[ML-FC] do not allow durations below the bucket span (elastic/x-pack-elasticsearch#3166)

do not allow durations below the bucket span

Original commit: elastic/x-pack-elasticsearch@0e895c1ddd

plugin/src/main/java/org/elasticsearch/xpack/ml/action/ForecastJobAction.java

@@ -26,6 +26,7 @@ import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
+import org.elasticsearch.xpack.ml.job.JobManager;
 import org.elasticsearch.xpack.ml.job.config.Job;
 import org.elasticsearch.xpack.ml.job.process.autodetect.AutodetectProcessManager;
 import org.elasticsearch.xpack.ml.job.process.autodetect.params.ForecastParams;
@@ -34,6 +35,8 @@ import org.elasticsearch.xpack.ml.job.results.Forecast;
 import java.io.IOException;
 import java.util.Objects;
 
+import static org.elasticsearch.xpack.ml.action.ForecastJobAction.Request.DURATION;
+
 public class ForecastJobAction extends Action<ForecastJobAction.Request, ForecastJobAction.Response, ForecastJobAction.RequestBuilder> {
 
     public static final ForecastJobAction INSTANCE = new ForecastJobAction();
@@ -244,13 +247,16 @@ public class ForecastJobAction extends Action<ForecastJobAction.Request, Forecas
 
     public static class TransportAction extends TransportJobTaskAction<Request, Response> {
 
+        private final JobManager jobManager;
+
         @Inject
         public TransportAction(Settings settings, TransportService transportService, ThreadPool threadPool, ClusterService clusterService,
                 ActionFilters actionFilters, IndexNameExpressionResolver indexNameExpressionResolver,
-                AutodetectProcessManager processManager) {
+                JobManager jobManager, AutodetectProcessManager processManager) {
             super(settings, ForecastJobAction.NAME, threadPool, clusterService, transportService, actionFilters,
                     indexNameExpressionResolver, ForecastJobAction.Request::new, ForecastJobAction.Response::new, ThreadPool.Names.SAME,
                     processManager);
+            this.jobManager = jobManager;
             // ThreadPool.Names.SAME, because operations is executed by autodetect worker thread
         }
 
@@ -265,6 +271,16 @@ public class ForecastJobAction extends Action<ForecastJobAction.Request, Forecas
         protected void taskOperation(Request request, OpenJobAction.JobTask task, ActionListener<Response> listener) {
             ForecastParams.Builder paramsBuilder = ForecastParams.builder();
             if (request.getDuration() != null) {
+                TimeValue duration = request.getDuration();
+                TimeValue bucketSpan = jobManager.getJobOrThrowIfUnknown(task.getJobId()).getAnalysisConfig().getBucketSpan();
+
+                if (duration.compareTo(bucketSpan) < 0) {
+                    throw new IllegalArgumentException(
+                            "[" + DURATION.getPreferredName()
+                            + "] must be greater or equal to the bucket span: ["
+                            + duration.getStringRep() + "/" + bucketSpan.getStringRep() + "]");
+                }
+
                 paramsBuilder.duration(request.getDuration());
             }
             if (request.getExpiresIn() != null) {

plugin/src/test/java/org/elasticsearch/xpack/ml/integration/ForecastIT.java

@@ -5,6 +5,7 @@
  */
 package org.elasticsearch.xpack.ml.integration;
 
+import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.xpack.ml.job.config.AnalysisConfig;
 import org.elasticsearch.xpack.ml.job.config.DataDescription;
@@ -134,6 +135,27 @@ public class ForecastIT extends MlNativeAutodetectIntegTestCase {
         }
     }
 
+    public void testDurationCannotBeLessThanBucketSpan() throws Exception {
+        Detector.Builder detector = new Detector.Builder("mean", "value");
+
+        TimeValue bucketSpan = TimeValue.timeValueHours(1);
+        AnalysisConfig.Builder analysisConfig = new AnalysisConfig.Builder(Collections.singletonList(detector.build()));
+        analysisConfig.setBucketSpan(bucketSpan);
+        DataDescription.Builder dataDescription = new DataDescription.Builder();
+        dataDescription.setTimeFormat("epoch");
+        Job.Builder job = new Job.Builder("forecast-it-test-duration-bucket-span");
+        job.setAnalysisConfig(analysisConfig);
+        job.setDataDescription(dataDescription);
+
+        registerJob(job);
+        putJob(job);
+        openJob(job.getId());
+        ElasticsearchException e = expectThrows(ElasticsearchException.class,() -> forecast(job.getId(),
+                TimeValue.timeValueMinutes(10), null));
+        assertThat(e.getMessage(),
+                equalTo("java.lang.IllegalArgumentException: [duration] must be greater or equal to the bucket span: [10m/1h]"));
+    }
+
     private static Map<String, Object> createRecord(long timestamp, double value) {
         Map<String, Object> record = new HashMap<>();
         record.put("time", timestamp);