Pass TranslogRecoveryRunner to engine from outside

This commit allows us to use different TranslogRecoveryRunner when recovering an engine from its local translog. This change is a prerequisite for the commit-based rollback PR (elastic#32867).

See elastic#32867 (comment)

server/src/main/java/org/elasticsearch/index/engine/Engine.java

@@ -1642,9 +1642,10 @@ public interface Warmer {
      * Performs recovery from the transaction log up to {@code recoverUpToSeqNo} (inclusive).
      * This operation will close the engine if the recovery fails.
      *
-     * @param recoverUpToSeqNo the upper bound, inclusive, of sequence number to be recovered
+     * @param translogRecoveryRunner the translog recovery runner
+     * @param recoverUpToSeqNo       the upper bound, inclusive, of sequence number to be recovered
      */
-    public abstract Engine recoverFromTranslog(long recoverUpToSeqNo) throws IOException;
+    public abstract Engine recoverFromTranslog(TranslogRecoveryRunner translogRecoveryRunner, long recoverUpToSeqNo) throws IOException;
 
     /**
      * Do not replay translog operations, but make the engine be ready.
@@ -1662,4 +1663,9 @@ public boolean isRecovering() {
      * Tries to prune buffered deletes from the version map.
      */
     public abstract void maybePruneDeletes();
+
+    @FunctionalInterface
+    public interface TranslogRecoveryRunner {
+        int run(Engine engine, Translog.Snapshot snapshot) throws IOException;
+    }
 }

server/src/main/java/org/elasticsearch/index/engine/EngineConfig.java

@@ -37,13 +37,11 @@
 import org.elasticsearch.index.mapper.ParsedDocument;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.index.store.Store;
-import org.elasticsearch.index.translog.Translog;
 import org.elasticsearch.index.translog.TranslogConfig;
 import org.elasticsearch.indices.IndexingMemoryController;
 import org.elasticsearch.indices.breaker.CircuitBreakerService;
 import org.elasticsearch.threadpool.ThreadPool;
 
-import java.io.IOException;
 import java.util.List;
 import java.util.function.LongSupplier;
 
@@ -76,7 +74,6 @@ public final class EngineConfig {
     private final List<ReferenceManager.RefreshListener> internalRefreshListener;
     @Nullable
     private final Sort indexSort;
-    private final TranslogRecoveryRunner translogRecoveryRunner;
     @Nullable
     private final CircuitBreakerService circuitBreakerService;
     private final LongSupplier globalCheckpointSupplier;
@@ -127,9 +124,8 @@ public EngineConfig(ShardId shardId, String allocationId, ThreadPool threadPool,
                         TranslogConfig translogConfig, TimeValue flushMergesAfter,
                         List<ReferenceManager.RefreshListener> externalRefreshListener,
                         List<ReferenceManager.RefreshListener> internalRefreshListener, Sort indexSort,
-                        TranslogRecoveryRunner translogRecoveryRunner, CircuitBreakerService circuitBreakerService,
-                        LongSupplier globalCheckpointSupplier, LongSupplier primaryTermSupplier,
-                        TombstoneDocSupplier tombstoneDocSupplier) {
+                        CircuitBreakerService circuitBreakerService, LongSupplier globalCheckpointSupplier,
+                        LongSupplier primaryTermSupplier, TombstoneDocSupplier tombstoneDocSupplier) {
         this.shardId = shardId;
         this.allocationId = allocationId;
         this.indexSettings = indexSettings;
@@ -163,7 +159,6 @@ public EngineConfig(ShardId shardId, String allocationId, ThreadPool threadPool,
         this.externalRefreshListener = externalRefreshListener;
         this.internalRefreshListener = internalRefreshListener;
         this.indexSort = indexSort;
-        this.translogRecoveryRunner = translogRecoveryRunner;
         this.circuitBreakerService = circuitBreakerService;
         this.globalCheckpointSupplier = globalCheckpointSupplier;
         this.primaryTermSupplier = primaryTermSupplier;
@@ -324,18 +319,6 @@ public TranslogConfig getTranslogConfig() {
      */
     public TimeValue getFlushMergesAfter() { return flushMergesAfter; }
 
-    @FunctionalInterface
-    public interface TranslogRecoveryRunner {
-        int run(Engine engine, Translog.Snapshot snapshot) throws IOException;
-    }
-
-    /**
-     * Returns a runner that implements the translog recovery from the given snapshot
-     */
-    public TranslogRecoveryRunner getTranslogRecoveryRunner() {
-        return translogRecoveryRunner;
-    }
-
     /**
      * The refresh listeners to add to Lucene for externally visible refreshes
      */

server/src/main/java/org/elasticsearch/index/engine/InternalEngine.java

@@ -393,15 +393,15 @@ private void bootstrapAppendOnlyInfoFromWriter(IndexWriter writer) {
     }
 
     @Override
-    public InternalEngine recoverFromTranslog(long recoverUpToSeqNo) throws IOException {
+    public InternalEngine recoverFromTranslog(TranslogRecoveryRunner translogRecoveryRunner, long recoverUpToSeqNo) throws IOException {
         flushLock.lock();
         try (ReleasableLock lock = readLock.acquire()) {
             ensureOpen();
             if (pendingTranslogRecovery.get() == false) {
                 throw new IllegalStateException("Engine has already been recovered");
             }
             try {
-                recoverFromTranslogInternal(recoverUpToSeqNo);
+                recoverFromTranslogInternal(translogRecoveryRunner, recoverUpToSeqNo);
             } catch (Exception e) {
                 try {
                     pendingTranslogRecovery.set(true); // just play safe and never allow commits on this see #ensureCanFlush
@@ -423,13 +423,13 @@ public void skipTranslogRecovery() {
         pendingTranslogRecovery.set(false); // we are good - now we can commit
     }
 
-    private void recoverFromTranslogInternal(long recoverUpToSeqNo) throws IOException {
+    private void recoverFromTranslogInternal(TranslogRecoveryRunner translogRecoveryRunner, long recoverUpToSeqNo) throws IOException {
         Translog.TranslogGeneration translogGeneration = translog.getGeneration();
         final int opsRecovered;
         final long translogFileGen = Long.parseLong(lastCommittedSegmentInfos.getUserData().get(Translog.TRANSLOG_GENERATION_KEY));
         try (Translog.Snapshot snapshot = translog.newSnapshotFromGen(
             new Translog.TranslogGeneration(translog.getTranslogUUID(), translogFileGen), recoverUpToSeqNo)) {
-            opsRecovered = config().getTranslogRecoveryRunner().run(this, snapshot);
+            opsRecovered = translogRecoveryRunner.run(this, snapshot);
         } catch (Exception e) {
             throw new EngineException(shardId, "failed to recover from translog", e);
         }

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

@@ -1314,7 +1314,7 @@ int runTranslogRecovery(Engine engine, Translog.Snapshot snapshot) throws IOExce
      **/
     public void openEngineAndRecoverFromTranslog() throws IOException {
         innerOpenEngineAndTranslog();
-        getEngine().recoverFromTranslog(Long.MAX_VALUE);
+        getEngine().recoverFromTranslog(this::runTranslogRecovery, Long.MAX_VALUE);
     }
 
     /**
@@ -2233,7 +2233,7 @@ private EngineConfig newEngineConfig() {
             IndexingMemoryController.SHARD_INACTIVE_TIME_SETTING.get(indexSettings.getSettings()),
             Collections.singletonList(refreshListeners),
             Collections.singletonList(new RefreshMetricUpdater(refreshMetric)),
-            indexSort, this::runTranslogRecovery, circuitBreakerService, replicationTracker, () -> operationPrimaryTerm, tombstoneDocSupplier());
+            indexSort, circuitBreakerService, replicationTracker, () -> operationPrimaryTerm, tombstoneDocSupplier());
     }
 
     /**