Adding CheckpointRefreshListener to trigger when Segment replication …

…is turned on and Primary shard refreshes (#3108)

* Intial PR adding classes and tests related to checkpoint publishing

Signed-off-by: Rishikesh1159 <rishireddy1159@gmail.com>

* Putting a Draft PR with all changes in classes. Testing is still not included in this commit.

Signed-off-by: Rishikesh1159 <rishireddy1159@gmail.com>

* Wiring up index shard to new engine, spotless apply and removing unnecessary tests and logs

Signed-off-by: Rishikesh1159 <rishireddy1159@gmail.com>

* Adding Unit test for checkpointRefreshListener

Signed-off-by: Rishikesh1159 <rishireddy1159@gmail.com>

* Applying spotless check

Signed-off-by: Rishikesh1159 <rishireddy1159@gmail.com>

* Fixing import statements *

Signed-off-by: Rishikesh1159 <rishireddy1159@gmail.com>

* removing unused constructor in index shard

Signed-off-by: Rishikesh1159 <rishireddy1159@gmail.com>

* Addressing comments from last commit

Signed-off-by: Rishikesh1159 <rishireddy1159@gmail.com>

* Adding package-info.java files for two new packages

Signed-off-by: Rishikesh1159 <rishireddy1159@gmail.com>

* Adding test for null checkpoint publisher and addreesing PR comments

Signed-off-by: Rishikesh1159 <rishireddy1159@gmail.com>

* Add docs for indexshardtests and remove shard.refresh

Signed-off-by: Rishikesh1159 <rishireddy1159@gmail.com>

server/src/internalClusterTest/java/org/opensearch/index/shard/IndexShardIT.java

@@ -84,6 +84,7 @@
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.breaker.CircuitBreakerService;
 import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
 import org.opensearch.plugins.Plugin;
 import org.opensearch.search.builder.SearchSourceBuilder;
 import org.opensearch.test.DummyShardLock;
@@ -673,7 +674,8 @@ public static final IndexShard newIndexShard(
             Arrays.asList(listeners),
             () -> {},
             RetentionLeaseSyncer.EMPTY,
-            cbs
+            cbs,
+            SegmentReplicationCheckpointPublisher.EMPTY
         );
     }
 

server/src/main/java/org/opensearch/index/IndexService.java

@@ -94,6 +94,7 @@
 import org.opensearch.indices.fielddata.cache.IndicesFieldDataCache;
 import org.opensearch.indices.mapper.MapperRegistry;
 import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
 import org.opensearch.plugins.IndexStorePlugin;
 import org.opensearch.script.ScriptService;
 import org.opensearch.search.aggregations.support.ValuesSourceRegistry;
@@ -428,7 +429,8 @@ private long getAvgShardSizeInBytes() throws IOException {
     public synchronized IndexShard createShard(
         final ShardRouting routing,
         final Consumer<ShardId> globalCheckpointSyncer,
-        final RetentionLeaseSyncer retentionLeaseSyncer
+        final RetentionLeaseSyncer retentionLeaseSyncer,
+        final SegmentReplicationCheckpointPublisher checkpointPublisher
     ) throws IOException {
         Objects.requireNonNull(retentionLeaseSyncer);
         /*
@@ -530,7 +532,8 @@ public synchronized IndexShard createShard(
                 indexingOperationListeners,
                 () -> globalCheckpointSyncer.accept(shardId),
                 retentionLeaseSyncer,
-                circuitBreakerService
+                circuitBreakerService,
+                this.indexSettings.isSegRepEnabled() && routing.primary() ? checkpointPublisher : null
             );
             eventListener.indexShardStateChanged(indexShard, null, indexShard.state(), "shard created");
             eventListener.afterIndexShardCreated(indexShard);

server/src/main/java/org/opensearch/index/shard/CheckpointRefreshListener.java

@@ -0,0 +1,47 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.index.shard;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+import org.apache.lucene.search.ReferenceManager;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
+
+import java.io.IOException;
+
+/**
+ * A {@link ReferenceManager.RefreshListener} that publishes a checkpoint to be consumed by replicas.
+ * This class is only used with Segment Replication enabled.
+ *
+ * @opensearch.internal
+ */
+public class CheckpointRefreshListener implements ReferenceManager.RefreshListener {
+
+    protected static Logger logger = LogManager.getLogger(CheckpointRefreshListener.class);
+
+    private final IndexShard shard;
+    private final SegmentReplicationCheckpointPublisher publisher;
+
+    public CheckpointRefreshListener(IndexShard shard, SegmentReplicationCheckpointPublisher publisher) {
+        this.shard = shard;
+        this.publisher = publisher;
+    }
+
+    @Override
+    public void beforeRefresh() throws IOException {
+        // Do nothing
+    }
+
+    @Override
+    public void afterRefresh(boolean didRefresh) throws IOException {
+        if (didRefresh) {
+            publisher.publish(shard);
+        }
+    }
+}

server/src/main/java/org/opensearch/index/shard/IndexShard.java

@@ -160,6 +160,9 @@
 import org.opensearch.indices.recovery.RecoveryListener;
 import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.indices.recovery.RecoveryTarget;
+import org.opensearch.indices.replication.checkpoint.PublishCheckpointRequest;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
+import org.opensearch.indices.replication.checkpoint.ReplicationCheckpoint;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.repositories.Repository;
 import org.opensearch.rest.RestStatus;
@@ -299,6 +302,7 @@ Runnable getGlobalCheckpointSyncer() {
     private final AtomicReference<Translog.Location> pendingRefreshLocation = new AtomicReference<>();
     private final RefreshPendingLocationListener refreshPendingLocationListener;
     private volatile boolean useRetentionLeasesInPeerRecovery;
+    private final ReferenceManager.RefreshListener checkpointRefreshListener;
 
     public IndexShard(
         final ShardRouting shardRouting,
@@ -320,7 +324,8 @@ public IndexShard(
         final List<IndexingOperationListener> listeners,
         final Runnable globalCheckpointSyncer,
         final RetentionLeaseSyncer retentionLeaseSyncer,
-        final CircuitBreakerService circuitBreakerService
+        final CircuitBreakerService circuitBreakerService,
+        @Nullable final SegmentReplicationCheckpointPublisher checkpointPublisher
     ) throws IOException {
         super(shardRouting.shardId(), indexSettings);
         assert shardRouting.initializing();
@@ -403,6 +408,11 @@ public boolean shouldCache(Query query) {
         persistMetadata(path, indexSettings, shardRouting, null, logger);
         this.useRetentionLeasesInPeerRecovery = replicationTracker.hasAllPeerRecoveryRetentionLeases();
         this.refreshPendingLocationListener = new RefreshPendingLocationListener();
+        if (checkpointPublisher != null) {
+            this.checkpointRefreshListener = new CheckpointRefreshListener(this, checkpointPublisher);
+        } else {
+            this.checkpointRefreshListener = null;
+        }
     }
 
     public ThreadPool getThreadPool() {
@@ -1363,6 +1373,21 @@ public GatedCloseable<IndexCommit> acquireSafeIndexCommit() throws EngineExcepti
         }
     }
 
+    /**
+     * Returns the lastest Replication Checkpoint that shard received
+     */
+    public ReplicationCheckpoint getLatestReplicationCheckpoint() {
+        return new ReplicationCheckpoint(shardId, 0, 0, 0, 0);
+    }
+
+    /**
+     * Invoked when a new checkpoint is received from a primary shard.  Starts the copy process.
+     */
+    public synchronized void onNewCheckpoint(final PublishCheckpointRequest request) {
+        assert shardRouting.primary() == false;
+        // TODO
+    }
+
     /**
      * gets a {@link Store.MetadataSnapshot} for the current directory. This method is safe to call in all lifecycle of the index shard,
      * without having to worry about the current state of the engine and concurrent flushes.
@@ -3106,6 +3131,13 @@ private EngineConfig newEngineConfig(LongSupplier globalCheckpointSupplier) {
             }
         };
 
+        final List<ReferenceManager.RefreshListener> internalRefreshListener;
+        if (this.checkpointRefreshListener != null) {
+            internalRefreshListener = Arrays.asList(new RefreshMetricUpdater(refreshMetric), checkpointRefreshListener);
+        } else {
+            internalRefreshListener = Collections.singletonList(new RefreshMetricUpdater(refreshMetric));
+        }
+
         return this.engineConfigFactory.newEngineConfig(
             shardId,
             threadPool,
@@ -3122,7 +3154,7 @@ private EngineConfig newEngineConfig(LongSupplier globalCheckpointSupplier) {
             translogConfig,
             IndexingMemoryController.SHARD_INACTIVE_TIME_SETTING.get(indexSettings.getSettings()),
             Arrays.asList(refreshListeners, refreshPendingLocationListener),
-            Collections.singletonList(new RefreshMetricUpdater(refreshMetric)),
+            internalRefreshListener,
             indexSort,
             circuitBreakerService,
             globalCheckpointSupplier,

server/src/main/java/org/opensearch/indices/IndicesModule.java

@@ -41,6 +41,7 @@
 import org.opensearch.common.inject.AbstractModule;
 import org.opensearch.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.common.io.stream.NamedWriteableRegistry.Entry;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.NamedXContentRegistry;
 import org.opensearch.index.mapper.BinaryFieldMapper;
 import org.opensearch.index.mapper.BooleanFieldMapper;
@@ -73,6 +74,7 @@
 import org.opensearch.index.shard.PrimaryReplicaSyncer;
 import org.opensearch.indices.cluster.IndicesClusterStateService;
 import org.opensearch.indices.mapper.MapperRegistry;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
 import org.opensearch.indices.store.IndicesStore;
 import org.opensearch.indices.store.TransportNodesListShardStoreMetadata;
 import org.opensearch.plugins.MapperPlugin;
@@ -278,6 +280,9 @@ protected void configure() {
         bind(RetentionLeaseSyncAction.class).asEagerSingleton();
         bind(RetentionLeaseBackgroundSyncAction.class).asEagerSingleton();
         bind(RetentionLeaseSyncer.class).asEagerSingleton();
+        if (FeatureFlags.isEnabled(FeatureFlags.REPLICATION_TYPE)) {
+            bind(SegmentReplicationCheckpointPublisher.class).asEagerSingleton();
+        }
     }
 
     /**

server/src/main/java/org/opensearch/indices/IndicesService.java

@@ -138,6 +138,7 @@
 import org.opensearch.indices.recovery.PeerRecoveryTargetService;
 import org.opensearch.indices.recovery.RecoveryListener;
 import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
 import org.opensearch.node.Node;
 import org.opensearch.plugins.IndexStorePlugin;
 import org.opensearch.plugins.PluginsService;
@@ -839,6 +840,7 @@ public synchronized void verifyIndexMetadata(IndexMetadata metadata, IndexMetada
     @Override
     public IndexShard createShard(
         final ShardRouting shardRouting,
+        final SegmentReplicationCheckpointPublisher checkpointPublisher,
         final PeerRecoveryTargetService recoveryTargetService,
         final RecoveryListener recoveryListener,
         final RepositoriesService repositoriesService,
@@ -853,7 +855,7 @@ public IndexShard createShard(
         IndexService indexService = indexService(shardRouting.index());
         assert indexService != null;
         RecoveryState recoveryState = indexService.createRecoveryState(shardRouting, targetNode, sourceNode);
-        IndexShard indexShard = indexService.createShard(shardRouting, globalCheckpointSyncer, retentionLeaseSyncer);
+        IndexShard indexShard = indexService.createShard(shardRouting, globalCheckpointSyncer, retentionLeaseSyncer, checkpointPublisher);
         indexShard.addShardFailureCallback(onShardFailure);
         indexShard.startRecovery(recoveryState, recoveryTargetService, recoveryListener, repositoriesService, mapping -> {
             assert recoveryState.getRecoverySource().getType() == RecoverySource.Type.LOCAL_SHARDS

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

@@ -80,6 +80,7 @@
 import org.opensearch.indices.recovery.PeerRecoveryTargetService;
 import org.opensearch.indices.recovery.RecoveryListener;
 import org.opensearch.indices.recovery.RecoveryState;
+import org.opensearch.indices.replication.checkpoint.SegmentReplicationCheckpointPublisher;
 import org.opensearch.indices.replication.common.ReplicationState;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.search.SearchService;
@@ -138,6 +139,8 @@ public class IndicesClusterStateService extends AbstractLifecycleComponent imple
     private final Consumer<ShardId> globalCheckpointSyncer;
     private final RetentionLeaseSyncer retentionLeaseSyncer;
 
+    private final SegmentReplicationCheckpointPublisher checkpointPublisher;
+
     @Inject
     public IndicesClusterStateService(
         final Settings settings,
@@ -153,13 +156,15 @@ public IndicesClusterStateService(
         final SnapshotShardsService snapshotShardsService,
         final PrimaryReplicaSyncer primaryReplicaSyncer,
         final GlobalCheckpointSyncAction globalCheckpointSyncAction,
-        final RetentionLeaseSyncer retentionLeaseSyncer
+        final RetentionLeaseSyncer retentionLeaseSyncer,
+        final SegmentReplicationCheckpointPublisher checkpointPublisher
     ) {
         this(
             settings,
             indicesService,
             clusterService,
             threadPool,
+            checkpointPublisher,
             recoveryTargetService,
             shardStateAction,
             nodeMappingRefreshAction,
@@ -179,6 +184,7 @@ public IndicesClusterStateService(
         final AllocatedIndices<? extends Shard, ? extends AllocatedIndex<? extends Shard>> indicesService,
         final ClusterService clusterService,
         final ThreadPool threadPool,
+        final SegmentReplicationCheckpointPublisher checkpointPublisher,
         final PeerRecoveryTargetService recoveryTargetService,
         final ShardStateAction shardStateAction,
         final NodeMappingRefreshAction nodeMappingRefreshAction,
@@ -191,6 +197,7 @@ public IndicesClusterStateService(
         final RetentionLeaseSyncer retentionLeaseSyncer
     ) {
         this.settings = settings;
+        this.checkpointPublisher = checkpointPublisher;
         this.buildInIndexListener = Arrays.asList(peerRecoverySourceService, recoveryTargetService, searchService, snapshotShardsService);
         this.indicesService = indicesService;
         this.clusterService = clusterService;
@@ -624,6 +631,7 @@ private void createShard(DiscoveryNodes nodes, RoutingTable routingTable, ShardR
             logger.debug("{} creating shard with primary term [{}]", shardRouting.shardId(), primaryTerm);
             indicesService.createShard(
                 shardRouting,
+                checkpointPublisher,
                 recoveryTargetService,
                 new RecoveryListener(shardRouting, primaryTerm, this),
                 repositoriesService,
@@ -981,6 +989,7 @@ U createIndex(IndexMetadata indexMetadata, List<IndexEventListener> builtInIndex
          */
         T createShard(
             ShardRouting shardRouting,
+            SegmentReplicationCheckpointPublisher checkpointPublisher,
             PeerRecoveryTargetService recoveryTargetService,
             RecoveryListener recoveryListener,
             RepositoriesService repositoriesService,