HLRC: Fix Reindex from remote query logic (#36908)

The query object was incorrectly added to the remote object in the
xcontent. This fix moves the query back into the source, if it was
passed in as part of the RemoteInfo. It also adds a IPv6 test for
reindex from remote such that we can properly validate this.

client/rest-high-level/build.gradle

@@ -103,6 +103,7 @@ integTestRunner {
 
 integTestCluster {
   systemProperty 'es.scripting.update.ctx_in_params', 'false'
+  setting 'reindex.remote.whitelist', '"[::1]:*"'
   setting 'xpack.license.self_generated.type', 'trial'
   setting 'xpack.security.enabled', 'true'
   setting 'xpack.security.authc.token.enabled', 'true'

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

@@ -19,6 +19,7 @@
 
 package org.elasticsearch.client.documentation;
 
+import org.apache.http.HttpHost;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.action.DocWriteRequest;
@@ -823,9 +824,6 @@ public class CRUDDocumentationIT extends ESRestHighLevelClientTestCase {
             // tag::reindex-request-conflicts
             request.setConflicts("proceed"); // <1>
             // end::reindex-request-conflicts
-            // tag::reindex-request-query
-            request.setSourceQuery(new TermQueryBuilder("user", "kimchy")); // <1>
-            // end::reindex-request-query
             // tag::reindex-request-size
             request.setSize(10); // <1>
             // end::reindex-request-size
@@ -846,27 +844,29 @@ public class CRUDDocumentationIT extends ESRestHighLevelClientTestCase {
                     "if (ctx._source.user == 'kimchy') {ctx._source.likes++;}",
                     Collections.emptyMap())); // <1>
             // end::reindex-request-script
+            HttpHost host = getClusterHosts().get(0);
+            Integer remotePort = host.getPort();
+            String remoteHost = host.getHostName();
+            String user = "test_user";
+            String password = "test-password";
+
             // tag::reindex-request-remote
             request.setRemoteInfo(
                 new RemoteInfo(
-                    "https", "localhost", 9002, null,
+                    "http", remoteHost, remotePort, null,
                     new BytesArray(new MatchAllQueryBuilder().toString()),
-                    "user", "pass", Collections.emptyMap(),
+                    user, password, Collections.emptyMap(),
                     new TimeValue(100, TimeUnit.MILLISECONDS),
                     new TimeValue(100, TimeUnit.SECONDS)
                 )
             ); // <1>
             // end::reindex-request-remote
-            request.setRemoteInfo(null); // Remove it for tests
             // tag::reindex-request-timeout
             request.setTimeout(TimeValue.timeValueMinutes(2)); // <1>
             // end::reindex-request-timeout
             // tag::reindex-request-refresh
             request.setRefresh(true); // <1>
             // end::reindex-request-refresh
-            // tag::reindex-request-slices
-            request.setSlices(2); // <1>
-            // end::reindex-request-slices
             // tag::reindex-request-scroll
             request.setScroll(TimeValue.timeValueMinutes(10)); // <1>
             // end::reindex-request-scroll
@@ -904,6 +904,14 @@ public class CRUDDocumentationIT extends ESRestHighLevelClientTestCase {
             request.setSourceIndices("source1");
             request.setDestIndex("dest");
 
+            // These cannot be set with a remote set, so its set here instead for the docs
+            // tag::reindex-request-query
+            request.setSourceQuery(new TermQueryBuilder("user", "kimchy")); // <1>
+            // end::reindex-request-query
+            // tag::reindex-request-slices
+            request.setSlices(2); // <1>
+            // end::reindex-request-slices
+
             ActionListener<BulkByScrollResponse> listener;
             // tag::reindex-execute-listener
             listener = new ActionListener<BulkByScrollResponse>() {

server/src/main/java/org/elasticsearch/index/reindex/ReindexRequest.java

@@ -293,6 +293,7 @@ public class ReindexRequest extends AbstractBulkIndexByScrollRequest<ReindexRequ
             builder.startObject("source");
             if (remoteInfo != null) {
                 builder.field("remote", remoteInfo);
+                builder.rawField("query", remoteInfo.getQuery().streamInput(), builder.contentType());
             }
             builder.array("index", getSearchRequest().indices());
             String[] types = getSearchRequest().types();

server/src/main/java/org/elasticsearch/index/reindex/RemoteInfo.java

@@ -209,7 +209,6 @@ public class RemoteInfo implements Writeable, ToXContentObject {
         }
         builder.field("socket_timeout", socketTimeout.getStringRep());
         builder.field("connect_timeout", connectTimeout.getStringRep());
-        builder.field("query", query);
         builder.endObject();
         return builder;
     }