[Backport 2.x] Implement segment replication event cancellation.

CHANGELOG.md

@@ -41,6 +41,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 ### Fixed
 - PR reference to checkout code for changelog verifier ([#4296](https://github.com/opensearch-project/OpenSearch/pull/4296))
 - Restore using the class ClusterInfoRequest and ClusterInfoRequestBuilder from package 'org.opensearch.action.support.master.info' for subclasses ([#4324](https://github.com/opensearch-project/OpenSearch/pull/4324))
+- Fixed cancellation of segment replication events ([#4225](https://github.com/opensearch-project/OpenSearch/pull/4225))
 
 ### Security
 

server/src/main/java/org/opensearch/indices/cluster/IndicesClusterStateService.java

@@ -81,6 +81,7 @@
 import org.opensearch.indices.recovery.PeerRecoveryTargetService;
 import org.opensearch.indices.recovery.RecoveryListener;
 import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.indices.replication.SegmentReplicationSourceService;
 import org.opensearch.indices.replication.SegmentReplicationTargetService;
 import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
 import org.opensearch.indices.replication.common.ReplicationState;
@@ -152,6 +153,7 @@ public IndicesClusterStateService(
         final ThreadPool threadPool,
         final PeerRecoveryTargetService recoveryTargetService,
         final SegmentReplicationTargetService segmentReplicationTargetService,
+        final SegmentReplicationSourceService segmentReplicationSourceService,
         final ShardStateAction shardStateAction,
         final NodeMappingRefreshAction nodeMappingRefreshAction,
         final RepositoriesService repositoriesService,
@@ -170,6 +172,7 @@ public IndicesClusterStateService(
             threadPool,
             checkpointPublisher,
             segmentReplicationTargetService,
+            segmentReplicationSourceService,
             recoveryTargetService,
             shardStateAction,
             nodeMappingRefreshAction,
@@ -191,6 +194,7 @@ public IndicesClusterStateService(
         final ThreadPool threadPool,
         final SegmentReplicationCheckpointPublisher checkpointPublisher,
         final SegmentReplicationTargetService segmentReplicationTargetService,
+        final SegmentReplicationSourceService segmentReplicationSourceService,
         final PeerRecoveryTargetService recoveryTargetService,
         final ShardStateAction shardStateAction,
         final NodeMappingRefreshAction nodeMappingRefreshAction,
@@ -211,6 +215,7 @@ public IndicesClusterStateService(
         // if segrep feature flag is not enabled, don't wire the target serivce as an IndexEventListener.
         if (FeatureFlags.isEnabled(FeatureFlags.REPLICATION_TYPE)) {
             indexEventListeners.add(segmentReplicationTargetService);
+            indexEventListeners.add(segmentReplicationSourceService);
         }
         this.builtInIndexListener = Collections.unmodifiableList(indexEventListeners);
         this.indicesService = indicesService;

server/src/main/java/org/opensearch/indices/replication/OngoingSegmentReplications.java

@@ -37,7 +37,6 @@
  * @opensearch.internal
  */
 class OngoingSegmentReplications {
-
     private final RecoverySettings recoverySettings;
     private final IndicesService indicesService;
     private final Map<ReplicationCheckpoint, CopyState> copyStateMap;
@@ -161,14 +160,27 @@ synchronized void cancel(IndexShard shard, String reason) {
         cancelHandlers(handler -> handler.getCopyState().getShard().shardId().equals(shard.shardId()), reason);
     }
 
+    /**
+     * Cancel all Replication events for the given allocation ID, intended to be called when a primary is shutting down.
+     *
+     * @param allocationId  {@link String} - Allocation ID.
+     * @param reason {@link String} - Reason for the cancel
+     */
+    synchronized void cancel(String allocationId, String reason) {
+        final SegmentReplicationSourceHandler handler = allocationIdToHandlers.remove(allocationId);
+        if (handler != null) {
+            handler.cancel(reason);
+            removeCopyState(handler.getCopyState());
+        }
+    }
+
     /**
      * Cancel any ongoing replications for a given {@link DiscoveryNode}
      *
      * @param node {@link DiscoveryNode} node for which to cancel replication events.
      */
     void cancelReplication(DiscoveryNode node) {
         cancelHandlers(handler -> handler.getTargetNode().equals(node), "Node left");
-
     }
 
     /**
@@ -243,11 +255,7 @@ private void cancelHandlers(Predicate<? super SegmentReplicationSourceHandler> p
             .map(SegmentReplicationSourceHandler::getAllocationId)
             .collect(Collectors.toList());
         for (String allocationId : allocationIds) {
-            final SegmentReplicationSourceHandler handler = allocationIdToHandlers.remove(allocationId);
-            if (handler != null) {
-                handler.cancel(reason);
-                removeCopyState(handler.getCopyState());
-            }
+            cancel(allocationId, reason);
         }
     }
 }

server/src/main/java/org/opensearch/indices/replication/PrimaryShardReplicationSource.java

@@ -87,4 +87,10 @@ public void getSegmentFiles(
         );
         transportClient.executeRetryableAction(GET_SEGMENT_FILES, request, responseListener, reader);
     }
+
+    @Override
+    public void cancel() {
+        transportClient.cancel();
+    }
+
 }

server/src/main/java/org/opensearch/indices/replication/SegmentReplicationSource.java

@@ -9,6 +9,7 @@
 package org.opensearch.indices.replication;
 
 import org.opensearch.action.ActionListener;
+import org.opensearch.common.util.CancellableThreads.ExecutionCancelledException;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.store.StoreFileMetadata;
 import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
@@ -47,4 +48,9 @@ void getSegmentFiles(
         Store store,
         ActionListener<GetSegmentFilesResponse> listener
     );
+
+    /**
+     * Cancel any ongoing requests, should resolve any ongoing listeners with onFailure with a {@link ExecutionCancelledException}.
+     */
+    default void cancel() {}
 }

server/src/main/java/org/opensearch/indices/replication/SegmentReplicationSourceHandler.java

@@ -113,6 +113,16 @@ public synchronized void sendFiles(GetSegmentFilesRequest request, ActionListene
         final Closeable releaseResources = () -> IOUtils.close(resources);
         try {
             timer.start();
+            cancellableThreads.setOnCancel((reason, beforeCancelEx) -> {
+                final RuntimeException e = new CancellableThreads.ExecutionCancelledException(
+                    "replication was canceled reason [" + reason + "]"
+                );
+                if (beforeCancelEx != null) {
+                    e.addSuppressed(beforeCancelEx);
+                }
+                IOUtils.closeWhileHandlingException(releaseResources, () -> future.onFailure(e));
+                throw e;
+            });
             final Consumer<Exception> onFailure = e -> {
                 assert Transports.assertNotTransportThread(SegmentReplicationSourceHandler.this + "[onFailure]");
                 IOUtils.closeWhileHandlingException(releaseResources, () -> future.onFailure(e));
@@ -153,6 +163,7 @@ public synchronized void sendFiles(GetSegmentFilesRequest request, ActionListene
             final MultiChunkTransfer<StoreFileMetadata, SegmentFileTransferHandler.FileChunk> transfer = segmentFileTransferHandler
                 .createTransfer(shard.store(), storeFileMetadata, () -> 0, sendFileStep);
             resources.add(transfer);
+            cancellableThreads.checkForCancel();
             transfer.start();
 
             sendFileStep.whenComplete(r -> {

server/src/main/java/org/opensearch/indices/replication/SegmentReplicationSourceService.java

@@ -15,6 +15,7 @@
 import org.opensearch.cluster.ClusterChangedEvent;
 import org.opensearch.cluster.ClusterStateListener;
 import org.opensearch.cluster.node.DiscoveryNode;
+import org.opensearch.cluster.routing.ShardRouting;
 import org.opensearch.cluster.service.ClusterService;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.component.AbstractLifecycleComponent;
@@ -42,7 +43,25 @@
  *
  * @opensearch.internal
  */
-public final class SegmentReplicationSourceService extends AbstractLifecycleComponent implements ClusterStateListener, IndexEventListener {
+public class SegmentReplicationSourceService extends AbstractLifecycleComponent implements ClusterStateListener, IndexEventListener {
+
+    // Empty Implementation, only required while Segment Replication is under feature flag.
+    public static final SegmentReplicationSourceService NO_OP = new SegmentReplicationSourceService() {
+        @Override
+        public void clusterChanged(ClusterChangedEvent event) {
+            // NoOp;
+        }
+
+        @Override
+        public void beforeIndexShardClosed(ShardId shardId, IndexShard indexShard, Settings indexSettings) {
+            // NoOp;
+        }
+
+        @Override
+        public void shardRoutingChanged(IndexShard indexShard, @Nullable ShardRouting oldRouting, ShardRouting newRouting) {
+            // NoOp;
+        }
+    };
 
     private static final Logger logger = LogManager.getLogger(SegmentReplicationSourceService.class);
     private final RecoverySettings recoverySettings;
@@ -62,6 +81,14 @@ public static class Actions {
 
     private final OngoingSegmentReplications ongoingSegmentReplications;
 
+    // Used only for empty implementation.
+    private SegmentReplicationSourceService() {
+        recoverySettings = null;
+        ongoingSegmentReplications = null;
+        transportService = null;
+        indicesService = null;
+    }
+
     public SegmentReplicationSourceService(
         IndicesService indicesService,
         TransportService transportService,
@@ -163,10 +190,25 @@ protected void doClose() throws IOException {
 
     }
 
+    /**
+     *
+     * Cancels any replications on this node to a replica shard that is about to be closed.
+     */
     @Override
     public void beforeIndexShardClosed(ShardId shardId, @Nullable IndexShard indexShard, Settings indexSettings) {
         if (indexShard != null) {
             ongoingSegmentReplications.cancel(indexShard, "shard is closed");
         }
     }
+
+    /**
+     * Cancels any replications on this node to a replica that has been promoted as primary.
+     */
+    @Override
+    public void shardRoutingChanged(IndexShard indexShard, @Nullable ShardRouting oldRouting, ShardRouting newRouting) {
+        if (indexShard != null && oldRouting.primary() == false && newRouting.primary()) {
+            ongoingSegmentReplications.cancel(indexShard.routingEntry().allocationId().getId(), "Relocating primary shard.");
+        }
+    }
+
 }

server/src/main/java/org/opensearch/indices/replication/SegmentReplicationState.java

@@ -35,7 +35,8 @@ public enum Stage {
         GET_CHECKPOINT_INFO((byte) 3),
         FILE_DIFF((byte) 4),
         GET_FILES((byte) 5),
-        FINALIZE_REPLICATION((byte) 6);
+        FINALIZE_REPLICATION((byte) 6),
+        CANCELLED((byte) 7);
 
         private static final Stage[] STAGES = new Stage[Stage.values().length];
 
@@ -118,6 +119,10 @@ protected void validateAndSetStage(Stage expected, Stage next) {
                 "can't move replication to stage [" + next + "]. current stage: [" + stage + "] (expected [" + expected + "])"
             );
         }
+        stopTimersAndSetStage(next);
+    }
+
+    private void stopTimersAndSetStage(Stage next) {
         // save the timing data for the current step
         stageTimer.stop();
         timingData.add(new Tuple<>(stage.name(), stageTimer.time()));
@@ -155,6 +160,14 @@ public void setStage(Stage stage) {
                 overallTimer.stop();
                 timingData.add(new Tuple<>("OVERALL", overallTimer.time()));
                 break;
+            case CANCELLED:
+                if (this.stage == Stage.DONE) {
+                    throw new IllegalStateException("can't move replication to Cancelled state from Done.");
+                }
+                stopTimersAndSetStage(Stage.CANCELLED);
+                overallTimer.stop();
+                timingData.add(new Tuple<>("OVERALL", overallTimer.time()));
+                break;
             default:
                 throw new IllegalArgumentException("unknown SegmentReplicationState.Stage [" + stage + "]");
         }

server/src/main/java/org/opensearch/indices/replication/SegmentReplicationTarget.java

@@ -17,6 +17,7 @@
 import org.apache.lucene.store.ByteBuffersDataInput;
 import org.apache.lucene.store.ByteBuffersIndexInput;
 import org.apache.lucene.store.ChecksumIndexInput;
+import org.opensearch.ExceptionsHelper;
 import org.opensearch.OpenSearchException;
 import org.opensearch.action.ActionListener;
 import org.opensearch.action.StepListener;
@@ -103,7 +104,15 @@ public String description() {
 
     @Override
     public void notifyListener(OpenSearchException e, boolean sendShardFailure) {
-        listener.onFailure(state(), e, sendShardFailure);
+        // Cancellations still are passed to our SegmentReplicationListner as failures, if we have failed because of cancellation
+        // update the stage.
+        final Throwable cancelledException = ExceptionsHelper.unwrap(e, CancellableThreads.ExecutionCancelledException.class);
+        if (cancelledException != null) {
+            state.setStage(SegmentReplicationState.Stage.CANCELLED);
+            listener.onFailure(state(), (CancellableThreads.ExecutionCancelledException) cancelledException, sendShardFailure);
+        } else {
+            listener.onFailure(state(), e, sendShardFailure);
+        }
     }
 
     @Override
@@ -134,13 +143,22 @@ public void writeFileChunk(
      * @param listener {@link ActionListener} listener.
      */
     public void startReplication(ActionListener<Void> listener) {
+        cancellableThreads.setOnCancel((reason, beforeCancelEx) -> {
+            // This method only executes when cancellation is triggered by this node and caught by a call to checkForCancel,
+            // SegmentReplicationSource does not share CancellableThreads.
+            final CancellableThreads.ExecutionCancelledException executionCancelledException =
+                new CancellableThreads.ExecutionCancelledException("replication was canceled reason [" + reason + "]");
+            notifyListener(executionCancelledException, false);
+            throw executionCancelledException;
+        });
         state.setStage(SegmentReplicationState.Stage.REPLICATING);
         final StepListener<CheckpointInfoResponse> checkpointInfoListener = new StepListener<>();
         final StepListener<GetSegmentFilesResponse> getFilesListener = new StepListener<>();
         final StepListener<Void> finalizeListener = new StepListener<>();
 
         logger.trace("[shardId {}] Replica starting replication [id {}]", shardId().getId(), getId());
         // Get list of files to copy from this checkpoint.
+        cancellableThreads.checkForCancel();
         state.setStage(SegmentReplicationState.Stage.GET_CHECKPOINT_INFO);
         source.getCheckpointMetadata(getId(), checkpoint, checkpointInfoListener);
 
@@ -154,6 +172,7 @@ public void startReplication(ActionListener<Void> listener) {
 
     private void getFiles(CheckpointInfoResponse checkpointInfo, StepListener<GetSegmentFilesResponse> getFilesListener)
         throws IOException {
+        cancellableThreads.checkForCancel();
         state.setStage(SegmentReplicationState.Stage.FILE_DIFF);
         final Store.MetadataSnapshot snapshot = checkpointInfo.getSnapshot();
         Store.MetadataSnapshot localMetadata = getMetadataSnapshot();
@@ -188,12 +207,14 @@ private void getFiles(CheckpointInfoResponse checkpointInfo, StepListener<GetSeg
         }
         // always send a req even if not fetching files so the primary can clear the copyState for this shard.
         state.setStage(SegmentReplicationState.Stage.GET_FILES);
+        cancellableThreads.checkForCancel();
         source.getSegmentFiles(getId(), checkpointInfo.getCheckpoint(), filesToFetch, store, getFilesListener);
     }
 
     private void finalizeReplication(CheckpointInfoResponse checkpointInfoResponse, ActionListener<Void> listener) {
-        state.setStage(SegmentReplicationState.Stage.FINALIZE_REPLICATION);
         ActionListener.completeWith(listener, () -> {
+            cancellableThreads.checkForCancel();
+            state.setStage(SegmentReplicationState.Stage.FINALIZE_REPLICATION);
             multiFileWriter.renameAllTempFiles();
             final Store store = store();
             store.incRef();
@@ -261,4 +282,10 @@ Store.MetadataSnapshot getMetadataSnapshot() throws IOException {
         }
         return store.getMetadata(indexShard.getSegmentInfosSnapshot().get());
     }
+
+    @Override
+    protected void onCancel(String reason) {
+        cancellableThreads.cancel(reason);
+        source.cancel();
+    }
 }