Return 200 on GET requests for all resources when none exists (elastic/elasticsearch#694)

When a user makes a GET request to retrieve all resources of a type
(e.g. anomaly_detectors) and none exists, the response should be an
empty array with 200 status code. This commit fixes this issue for:

* anomaly_detectors and _stats
* schedulers and _stats
* lists
* buckets

All other GETs work fine already.

Original commit: elastic/x-pack-elasticsearch@4daaa91aa4

elasticsearch/src/main/java/org/elasticsearch/xpack/ml/action/GetBucketsAction.java

@@ -22,12 +22,11 @@ import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.ObjectParser;
-import org.elasticsearch.common.xcontent.StatusToXContentObject;
 import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.ToXContentObject;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentParser;
-import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
 import org.elasticsearch.xpack.ml.job.Job;
@@ -326,7 +325,7 @@ public class GetBucketsAction extends Action<GetBucketsAction.Request, GetBucket
         }
     }
 
-    public static class Response extends ActionResponse implements StatusToXContentObject {
+    public static class Response extends ActionResponse implements ToXContentObject {
 
         private QueryPage<Bucket> buckets;
 
@@ -361,11 +360,6 @@ public class GetBucketsAction extends Action<GetBucketsAction.Request, GetBucket
             return builder;
         }
 
-        @Override
-        public RestStatus status() {
-            return buckets.count() == 0 ? RestStatus.NOT_FOUND : RestStatus.OK;
-        }
-
         @Override
         public int hashCode() {
             return Objects.hash(buckets);

elasticsearch/src/main/java/org/elasticsearch/xpack/ml/action/GetJobsAction.java

@@ -23,10 +23,9 @@ import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.settings.Settings;
-import org.elasticsearch.common.xcontent.StatusToXContentObject;
+import org.elasticsearch.common.xcontent.ToXContentObject;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
-import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
 import org.elasticsearch.xpack.ml.job.Job;
@@ -112,7 +111,7 @@ public class GetJobsAction extends Action<GetJobsAction.Request, GetJobsAction.R
         }
     }
 
-    public static class Response extends ActionResponse implements StatusToXContentObject {
+    public static class Response extends ActionResponse implements ToXContentObject {
 
         private QueryPage<Job> jobs;
 
@@ -146,11 +145,6 @@ public class GetJobsAction extends Action<GetJobsAction.Request, GetJobsAction.R
             return builder;
         }
 
-        @Override
-        public RestStatus status() {
-            return jobs.count() == 0 ? RestStatus.NOT_FOUND : RestStatus.OK;
-        }
-
         @Override
         public int hashCode() {
             return Objects.hash(jobs);

elasticsearch/src/main/java/org/elasticsearch/xpack/ml/action/GetJobsStatsAction.java

@@ -23,11 +23,10 @@ import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.io.stream.Writeable;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.util.concurrent.AtomicArray;
-import org.elasticsearch.common.xcontent.StatusToXContentObject;
 import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.ToXContentObject;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
-import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
 import org.elasticsearch.xpack.ml.job.DataCounts;
@@ -42,6 +41,7 @@ import org.elasticsearch.xpack.ml.job.persistence.QueryPage;
 import org.elasticsearch.xpack.ml.utils.ExceptionsHelper;
 
 import java.io.IOException;
+import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
@@ -129,7 +129,7 @@ public class GetJobsStatsAction extends Action<GetJobsStatsAction.Request, GetJo
         }
     }
 
-    public static class Response extends ActionResponse implements StatusToXContentObject {
+    public static class Response extends ActionResponse implements ToXContentObject {
 
         public static class JobStats implements ToXContent, Writeable {
             private final String jobId;
@@ -235,11 +235,6 @@ public class GetJobsStatsAction extends Action<GetJobsStatsAction.Request, GetJo
             jobsStats.writeTo(out);
         }
 
-        @Override
-        public RestStatus status() {
-            return jobsStats.count() == 0 ? RestStatus.NOT_FOUND : RestStatus.OK;
-        }
-
         @Override
         public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
             builder.startObject();;
@@ -305,6 +300,9 @@ public class GetJobsStatsAction extends Action<GetJobsStatsAction.Request, GetJo
         protected void doExecute(Request request, ActionListener<Response> listener) {
             logger.debug("Get stats for job '{}'", request.getJobId());
             QueryPage<Job> jobs = jobManager.getJob(request.getJobId(), clusterService.state());
+            if (jobs.count() == 0) {
+                listener.onResponse(new GetJobsStatsAction.Response(new QueryPage<>(Collections.emptyList(), 0, Job.RESULTS_FIELD)));
+            }
             MlMetadata mlMetadata = clusterService.state().metaData().custom(MlMetadata.TYPE);
 
             AtomicInteger counter = new AtomicInteger(0);

elasticsearch/src/main/java/org/elasticsearch/xpack/ml/action/GetListAction.java

@@ -183,7 +183,7 @@ public class GetListAction extends Action<GetListAction.Request, GetListAction.R
 
         @Override
         public RestStatus status() {
-            return lists.count() == 0 ? RestStatus.NOT_FOUND : RestStatus.OK;
+            return RestStatus.OK;
         }
 
         @Override
@@ -319,24 +319,17 @@ public class GetListAction extends Action<GetListAction.Request, GetListAction.R
                 public void onResponse(SearchResponse response) {
 
                     try {
-                        QueryPage<ListDocument> responseBody;
-                        if (response.getHits().hits().length > 0) {
-                            List<ListDocument> docs = new ArrayList<>(response.getHits().hits().length);
-                            for (SearchHit hit : response.getHits().getHits()) {
-                                BytesReference docSource = hit.sourceRef();
-                                XContentParser parser =
-                                        XContentFactory.xContent(docSource).createParser(NamedXContentRegistry.EMPTY, docSource);
-                                docs.add(ListDocument.PARSER.apply(parser, () -> parseFieldMatcher));
-                            }
-
-                            responseBody = new QueryPage<>(docs, docs.size(), ListDocument.RESULTS_FIELD);
-
-                            Response listResponse = new Response(responseBody);
-                            listener.onResponse(listResponse);
-                        } else {
-                            this.onFailure(QueryPage.emptyQueryPage(ListDocument.RESULTS_FIELD));
+                        List<ListDocument> docs = new ArrayList<>();
+                        for (SearchHit hit : response.getHits().getHits()) {
+                            BytesReference docSource = hit.sourceRef();
+                            XContentParser parser =
+                                    XContentFactory.xContent(docSource).createParser(NamedXContentRegistry.EMPTY, docSource);
+                            docs.add(ListDocument.PARSER.apply(parser, () -> parseFieldMatcher));
                         }
 
+                        Response listResponse = new Response(new QueryPage<>(docs, docs.size(), ListDocument.RESULTS_FIELD));
+                        listener.onResponse(listResponse);
+
                     } catch (Exception e) {
                         this.onFailure(e);
                     }

elasticsearch/src/main/java/org/elasticsearch/xpack/ml/action/GetSchedulersAction.java

@@ -23,10 +23,9 @@ import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.settings.Settings;
-import org.elasticsearch.common.xcontent.StatusToXContentObject;
+import org.elasticsearch.common.xcontent.ToXContentObject;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
-import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
 import org.elasticsearch.xpack.ml.job.metadata.MlMetadata;
@@ -119,7 +118,7 @@ public class GetSchedulersAction extends Action<GetSchedulersAction.Request, Get
         }
     }
 
-    public static class Response extends ActionResponse implements StatusToXContentObject {
+    public static class Response extends ActionResponse implements ToXContentObject {
 
         private QueryPage<SchedulerConfig> schedulers;
 
@@ -145,11 +144,6 @@ public class GetSchedulersAction extends Action<GetSchedulersAction.Request, Get
             schedulers.writeTo(out);
         }
 
-        @Override
-        public RestStatus status() {
-            return schedulers.count() == 0 ? RestStatus.NOT_FOUND : RestStatus.OK;
-        }
-
         @Override
         public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
             builder.startObject();

elasticsearch/src/main/java/org/elasticsearch/xpack/ml/action/GetSchedulersStatsAction.java

@@ -24,11 +24,10 @@ 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.settings.Settings;
-import org.elasticsearch.common.xcontent.StatusToXContentObject;
 import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.ToXContentObject;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
-import org.elasticsearch.rest.RestStatus;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
 import org.elasticsearch.xpack.ml.job.metadata.MlMetadata;
@@ -123,7 +122,7 @@ public class GetSchedulersStatsAction extends Action<GetSchedulersStatsAction.Re
         }
     }
 
-    public static class Response extends ActionResponse implements StatusToXContentObject {
+    public static class Response extends ActionResponse implements ToXContentObject {
 
         public static class SchedulerStats implements ToXContent, Writeable {
 
@@ -206,11 +205,6 @@ public class GetSchedulersStatsAction extends Action<GetSchedulersStatsAction.Re
             schedulersStats.writeTo(out);
         }
 
-        @Override
-        public RestStatus status() {
-            return schedulersStats.count() == 0 ? RestStatus.NOT_FOUND : RestStatus.OK;
-        }
-
         @Override
         public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
             builder.startObject();

elasticsearch/src/main/java/org/elasticsearch/xpack/ml/job/manager/JobManager.java

@@ -101,7 +101,7 @@ public class JobManager extends AbstractComponent {
         Job job = mlMetadata.getJobs().get(jobId);
         if (job == null) {
             logger.debug(String.format(Locale.ROOT, "Cannot find job '%s'", jobId));
-            throw QueryPage.emptyQueryPage(Job.RESULTS_FIELD);
+            throw ExceptionsHelper.missingJobException(jobId);
         }
 
         logger.debug("Returning job [" + jobId + "]");

elasticsearch/src/main/java/org/elasticsearch/xpack/ml/rest/job/RestGetJobsAction.java

@@ -11,7 +11,7 @@ import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestController;
 import org.elasticsearch.rest.RestRequest;
-import org.elasticsearch.rest.action.RestStatusToXContentListener;
+import org.elasticsearch.rest.action.RestToXContentListener;
 import org.elasticsearch.xpack.ml.MlPlugin;
 import org.elasticsearch.xpack.ml.action.GetJobsAction;
 import org.elasticsearch.xpack.ml.job.Job;
@@ -34,6 +34,6 @@ public class RestGetJobsAction extends BaseRestHandler {
     @Override
     protected RestChannelConsumer prepareRequest(RestRequest restRequest, NodeClient client) throws IOException {
         GetJobsAction.Request request = new GetJobsAction.Request(restRequest.param(Job.ID.getPreferredName()));
-        return channel -> transportGetJobAction.execute(request, new RestStatusToXContentListener<>(channel));
+        return channel -> transportGetJobAction.execute(request, new RestToXContentListener<>(channel));
     }
 }

elasticsearch/src/main/java/org/elasticsearch/xpack/ml/rest/job/RestGetJobsStatsAction.java

@@ -11,7 +11,7 @@ import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestController;
 import org.elasticsearch.rest.RestRequest;
-import org.elasticsearch.rest.action.RestStatusToXContentListener;
+import org.elasticsearch.rest.action.RestToXContentListener;
 import org.elasticsearch.xpack.ml.MlPlugin;
 import org.elasticsearch.xpack.ml.action.GetJobsStatsAction;
 import org.elasticsearch.xpack.ml.job.Job;
@@ -35,6 +35,6 @@ public class RestGetJobsStatsAction extends BaseRestHandler {
     @Override
     protected RestChannelConsumer prepareRequest(RestRequest restRequest, NodeClient client) throws IOException {
         GetJobsStatsAction.Request request = new GetJobsStatsAction.Request(restRequest.param(Job.ID.getPreferredName()));
-        return channel -> transportGetJobsStatsAction.execute(request, new RestStatusToXContentListener<>(channel));
+        return channel -> transportGetJobsStatsAction.execute(request, new RestToXContentListener<>(channel));
     }
 }

elasticsearch/src/main/java/org/elasticsearch/xpack/ml/rest/results/RestGetBucketsAction.java

@@ -12,7 +12,7 @@ import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestController;
 import org.elasticsearch.rest.RestRequest;
-import org.elasticsearch.rest.action.RestStatusToXContentListener;
+import org.elasticsearch.rest.action.RestToXContentListener;
 import org.elasticsearch.xpack.ml.MlPlugin;
 import org.elasticsearch.xpack.ml.action.GetBucketsAction;
 import org.elasticsearch.xpack.ml.job.Job;
@@ -90,6 +90,6 @@ public class RestGetBucketsAction extends BaseRestHandler {
             request.setIncludeInterim(restRequest.paramAsBoolean(GetBucketsAction.Request.INCLUDE_INTERIM.getPreferredName(), false));
         }
 
-        return channel -> transportAction.execute(request, new RestStatusToXContentListener<>(channel));
+        return channel -> transportAction.execute(request, new RestToXContentListener<>(channel));
     }
 }

elasticsearch/src/main/java/org/elasticsearch/xpack/ml/rest/schedulers/RestGetSchedulersAction.java

@@ -11,7 +11,7 @@ import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestController;
 import org.elasticsearch.rest.RestRequest;
-import org.elasticsearch.rest.action.RestStatusToXContentListener;
+import org.elasticsearch.rest.action.RestToXContentListener;
 import org.elasticsearch.xpack.ml.MlPlugin;
 import org.elasticsearch.xpack.ml.action.GetSchedulersAction;
 import org.elasticsearch.xpack.ml.scheduler.SchedulerConfig;
@@ -35,6 +35,6 @@ public class RestGetSchedulersAction extends BaseRestHandler {
     @Override
     protected RestChannelConsumer prepareRequest(RestRequest restRequest, NodeClient client) throws IOException {
         GetSchedulersAction.Request request = new GetSchedulersAction.Request(restRequest.param(SchedulerConfig.ID.getPreferredName()));
-        return channel -> transportGetSchedulersAction.execute(request, new RestStatusToXContentListener<>(channel));
+        return channel -> transportGetSchedulersAction.execute(request, new RestToXContentListener<>(channel));
     }
 }

elasticsearch/src/main/java/org/elasticsearch/xpack/ml/rest/schedulers/RestGetSchedulersStatsAction.java

@@ -11,7 +11,7 @@ import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestController;
 import org.elasticsearch.rest.RestRequest;
-import org.elasticsearch.rest.action.RestStatusToXContentListener;
+import org.elasticsearch.rest.action.RestToXContentListener;
 import org.elasticsearch.xpack.ml.MlPlugin;
 import org.elasticsearch.xpack.ml.action.GetSchedulersStatsAction;
 import org.elasticsearch.xpack.ml.scheduler.SchedulerConfig;
@@ -36,6 +36,6 @@ public class RestGetSchedulersStatsAction extends BaseRestHandler {
     protected RestChannelConsumer prepareRequest(RestRequest restRequest, NodeClient client) throws IOException {
         GetSchedulersStatsAction.Request request = new GetSchedulersStatsAction.Request(
                 restRequest.param(SchedulerConfig.ID.getPreferredName()));
-        return channel -> transportGetSchedulersStatsAction.execute(request, new RestStatusToXContentListener<>(channel));
+        return channel -> transportGetSchedulersStatsAction.execute(request, new RestToXContentListener<>(channel));
     }
 }

elasticsearch/src/test/java/org/elasticsearch/xpack/ml/integration/MlJobIT.java

@@ -55,7 +55,7 @@ public class MlJobIT extends ESRestTestCase {
                 () -> client().performRequest("get", MlPlugin.BASE_PATH + "anomaly_detectors/non-existing-job/_stats"));
 
         assertThat(e.getResponse().getStatusLine().getStatusCode(), equalTo(404));
-        assertThat(e.getMessage(), containsString("Could not find requested jobs"));
+        assertThat(e.getMessage(), containsString("No known job with id 'non-existing-job'"));
     }
 
     public void testGetJob_GivenJobExists() throws Exception {

elasticsearch/src/test/resources/rest-api-spec/test/get_lists.yaml

@@ -0,0 +1,19 @@
+---
+"Test get all lists given no list exists":
+
+  - do:
+      xpack.ml.put_list:
+        body:  >
+          {
+            "id": "foo",
+            "items": ["abc", "xyz"]
+          }
+
+  - do:
+      xpack.ml.delete_list:
+        list_id: "foo"
+
+  - do:
+      xpack.ml.get_lists: {}
+  - match: { count: 0 }
+  - match: { lists: [] }

elasticsearch/src/test/resources/rest-api-spec/test/jobs_crud.yaml

@@ -1,5 +1,21 @@
+---
+"Test get all jobs and stats given no job exists":
+
+  - do:
+      xpack.ml.get_jobs:
+        job_id: "_all"
+  - match: { count: 0 }
+  - match: { jobs: [] }
+
+  - do:
+      xpack.ml.get_jobs_stats:
+        job_id: "_all"
+  - match: { count: 0 }
+  - match: { jobs: [] }
+
 ---
 "Test job crud apis":
+
   - do:
       xpack.ml.put_job:
         job_id: farequote

elasticsearch/src/test/resources/rest-api-spec/test/schedulers_crud.yaml

@@ -31,6 +31,22 @@ setup:
                 "time_format":"epoch"
             }
           }
+
+---
+"Test get all schedulers and stats given no scheduler exists":
+
+  - do:
+      xpack.ml.get_schedulers:
+        scheduler_id: "_all"
+  - match: { count: 0 }
+  - match: { schedulers: [] }
+
+  - do:
+      xpack.ml.get_schedulers_stats:
+        scheduler_id: "_all"
+  - match: { count: 0 }
+  - match: { schedulers: [] }
+
 ---
 "Test put scheduler referring to missing job_id":
   - do: