Add support for CompositeDirectory

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

@@ -87,6 +87,7 @@
 import org.opensearch.index.shard.ShardNotInPrimaryModeException;
 import org.opensearch.index.shard.ShardPath;
 import org.opensearch.index.similarity.SimilarityService;
+import org.opensearch.index.store.CompositeDirectory;
 import org.opensearch.index.store.Store;
 import org.opensearch.index.translog.Translog;
 import org.opensearch.indices.breaker.CircuitBreakerService;
@@ -504,11 +505,11 @@ public synchronized IndexShard createShard(
                 }
             };
             Directory directory = directoryFactory.newDirectory(this.indexSettings, path);
-            Directory remoteDirectory = null;
             if (this.indexSettings.isRemoteStoreEnabled()) {
                 try {
                     Repository repository = repositoriesService.repository("dragon-stone");
-                    remoteDirectory = remoteDirectoryFactory.newDirectory(this.indexSettings, path, repository);
+                    Directory remoteDirectory = remoteDirectoryFactory.newDirectory(this.indexSettings, path, repository);
+                    directory = new CompositeDirectory(directory, remoteDirectory);
                 } catch (RepositoryMissingException e) {
                     throw new IllegalArgumentException(
                         "Repository should be created before creating index with remote_store enabled setting",
@@ -520,7 +521,6 @@ public synchronized IndexShard createShard(
                 shardId,
                 this.indexSettings,
                 directory,
-                remoteDirectory,
                 lock,
                 new StoreCloseListener(shardId, () -> eventListener.onStoreClosed(shardId))
             );

server/src/main/java/org/opensearch/index/store/CompositeDirectory.java

@@ -0,0 +1,52 @@
+/*
+ * 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.store;
+
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.FilterDirectory;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.IndexOutput;
+
+import java.io.IOException;
+import java.util.Set;
+
+public class CompositeDirectory extends FilterDirectory {
+    private final Directory directory1;
+    private final Directory directory2;
+
+    public CompositeDirectory(Directory directory1, Directory directory2) {
+        super(directory1);
+        this.directory1 = directory1;
+        this.directory2 = directory2;
+    }
+
+    @Override
+    public void deleteFile(String name) throws IOException {
+        directory1.deleteFile(name);
+        directory2.deleteFile(name);
+    }
+
+    @Override
+    public IndexOutput createOutput(String name, IOContext context) throws IOException {
+        IndexOutput output1 = directory1.createOutput(name, context);
+        IndexOutput output2 = directory2.createOutput(name, context);
+        return new CompositeIndexOutput(name, name, output1, output2, directory1);
+    }
+
+    @Override
+    public void close() throws IOException {
+        directory1.close();
+        directory2.close();
+    }
+
+    @Override
+    public Set<String> getPendingDeletions() throws IOException {
+        return directory1.getPendingDeletions();
+    }
+}

server/src/main/java/org/opensearch/index/store/CompositeIndexOutput.java

@@ -0,0 +1,56 @@
+/*
+ * 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.store;
+
+import org.apache.lucene.store.Directory;
+import org.apache.lucene.store.IOContext;
+import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.store.IndexOutput;
+
+import java.io.IOException;
+
+public class CompositeIndexOutput extends IndexOutput {
+    private final IndexOutput output1;
+    private final IndexOutput output2;
+    private final Directory directory1;
+
+    protected CompositeIndexOutput(String resourceDescription, String name, IndexOutput output1, IndexOutput output2, Directory directory1) {
+        super(resourceDescription, name);
+        this.output1 = output1;
+        this.output2 = output2;
+        this.directory1 = directory1;
+    }
+
+    @Override
+    public void close() throws IOException {
+        output1.close();
+        IndexInput indexInput = directory1.openInput(this.getName(), IOContext.DEFAULT);
+        output2.copyBytes(indexInput, indexInput.length());
+    }
+
+    @Override
+    public long getFilePointer() {
+        return output1.getFilePointer();
+    }
+
+    @Override
+    public long getChecksum() throws IOException {
+        return output1.getChecksum();
+    }
+
+    @Override
+    public void writeByte(byte b) throws IOException {
+        output1.writeByte(b);
+    }
+
+    @Override
+    public void writeBytes(byte[] b, int offset, int length) throws IOException {
+        output1.writeBytes(b, offset, length);
+    }
+}

server/src/main/java/org/opensearch/index/store/Store.java

@@ -174,7 +174,6 @@ public class Store extends AbstractIndexShardComponent implements Closeable, Ref
 
     private final AtomicBoolean isClosed = new AtomicBoolean(false);
     private final StoreDirectory directory;
-    private final StoreDirectory secondaryDirectory;
     private final ReentrantReadWriteLock metadataLock = new ReentrantReadWriteLock();
     private final ShardLock shardLock;
     private final OnClose onClose;
@@ -188,22 +187,13 @@ protected void closeInternal() {
     };
 
     public Store(ShardId shardId, IndexSettings indexSettings, Directory directory, ShardLock shardLock) {
-        this(shardId, indexSettings, directory, null, shardLock, OnClose.EMPTY);
-    }
-
-    public Store(ShardId shardId, IndexSettings indexSettings, Directory directory, Directory secondaryDirectory, ShardLock shardLock) {
-        this(shardId, indexSettings, directory, secondaryDirectory, shardLock, OnClose.EMPTY);
-    }
-
-    public Store(ShardId shardId, IndexSettings indexSettings, Directory directory, ShardLock shardLock, OnClose onClose) {
-        this(shardId, indexSettings, directory, null, shardLock, onClose);
+        this(shardId, indexSettings, directory, shardLock, OnClose.EMPTY);
     }
 
     public Store(
         ShardId shardId,
         IndexSettings indexSettings,
         Directory directory,
-        Directory secondaryDirectory,
         ShardLock shardLock,
         OnClose onClose
     ) {
@@ -212,12 +202,6 @@ public Store(
         logger.debug("store stats are refreshed with refresh_interval [{}]", refreshInterval);
         ByteSizeCachingDirectory sizeCachingDir = new ByteSizeCachingDirectory(directory, refreshInterval);
         this.directory = new StoreDirectory(sizeCachingDir, Loggers.getLogger("index.store.deletes", shardId));
-        if (secondaryDirectory != null) {
-            ByteSizeCachingDirectory sizeCachingSecondaryDir = new ByteSizeCachingDirectory(secondaryDirectory, refreshInterval);
-            this.secondaryDirectory = new StoreDirectory(sizeCachingSecondaryDir, Loggers.getLogger("index.store.deletes", shardId));
-        } else {
-            this.secondaryDirectory = null;
-        }
         this.shardLock = shardLock;
         this.onClose = onClose;
 
@@ -227,20 +211,7 @@ public Store(
     }
 
     public Directory directory() {
-        return directory(true);
-    }
-
-    public Directory secondaryDirectory() {
-        return directory(false);
-    }
-
-    private Directory directory(boolean primary) {
-        ensureOpen();
-        if (primary) {
-            return directory;
-        } else {
-            return secondaryDirectory;
-        }
+        return directory;
     }
 
     /**