Add indexer interface for shard interaction with underlying engines

CHANGELOG.md

@@ -21,6 +21,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - WLM group custom search settings - groundwork and timeout ([#20536](https://github.com/opensearch-project/OpenSearch/issues/20536))
 - Expose JVM runtime metrics via telemetry framework ([#20844](https://github.com/opensearch-project/OpenSearch/pull/20844))
 - Add intra segment support for single-value metric aggregations ([#20503](https://github.com/opensearch-project/OpenSearch/pull/20503))
+- Add support for enabling pluggable data formats, starting with phase-1 of decoupling shard from engine, and introducing basic abstractions ([#20675](https://github.com/opensearch-project/OpenSearch/pull/20675))
 
 ### Changed
 - Make telemetry `Tags` immutable ([#20788](https://github.com/opensearch-project/OpenSearch/pull/20788))

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

@@ -74,6 +74,7 @@
 import org.opensearch.index.VersionType;
 import org.opensearch.index.engine.CommitStats;
 import org.opensearch.index.engine.Engine;
+import org.opensearch.index.engine.EngineBackedIndexer;
 import org.opensearch.index.engine.MergedSegmentWarmerFactory;
 import org.opensearch.index.engine.NoOpEngine;
 import org.opensearch.index.flush.FlushStats;
@@ -852,7 +853,7 @@ public void testNoOpEngineFactoryTakesPrecedence() {
         final IndexService indexService = indicesService.indexServiceSafe(indexMetadata.getIndex());
 
         for (IndexShard indexShard : indexService) {
-            assertThat(indexShard.getEngine(), instanceOf(NoOpEngine.class));
+            assertThat(((EngineBackedIndexer) (indexShard.getIndexer())).getEngine(), instanceOf(NoOpEngine.class));
         }
     }
 

server/src/internalClusterTest/java/org/opensearch/snapshots/SharedClusterSnapshotRestoreIT.java

@@ -103,7 +103,7 @@
 
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
 import static org.opensearch.cluster.routing.allocation.decider.MaxRetryAllocationDecider.SETTING_ALLOCATION_MAX_RETRY;
-import static org.opensearch.index.shard.IndexShardTests.getEngineFromShard;
+import static org.opensearch.index.shard.IndexShardTestCase.getEngine;
 import static org.opensearch.indices.recovery.RecoverySettings.INDICES_RECOVERY_MAX_BYTES_PER_SEC_SETTING;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
 import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAllSuccessful;
@@ -2052,7 +2052,7 @@ public void testSnapshottingWithMissingSequenceNumbers() {
         final Index index = resolveIndex(indexName);
         final IndexShard primary = internalCluster().getInstance(IndicesService.class, dataNode).getShardOrNull(new ShardId(index, 0));
         // create a gap in the sequence numbers
-        EngineTestCase.generateNewSeqNo(getEngineFromShard(primary));
+        EngineTestCase.generateNewSeqNo(getEngine(primary));
 
         for (int i = 5; i < 10; i++) {
             index(indexName, "_doc", Integer.toString(i), "foo", "bar" + i);