Populate RecoveryState details for shallow snapshot restore (opensearch-project#15353)

---------
Signed-off-by: Lakshya Taragi <lakshya.taragi@gmail.com>

Author: ltaragi

server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteRestoreSnapshotIT.java

@@ -13,12 +13,14 @@
 import org.opensearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
 import org.opensearch.action.admin.cluster.snapshots.restore.RestoreSnapshotResponse;
 import org.opensearch.action.admin.indices.delete.DeleteIndexRequest;
+import org.opensearch.action.admin.indices.recovery.RecoveryResponse;
 import org.opensearch.action.delete.DeleteResponse;
 import org.opensearch.action.support.PlainActionFuture;
 import org.opensearch.client.Client;
 import org.opensearch.client.Requests;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.routing.RecoverySource;
 import org.opensearch.common.Nullable;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.io.PathUtils;
@@ -34,6 +36,7 @@
 import org.opensearch.index.shard.IndexShard;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.RemoteStoreSettings;
+import org.opensearch.indices.recovery.RecoveryState;
 import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.repositories.RepositoriesService;
 import org.opensearch.repositories.Repository;
@@ -73,6 +76,7 @@
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.greaterThanOrEqualTo;
+import static org.hamcrest.Matchers.lessThanOrEqualTo;
 
 @OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
 public class RemoteRestoreSnapshotIT extends AbstractSnapshotIntegTestCase {
@@ -589,6 +593,37 @@ public void testRestoreShallowSnapshotRepository() throws ExecutionException, In
         ensureGreen(restoredIndexName1);
         assertDocsPresentInIndex(client, restoredIndexName1, numDocsInIndex1);
 
+        // ensure recovery details are non-zero
+        RecoveryResponse recoveryResponse = client().admin().indices().prepareRecoveries(restoredIndexName1).execute().actionGet();
+        assertEquals(1, recoveryResponse.getTotalShards());
+        assertEquals(1, recoveryResponse.getSuccessfulShards());
+        assertEquals(0, recoveryResponse.getFailedShards());
+        assertEquals(1, recoveryResponse.shardRecoveryStates().size());
+        assertTrue(recoveryResponse.shardRecoveryStates().containsKey(restoredIndexName1));
+        assertEquals(1, recoveryResponse.shardRecoveryStates().get(restoredIndexName1).size());
+
+        RecoveryState recoveryState = recoveryResponse.shardRecoveryStates().get(restoredIndexName1).get(0);
+        assertEquals(RecoveryState.Stage.DONE, recoveryState.getStage());
+        assertEquals(0, recoveryState.getShardId().getId());
+        assertTrue(recoveryState.getPrimary());
+        assertEquals(RecoverySource.Type.SNAPSHOT, recoveryState.getRecoverySource().getType());
+        assertThat(recoveryState.getIndex().time(), greaterThanOrEqualTo(0L));
+
+        // ensure populated file details
+        assertTrue(recoveryState.getIndex().totalFileCount() > 0);
+        assertTrue(recoveryState.getIndex().totalRecoverFiles() > 0);
+        assertTrue(recoveryState.getIndex().recoveredFileCount() > 0);
+        assertThat(recoveryState.getIndex().recoveredFilesPercent(), greaterThanOrEqualTo(0.0f));
+        assertThat(recoveryState.getIndex().recoveredFilesPercent(), lessThanOrEqualTo(100.0f));
+        assertFalse(recoveryState.getIndex().fileDetails().isEmpty());
+
+        // ensure populated bytes details
+        assertTrue(recoveryState.getIndex().recoveredBytes() > 0L);
+        assertTrue(recoveryState.getIndex().totalBytes() > 0L);
+        assertTrue(recoveryState.getIndex().totalRecoverBytes() > 0L);
+        assertThat(recoveryState.getIndex().recoveredBytesPercent(), greaterThanOrEqualTo(0.0f));
+        assertThat(recoveryState.getIndex().recoveredBytesPercent(), lessThanOrEqualTo(100.0f));
+
         // indexing some new docs and validating
         indexDocuments(client, restoredIndexName1, numDocsInIndex1, numDocsInIndex1 + 2);
         ensureGreen(restoredIndexName1);

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

@@ -5117,10 +5117,23 @@ public void syncSegmentsFromGivenRemoteSegmentStore(
         }
         Map<String, RemoteSegmentStoreDirectory.UploadedSegmentMetadata> uploadedSegments = sourceRemoteDirectory
             .getSegmentsUploadedToRemoteStore();
-        final Directory storeDirectory = store.directory();
         store.incRef();
-
         try {
+            final Directory storeDirectory;
+            if (recoveryState.getStage() == RecoveryState.Stage.INDEX) {
+                storeDirectory = new StoreRecovery.StatsDirectoryWrapper(store.directory(), recoveryState.getIndex());
+                for (String file : uploadedSegments.keySet()) {
+                    long checksum = Long.parseLong(uploadedSegments.get(file).getChecksum());
+                    if (overrideLocal || localDirectoryContains(storeDirectory, file, checksum) == false) {
+                        recoveryState.getIndex().addFileDetail(file, uploadedSegments.get(file).getLength(), false);
+                    } else {
+                        recoveryState.getIndex().addFileDetail(file, uploadedSegments.get(file).getLength(), true);
+                    }
+                }
+            } else {
+                storeDirectory = store.directory();
+            }
+
             String segmentsNFile = copySegmentFiles(
                 storeDirectory,
                 sourceRemoteDirectory,

server/src/test/java/org/opensearch/index/shard/IndexShardTests.java

@@ -2896,9 +2896,9 @@ public void testSyncSegmentsFromGivenRemoteSegmentStore() throws IOException {
             RecoverySource.ExistingStoreRecoverySource.INSTANCE
         );
         routing = ShardRoutingHelper.newWithRestoreSource(routing, new RecoverySource.EmptyStoreRecoverySource());
-
         target = reinitShard(target, routing);
-
+        DiscoveryNode localNode = new DiscoveryNode("foo", buildNewFakeTransportAddress(), emptyMap(), emptySet(), Version.CURRENT);
+        target.markAsRecovering("from snapshot", new RecoveryState(routing, localNode, null));
         target.syncSegmentsFromGivenRemoteSegmentStore(false, tempRemoteSegmentDirectory, primaryTerm, commitGeneration);
         RemoteSegmentStoreDirectory remoteStoreDirectory = ((RemoteSegmentStoreDirectory) ((FilterDirectory) ((FilterDirectory) target
             .remoteStore()