Introduce interface changes to read/write blob with object metadata

Signed-off-by: Sandeep Kumawat <skumwt@amazon.com>

Author: Sandeep Kumawat

server/src/main/java/org/opensearch/common/blobstore/BlobContainer.java

@@ -77,6 +77,19 @@ public interface BlobContainer {
      */
     InputStream readBlob(String blobName) throws IOException;
 
+    /**
+     * Creates a new {@link BlobDownloadResponse} for the given blob name.
+     *
+     * @param   blobName
+     *          The name of the blob to get an {@link InputStream} for.
+     * @return  The {@code InputStream} to read the blob.
+     * @throws  NoSuchFileException if the blob does not exist
+     * @throws  IOException if the blob can not be read.
+     */
+    default BlobDownloadResponse readBlobWithMetadata(String blobName) throws IOException {
+        return null;
+    };
+
     /**
      * Creates a new {@link InputStream} that can be used to read the given blob starting from
      * a specific {@code position} in the blob. The {@code length} is an indication of the
@@ -128,6 +141,33 @@ default long readBlobPreferredLength() {
      */
     void writeBlob(String blobName, InputStream inputStream, long blobSize, boolean failIfAlreadyExists) throws IOException;
 
+    /**
+     * Reads blob content from the input stream and writes it to the container in a new blob with the given name, and metadata.
+     * This method assumes the container does not already contain a blob of the same blobName.  If a blob by the
+     * same name already exists, the operation will fail and an {@link IOException} will be thrown.
+     *
+     * @param   blobName
+     *          The name of the blob to write the contents of the input stream to.
+     * @param   inputStream
+     *          The input stream from which to retrieve the bytes to write to the blob.
+     * @param   metadata
+     *          The metadata to be associate with the blob upload.
+     * @param   blobSize
+     *          The size of the blob to be written, in bytes.  It is implementation dependent whether
+     *          this value is used in writing the blob to the repository.
+     * @param   failIfAlreadyExists
+     *          whether to throw a FileAlreadyExistsException if the given blob already exists
+     * @throws  FileAlreadyExistsException if failIfAlreadyExists is true and a blob by the same name already exists
+     * @throws  IOException if the input stream could not be read, or the target blob could not be written to.
+     */
+    default void writeBlobWithMetadata(
+        String blobName,
+        InputStream inputStream,
+        Map<String, String> metadata,
+        long blobSize,
+        boolean failIfAlreadyExists
+    ) throws IOException {};
+
     /**
      * Reads blob content from the input stream and writes it to the container in a new blob with the given name,
      * using an atomic write operation if the implementation supports it.
@@ -149,6 +189,35 @@ default long readBlobPreferredLength() {
      */
     void writeBlobAtomic(String blobName, InputStream inputStream, long blobSize, boolean failIfAlreadyExists) throws IOException;
 
+    /**
+     * Reads blob content from the input stream and writes it to the container in a new blob with the given name,and metadata
+     * using an atomic write operation if the implementation supports it.
+     * <p>
+     * This method assumes the container does not already contain a blob of the same blobName.  If a blob by the
+     * same name already exists, the operation will fail and an {@link IOException} will be thrown.
+     *
+     * @param   blobName
+     *          The name of the blob to write the contents of the input stream to.
+     * @param   inputStream
+     *          The input stream from which to retrieve the bytes to write to the blob.
+     * @param   metadata
+     *          The metadata to be associate with the blob upload.
+     * @param   blobSize
+     *          The size of the blob to be written, in bytes.  It is implementation dependent whether
+     *          this value is used in writing the blob to the repository.
+     * @param   failIfAlreadyExists
+     *          whether to throw a FileAlreadyExistsException if the given blob already exists
+     * @throws  FileAlreadyExistsException if failIfAlreadyExists is true and a blob by the same name already exists
+     * @throws  IOException if the input stream could not be read, or the target blob could not be written to.
+     */
+    default void writeBlobAtomicWithMetadata(
+        String blobName,
+        InputStream inputStream,
+        Map<String, String> metadata,
+        long blobSize,
+        boolean failIfAlreadyExists
+    ) throws IOException {};
+
     /**
      * Deletes this container and all its contents from the repository.
      *

server/src/main/java/org/opensearch/common/blobstore/BlobDownloadResponse.java

@@ -0,0 +1,44 @@
+/*
+ * 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.common.blobstore;
+
+import java.io.InputStream;
+import java.util.Map;
+
+/**
+ * A class for blob download response
+ *
+ * @opensearch.internal
+ */
+public class BlobDownloadResponse {
+
+    /**
+     * Downloaded blob InputStream
+     */
+    private InputStream inputStream;
+
+    /**
+     * Metadata of the downloaded blob
+     */
+    private Map<String, String> metadata;
+
+    public InputStream getInputStream() {
+        return inputStream;
+    }
+
+    public Map<String, String> getMetadata() {
+        return metadata;
+    }
+
+    public BlobDownloadResponse(InputStream inputStream, Map<String, String> metadata) {
+        this.inputStream = inputStream;
+        this.metadata = metadata;
+    }
+
+}

server/src/main/java/org/opensearch/index/translog/transfer/BlobStoreTransferService.java

@@ -14,6 +14,7 @@
 import org.opensearch.action.ActionRunnable;
 import org.opensearch.common.blobstore.AsyncMultiStreamBlobContainer;
 import org.opensearch.common.blobstore.BlobContainer;
+import org.opensearch.common.blobstore.BlobDownloadResponse;
 import org.opensearch.common.blobstore.BlobMetadata;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.blobstore.BlobStore;
@@ -164,6 +165,11 @@ public InputStream downloadBlob(Iterable<String> path, String fileName) throws I
         return blobStore.blobContainer((BlobPath) path).readBlob(fileName);
     }
 
+    @Override
+    public BlobDownloadResponse downloadBlobWithMetadata(Iterable<String> path, String fileName) throws IOException {
+        return blobStore.blobContainer((BlobPath) path).readBlobWithMetadata(fileName);
+    }
+
     @Override
     public void deleteBlobs(Iterable<String> path, List<String> fileNames) throws IOException {
         blobStore.blobContainer((BlobPath) path).deleteBlobsIgnoringIfNotExists(fileNames);

server/src/main/java/org/opensearch/index/translog/transfer/TransferService.java

@@ -8,6 +8,7 @@
 
 package org.opensearch.index.translog.transfer;
 
+import org.opensearch.common.blobstore.BlobDownloadResponse;
 import org.opensearch.common.blobstore.BlobMetadata;
 import org.opensearch.common.blobstore.BlobPath;
 import org.opensearch.common.blobstore.stream.write.WritePriority;
@@ -125,6 +126,15 @@ void uploadBlobs(
      */
     InputStream downloadBlob(Iterable<String> path, String fileName) throws IOException;
 
+    /**
+     *
+     * @param path  the remote path from where download should be made
+     * @param fileName the name of the file
+     * @return {@link BlobDownloadResponse} of the remote file
+     * @throws IOException the exception while reading the data
+     */
+    BlobDownloadResponse downloadBlobWithMetadata(Iterable<String> path, String fileName) throws IOException;
+
     void listAllInSortedOrder(Iterable<String> path, String filenamePrefix, int limit, ActionListener<List<BlobMetadata>> listener);
 
     void listAllInSortedOrderAsync(