledged(out);
         RoutingExplanations.writeTo(explanations, out);
     }

server/src/main/java/org/elasticsearch/action/admin/cluster/settings/ClusterUpdateSettingsAction.java

@@ -20,9 +20,8 @@
 package org.elasticsearch.action.admin.cluster.settings;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public class ClusterUpdateSettingsAction extends Action<ClusterUpdateSettingsRequest, ClusterUpdateSettingsResponse, ClusterUpdateSettingsRequestBuilder> {
+public class ClusterUpdateSettingsAction extends Action<ClusterUpdateSettingsRequest, ClusterUpdateSettingsResponse> {
 
     public static final ClusterUpdateSettingsAction INSTANCE = new ClusterUpdateSettingsAction();
     public static final String NAME = "cluster:admin/settings/update";
@@ -35,9 +34,4 @@ public class ClusterUpdateSettingsAction extends Action<ClusterUpdateSettingsReq
     public ClusterUpdateSettingsResponse newResponse() {
         return new ClusterUpdateSettingsResponse();
     }
-
-    @Override
-    public ClusterUpdateSettingsRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new ClusterUpdateSettingsRequestBuilder(client, this);
-    }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/shards/ClusterSearchShardsAction.java

@@ -20,9 +20,8 @@
 package org.elasticsearch.action.admin.cluster.shards;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public class ClusterSearchShardsAction extends Action<ClusterSearchShardsRequest, ClusterSearchShardsResponse, ClusterSearchShardsRequestBuilder> {
+public class ClusterSearchShardsAction extends Action<ClusterSearchShardsRequest, ClusterSearchShardsResponse> {
 
     public static final ClusterSearchShardsAction INSTANCE = new ClusterSearchShardsAction();
     public static final String NAME = "indices:admin/shards/search_shards";
@@ -35,9 +34,4 @@ public class ClusterSearchShardsAction extends Action<ClusterSearchShardsRequest
     public ClusterSearchShardsResponse newResponse() {
         return new ClusterSearchShardsResponse();
     }
-
-    @Override
-    public ClusterSearchShardsRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new ClusterSearchShardsRequestBuilder(client, this);
-    }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/create/CreateSnapshotAction.java

@@ -20,12 +20,11 @@
 package org.elasticsearch.action.admin.cluster.snapshots.create;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
 /**
  * Create snapshot action
  */
-public class CreateSnapshotAction extends Action<CreateSnapshotRequest, CreateSnapshotResponse, CreateSnapshotRequestBuilder> {
+public class CreateSnapshotAction extends Action<CreateSnapshotRequest, CreateSnapshotResponse> {
 
     public static final CreateSnapshotAction INSTANCE = new CreateSnapshotAction();
     public static final String NAME = "cluster:admin/snapshot/create";
@@ -38,10 +37,5 @@ public class CreateSnapshotAction extends Action<CreateSnapshotRequest, CreateSn
     public CreateSnapshotResponse newResponse() {
         return new CreateSnapshotResponse();
     }
-
-    @Override
-    public CreateSnapshotRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new CreateSnapshotRequestBuilder(client, this);
-    }
 }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/delete/DeleteSnapshotAction.java

@@ -20,12 +20,11 @@
 package org.elasticsearch.action.admin.cluster.snapshots.delete;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
 /**
  * Delete snapshot action
  */
-public class DeleteSnapshotAction extends Action<DeleteSnapshotRequest, DeleteSnapshotResponse, DeleteSnapshotRequestBuilder> {
+public class DeleteSnapshotAction extends Action<DeleteSnapshotRequest, DeleteSnapshotResponse> {
 
     public static final DeleteSnapshotAction INSTANCE = new DeleteSnapshotAction();
     public static final String NAME = "cluster:admin/snapshot/delete";
@@ -38,10 +37,5 @@ public class DeleteSnapshotAction extends Action<DeleteSnapshotRequest, DeleteSn
     public DeleteSnapshotResponse newResponse() {
         return new DeleteSnapshotResponse();
     }
-
-    @Override
-    public DeleteSnapshotRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new DeleteSnapshotRequestBuilder(client, this);
-    }
 }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/get/GetSnapshotsAction.java

@@ -20,12 +20,11 @@
 package org.elasticsearch.action.admin.cluster.snapshots.get;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
 /**
  * Get snapshots action
  */
-public class GetSnapshotsAction extends Action<GetSnapshotsRequest, GetSnapshotsResponse, GetSnapshotsRequestBuilder> {
+public class GetSnapshotsAction extends Action<GetSnapshotsRequest, GetSnapshotsResponse> {
 
     public static final GetSnapshotsAction INSTANCE = new GetSnapshotsAction();
     public static final String NAME = "cluster:admin/snapshot/get";
@@ -38,10 +37,5 @@ public class GetSnapshotsAction extends Action<GetSnapshotsRequest, GetSnapshots
     public GetSnapshotsResponse newResponse() {
         return new GetSnapshotsResponse();
     }
-
-    @Override
-    public GetSnapshotsRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new GetSnapshotsRequestBuilder(client, this);
-    }
 }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/restore/RestoreSnapshotAction.java

@@ -20,12 +20,11 @@
 package org.elasticsearch.action.admin.cluster.snapshots.restore;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
 /**
  * Restore snapshot action
  */
-public class RestoreSnapshotAction extends Action<RestoreSnapshotRequest, RestoreSnapshotResponse, RestoreSnapshotRequestBuilder> {
+public class RestoreSnapshotAction extends Action<RestoreSnapshotRequest, RestoreSnapshotResponse> {
 
     public static final RestoreSnapshotAction INSTANCE = new RestoreSnapshotAction();
     public static final String NAME = "cluster:admin/snapshot/restore";
@@ -38,10 +37,5 @@ public class RestoreSnapshotAction extends Action<RestoreSnapshotRequest, Restor
     public RestoreSnapshotResponse newResponse() {
         return new RestoreSnapshotResponse();
     }
-
-    @Override
-    public RestoreSnapshotRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new RestoreSnapshotRequestBuilder(client, this);
-    }
 }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/status/SnapshotsStatusAction.java

@@ -20,12 +20,11 @@
 package org.elasticsearch.action.admin.cluster.snapshots.status;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
 /**
  * Snapshots status action
  */
-public class SnapshotsStatusAction extends Action<SnapshotsStatusRequest, SnapshotsStatusResponse, SnapshotsStatusRequestBuilder> {
+public class SnapshotsStatusAction extends Action<SnapshotsStatusRequest, SnapshotsStatusResponse> {
 
     public static final SnapshotsStatusAction INSTANCE = new SnapshotsStatusAction();
     public static final String NAME = "cluster:admin/snapshot/status";
@@ -38,10 +37,5 @@ public class SnapshotsStatusAction extends Action<SnapshotsStatusRequest, Snapsh
     public SnapshotsStatusResponse newResponse() {
         return new SnapshotsStatusResponse();
     }
-
-    @Override
-    public SnapshotsStatusRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new SnapshotsStatusRequestBuilder(client, this);
-    }
 }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/state/ClusterStateAction.java

@@ -20,9 +20,8 @@
 package org.elasticsearch.action.admin.cluster.state;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public class ClusterStateAction extends Action<ClusterStateRequest, ClusterStateResponse, ClusterStateRequestBuilder> {
+public class ClusterStateAction extends Action<ClusterStateRequest, ClusterStateResponse> {
 
     public static final ClusterStateAction INSTANCE = new ClusterStateAction();
     public static final String NAME = "cluster:monitor/state";
@@ -35,9 +34,4 @@ public class ClusterStateAction extends Action<ClusterStateRequest, ClusterState
     public ClusterStateResponse newResponse() {
         return new ClusterStateResponse();
     }
-
-    @Override
-    public ClusterStateRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new ClusterStateRequestBuilder(client, this);
-    }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/state/ClusterStateResponse.java

@@ -21,6 +21,7 @@ package org.elasticsearch.action.admin.cluster.state;
 
 import org.elasticsearch.Version;
 import org.elasticsearch.action.ActionResponse;
+import org.elasticsearch.cluster.ClusterModule;
 import org.elasticsearch.cluster.ClusterName;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.common.io.stream.StreamInput;
@@ -94,7 +95,11 @@ public class ClusterStateResponse extends ActionResponse {
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
         clusterName.writeTo(out);
+        if (out.getVersion().onOrAfter(Version.V_6_3_0)) {
             clusterState.writeTo(out);
+        } else {
+            ClusterModule.filterCustomsForPre63Clients(clusterState).writeTo(out);
+        }
         if (out.getVersion().onOrAfter(Version.V_6_0_0_alpha1)) {
             totalCompressedSize.writeTo(out);
         }

server/src/main/java/org/elasticsearch/action/admin/cluster/stats/ClusterStatsAction.java

@@ -20,9 +20,8 @@
 package org.elasticsearch.action.admin.cluster.stats;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public class ClusterStatsAction extends Action<ClusterStatsRequest, ClusterStatsResponse, ClusterStatsRequestBuilder> {
+public class ClusterStatsAction extends Action<ClusterStatsRequest, ClusterStatsResponse> {
 
     public static final ClusterStatsAction INSTANCE = new ClusterStatsAction();
     public static final String NAME = "cluster:monitor/stats";
@@ -35,9 +34,4 @@ public class ClusterStatsAction extends Action<ClusterStatsRequest, ClusterStats
     public ClusterStatsResponse newResponse() {
         return new ClusterStatsResponse();
     }
-
-    @Override
-    public ClusterStatsRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new ClusterStatsRequestBuilder(client, this);
-    }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/storedscripts/DeleteStoredScriptAction.java

@@ -20,10 +20,8 @@
 package org.elasticsearch.action.admin.cluster.storedscripts;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public class DeleteStoredScriptAction extends Action<DeleteStoredScriptRequest, DeleteStoredScriptResponse,
+public class DeleteStoredScriptAction extends Action<DeleteStoredScriptRequest, DeleteStoredScriptResponse> {
-        DeleteStoredScriptRequestBuilder> {
 
     public static final DeleteStoredScriptAction INSTANCE = new DeleteStoredScriptAction();
     public static final String NAME = "cluster:admin/script/delete";
@@ -36,9 +34,4 @@ public class DeleteStoredScriptAction extends Action<DeleteStoredScriptRequest,
     public DeleteStoredScriptResponse newResponse() {
         return new DeleteStoredScriptResponse();
     }
-
-    @Override
-    public DeleteStoredScriptRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new DeleteStoredScriptRequestBuilder(client, this);
-    }
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/storedscripts/GetStoredScriptAction.java

@@ -20,10 +20,8 @@
 package org.elasticsearch.action.admin.cluster.storedscripts;
 
 import org.elasticsearch.action.Action;
-import org.elasticsearch.client.ElasticsearchClient;
 
-public class GetStoredScriptAction extends Action<GetStoredScriptRequest, GetStoredScriptResponse,
+public class GetStoredScriptAction extends Action<GetStoredScriptRequest, GetStoredScriptResponse> {
-        GetStoredScriptRequestBuilder> {
 
     public static final GetStoredScriptAction INSTANCE = new GetStoredScriptAction();
     public static final String NAME = "cluster:admin/script/get";
@@ -36,10 +34,4 @@ public class GetStoredScriptAction extends Action<GetStoredScriptRequest, GetSto
     public GetStoredScriptResponse newResponse() {
         return new GetStoredScriptResponse();
     }
-
-    @Override
-    public GetStoredScriptRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new GetStoredScriptRequestBuilder(client, this);
-    }
-
 }

server/src/main/java/org/elasticsearch/action/admin/cluster/storedscripts/PutStoredScriptAction.java

@@ -23,8 +23,7 @@ import org.elasticsearch.action.Action;
 import org.elasticsearch.client.ElasticsearchClient;
 
 
-public class PutStoredScriptAction extends Action<PutStoredScriptRequest, PutStoredScriptResponse,
+public class PutStoredScriptAction extends Action<PutStoredScriptRequest, PutStoredScriptResponse> {
-        PutStoredScriptRequestBuilder> {
 
     public static final PutStoredScriptAction INSTANCE = new PutStoredScriptAction();
     public static final String NAME = "cluster:admin/script/put";
@@ -39,9 +38,4 @@ public class PutStoredScriptAction extends Action<PutStoredScriptRequest, PutSto
     public PutStoredScriptResponse newResponse() {
         return new PutStoredScriptResponse();
     }
-
-    @Override
-    public PutStoredScriptRequestBuilder newRequestBuilder(ElasticsearchClient client) {
-        return new PutStoredScriptRequestBuilder(client, this);
-    }
 }