Updating ingest pipeline without changes is no-op

server/src/main/java/org/elasticsearch/action/ingest/PutPipelineTransportAction.java

@@ -25,6 +25,7 @@
 import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.xcontent.XContentHelper;
 import org.elasticsearch.ingest.IngestInfo;
+import org.elasticsearch.ingest.IngestMetadata;
 import org.elasticsearch.ingest.IngestService;
 import org.elasticsearch.ingest.Pipeline;
 import org.elasticsearch.tasks.Task;
@@ -58,22 +59,41 @@ public PutPipelineTransportAction(ThreadPool threadPool, TransportService transp
     @Override
     protected void masterOperation(Task task, PutPipelineRequest request, ClusterState state, ActionListener<AcknowledgedResponse> listener)
             throws Exception {
+
+        Map<String, Object> pipelineConfig = null;
+        IngestMetadata currentIngestMetadata = state.metadata().custom(IngestMetadata.TYPE);
+        if (currentIngestMetadata != null && currentIngestMetadata.getPipelines().containsKey(request.getId())) {
+            pipelineConfig = XContentHelper.convertToMap(request.getSource(), false, request.getXContentType()).v2();
+            var currentPipeline = currentIngestMetadata.getPipelines().get(request.getId());
+            if (currentPipeline.getConfigAsMap().equals(pipelineConfig)) {
+                // existing pipeline matches request pipeline -- no need to update
+                listener.onResponse(AcknowledgedResponse.TRUE);
+                return;
+            }
+        }
+
         if (state.getNodes().getMinNodeVersion().before(Version.V_7_15_0)) {
-            Map<String, Object> pipelineConfig = XContentHelper.convertToMap(request.getSource(), false, request.getXContentType()).v2();
+            pipelineConfig = pipelineConfig == null
+                ? XContentHelper.convertToMap(request.getSource(), false, request.getXContentType()).v2()
+                : pipelineConfig;
             if (pipelineConfig.containsKey(Pipeline.META_KEY)) {
                 throw new IllegalStateException("pipelines with _meta field require minimum node version of " + Version.V_7_15_0);
             }
         }
         NodesInfoRequest nodesInfoRequest = new NodesInfoRequest();
-        nodesInfoRequest.clear()
-            .addMetric(NodesInfoRequest.Metric.INGEST.metricName());
-        client.admin().cluster().nodesInfo(nodesInfoRequest, ActionListener.wrap(nodeInfos -> {
-            Map<DiscoveryNode, IngestInfo> ingestInfos = new HashMap<>();
-            for (NodeInfo nodeInfo : nodeInfos.getNodes()) {
-                ingestInfos.put(nodeInfo.getNode(), nodeInfo.getInfo(IngestInfo.class));
-            }
-            ingestService.putPipeline(ingestInfos, request, listener);
-        }, listener::onFailure));
+        nodesInfoRequest.clear().addMetric(NodesInfoRequest.Metric.INGEST.metricName());
+        client.admin().cluster().nodesInfo(
+            nodesInfoRequest,
+            ActionListener.wrap(
+                nodeInfos -> {
+                    Map<DiscoveryNode, IngestInfo> ingestInfos = new HashMap<>();
+                    for (NodeInfo nodeInfo : nodeInfos.getNodes()) {
+                        ingestInfos.put(nodeInfo.getNode(), nodeInfo.getInfo(IngestInfo.class));
+                    }
+                    ingestService.putPipeline(ingestInfos, request, listener);
+                },
+                listener::onFailure)
+        );
     }
 
     @Override

server/src/test/java/org/elasticsearch/action/ingest/PutPipelineTransportActionTests.java

@@ -0,0 +1,98 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.action.ingest;
+
+import org.elasticsearch.action.ActionListener;
+import org.elasticsearch.action.support.ActionFilters;
+import org.elasticsearch.action.support.master.AcknowledgedResponse;
+import org.elasticsearch.cluster.ClusterName;
+import org.elasticsearch.cluster.ClusterState;
+import org.elasticsearch.cluster.metadata.Metadata;
+import org.elasticsearch.common.bytes.BytesArray;
+import org.elasticsearch.common.util.concurrent.EsExecutors;
+import org.elasticsearch.common.xcontent.XContentType;
+import org.elasticsearch.ingest.IngestMetadata;
+import org.elasticsearch.ingest.IngestService;
+import org.elasticsearch.ingest.PipelineConfiguration;
+import org.elasticsearch.test.ESTestCase;
+import org.elasticsearch.test.client.NoOpNodeClient;
+import org.elasticsearch.threadpool.ThreadPool;
+import org.elasticsearch.transport.TransportService;
+
+import java.util.Map;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicLong;
+
+import static org.hamcrest.Matchers.equalTo;
+import static org.mockito.Matchers.anyString;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class PutPipelineTransportActionTests extends ESTestCase {
+
+    public void testUpdatingPipelineWithoutChangesIsNoOp() throws Exception {
+        var threadPool = mock(ThreadPool.class);
+        when(threadPool.generic()).thenReturn(EsExecutors.DIRECT_EXECUTOR_SERVICE);
+        when(threadPool.executor(anyString())).thenReturn(EsExecutors.DIRECT_EXECUTOR_SERVICE);
+        var client = new NoOpNodeClient(threadPool);
+        var action = new PutPipelineTransportAction(
+            threadPool,
+            mock(TransportService.class),
+            mock(ActionFilters.class),
+            null,
+            mock(IngestService.class),
+            client
+        );
+
+        var pipelineId = randomAlphaOfLength(5);
+        var value = randomAlphaOfLength(5);
+        var pipelineString = "{\"processors\": [{\"set\" : {\"field\": \"_field\", \"value\": \"" + value + "\"}}]}";
+        var existingPipeline = new PipelineConfiguration(pipelineId, new BytesArray(pipelineString), XContentType.JSON);
+        var clusterState = ClusterState.builder(new ClusterName("test"))
+            .metadata(Metadata.builder().putCustom(
+                    IngestMetadata.TYPE,
+                    new IngestMetadata(Map.of(pipelineId, existingPipeline))
+                ).build()
+            ).build();
+
+        CountDownLatch latch = new CountDownLatch(1);
+        var listener = new ActionListener<AcknowledgedResponse>() {
+            final AtomicLong successCount = new AtomicLong(0);
+            final AtomicLong failureCount = new AtomicLong(0);
+
+            @Override
+            public void onResponse(AcknowledgedResponse acknowledgedResponse) {
+                successCount.incrementAndGet();
+                latch.countDown();
+            }
+
+            @Override
+            public void onFailure(Exception e) {
+                failureCount.incrementAndGet();
+                latch.countDown();
+            }
+
+            public long getSuccessCount() {
+                return successCount.get();
+            }
+
+            public long getFailureCount() {
+                return failureCount.get();
+            }
+        };
+
+        var request = new PutPipelineRequest(pipelineId, new BytesArray(pipelineString), XContentType.JSON);
+        action.masterOperation(null, request, clusterState, listener);
+        latch.await();
+
+        assertThat(client.getExecutionCount(), equalTo(0L));
+        assertThat(listener.getSuccessCount(), equalTo(1L));
+        assertThat(listener.getFailureCount(), equalTo(0L));
+    }
+}

test/framework/src/main/java/org/elasticsearch/test/client/NoOpNodeClient.java

@@ -28,6 +28,7 @@
 
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicLong;
 import java.util.function.Supplier;
 
 /**
@@ -39,6 +40,8 @@
  */
 public class NoOpNodeClient extends NodeClient {
 
+    private final AtomicLong executionCount = new AtomicLong(0);
+
     /**
      * Build with {@link ThreadPool}. This {@linkplain ThreadPool} is terminated on {@link #close()}.
      */
@@ -56,6 +59,7 @@ public NoOpNodeClient(String testName) {
     @Override
     public <Request extends ActionRequest, Response extends ActionResponse>
     void doExecute(ActionType<Response> action, Request request, ActionListener<Response> listener) {
+        executionCount.incrementAndGet();
         listener.onResponse(null);
     }
 
@@ -74,13 +78,15 @@ public void initialize(
     @Override
     public <Request extends ActionRequest, Response extends ActionResponse>
     Task executeLocally(ActionType<Response> action, Request request, ActionListener<Response> listener) {
+        executionCount.incrementAndGet();
         listener.onResponse(null);
         return null;
     }
 
     @Override
     public <Request extends ActionRequest, Response extends ActionResponse>
     Task executeLocally(ActionType<Response> action, Request request, TaskListener<Response> listener) {
+        executionCount.incrementAndGet();
         listener.onResponse(null, null);
         return null;
     }
@@ -103,4 +109,8 @@ public void close() {
             throw new ElasticsearchException(e.getMessage(), e);
         }
     }
+
+    public long getExecutionCount() {
+        return executionCount.get();
+    }
 }