Implementation of RemoteWritableEntity for objects to uploaded to remote store

server/src/main/java/org/opensearch/common/remote/RemoteWritableEntityStore.java

@@ -8,6 +8,7 @@
 
 package org.opensearch.common.remote;
 
+import org.opensearch.common.annotation.ExperimentalApi;
 import org.opensearch.core.action.ActionListener;
 
 import java.io.IOException;
@@ -18,6 +19,7 @@
  * @param <T> The object type which can be uploaded to or downloaded from remote storage.
  * @param <U> The wrapper entity which provides methods for serializing/deserializing entity T.
  */
+@ExperimentalApi
 public interface RemoteWritableEntityStore<T, U extends RemoteWriteableEntity<T>> {
 
     public void writeAsync(U entity, ActionListener<Void> listener);

server/src/main/java/org/opensearch/common/remote/RemoteWriteableEntity.java

@@ -8,6 +8,8 @@
 
 package org.opensearch.common.remote;
 
+import org.opensearch.common.annotation.ExperimentalApi;
+
 import java.io.IOException;
 import java.io.InputStream;
 
@@ -17,6 +19,7 @@
  *
  * @param <T> The object type which can be uploaded to or downloaded from remote storage.
  */
+@ExperimentalApi
 public interface RemoteWriteableEntity<T> {
     /**
      * @return An InputStream created by serializing the entity T

server/src/main/java/org/opensearch/gateway/remote/RemoteClusterStateUtils.java

@@ -8,14 +8,30 @@
 
 package org.opensearch.gateway.remote;
 
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.core.xcontent.ToXContent;
+
 import java.nio.charset.StandardCharsets;
 import java.util.Base64;
+import java.util.Map;
 
 /**
  * Utility class for Remote Cluster State
  */
 public class RemoteClusterStateUtils {
+
+    public static final String DELIMITER = "__";
     public static final String PATH_DELIMITER = "/";
+    public static final String GLOBAL_METADATA_PATH_TOKEN = "global-metadata";
+    public static final String METADATA_NAME_FORMAT = "%s.dat";
+    public static final String METADATA_NAME_PLAIN_FORMAT = "%s";
+    public static final int GLOBAL_METADATA_CURRENT_CODEC_VERSION = 1;
+
+    // ToXContent Params with gateway mode.
+    // We are using gateway context mode to persist all custom metadata.
+    public static final ToXContent.Params FORMAT_PARAMS = new ToXContent.MapParams(
+        Map.of(Metadata.CONTEXT_MODE_PARAM, Metadata.CONTEXT_MODE_GATEWAY)
+    );
 
     public static String encodeString(String content) {
         return Base64.getUrlEncoder().withoutPadding().encodeToString(content.getBytes(StandardCharsets.UTF_8));

server/src/main/java/org/opensearch/gateway/remote/model/RemoteClusterMetadataManifest.java

@@ -0,0 +1,153 @@
+/*
+ * 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.gateway.remote.model;
+
+import org.opensearch.common.io.Streams;
+import org.opensearch.common.remote.AbstractRemoteWritableBlobEntity;
+import org.opensearch.common.remote.BlobPathParameters;
+import org.opensearch.core.compress.Compressor;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.gateway.remote.ClusterMetadataManifest;
+import org.opensearch.gateway.remote.ClusterMetadataManifest.UploadedMetadata;
+import org.opensearch.gateway.remote.ClusterMetadataManifest.UploadedMetadataAttribute;
+import org.opensearch.gateway.remote.RemoteClusterStateUtils;
+import org.opensearch.index.remote.RemoteStoreUtils;
+import org.opensearch.repositories.blobstore.ChecksumBlobStoreFormat;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.List;
+
+import static org.opensearch.gateway.remote.RemoteClusterStateUtils.DELIMITER;
+
+/**
+ * Wrapper class for uploading/downloading {@link ClusterMetadataManifest} to/from remote blob store
+ */
+public class RemoteClusterMetadataManifest extends AbstractRemoteWritableBlobEntity<ClusterMetadataManifest> {
+
+    public static final String MANIFEST = "manifest";
+    public static final int SPLITTED_MANIFEST_FILE_LENGTH = 6;
+
+    public static final String METADATA_MANIFEST_NAME_FORMAT = "%s";
+    public static final int MANIFEST_CURRENT_CODEC_VERSION = ClusterMetadataManifest.CODEC_V3;
+    public static final String COMMITTED = "C";
+    public static final String PUBLISHED = "P";
+
+    /**
+     * Manifest format compatible with older codec v0, where codec version was missing.
+     */
+    public static final ChecksumBlobStoreFormat<ClusterMetadataManifest> CLUSTER_METADATA_MANIFEST_FORMAT_V0 =
+        new ChecksumBlobStoreFormat<>("cluster-metadata-manifest", METADATA_MANIFEST_NAME_FORMAT, ClusterMetadataManifest::fromXContentV0);
+    /**
+     * Manifest format compatible with older codec v1, where global metadata was missing.
+     */
+    public static final ChecksumBlobStoreFormat<ClusterMetadataManifest> CLUSTER_METADATA_MANIFEST_FORMAT_V1 =
+        new ChecksumBlobStoreFormat<>("cluster-metadata-manifest", METADATA_MANIFEST_NAME_FORMAT, ClusterMetadataManifest::fromXContentV1);
+
+    /**
+     * Manifest format compatible with codec v2, where we introduced codec versions/global metadata.
+     */
+    public static final ChecksumBlobStoreFormat<ClusterMetadataManifest> CLUSTER_METADATA_MANIFEST_FORMAT = new ChecksumBlobStoreFormat<>(
+        "cluster-metadata-manifest",
+        METADATA_MANIFEST_NAME_FORMAT,
+        ClusterMetadataManifest::fromXContent
+    );
+
+    private ClusterMetadataManifest clusterMetadataManifest;
+
+    public RemoteClusterMetadataManifest(
+        final ClusterMetadataManifest clusterMetadataManifest,
+        final String clusterUUID,
+        final Compressor compressor,
+        final NamedXContentRegistry namedXContentRegistry
+    ) {
+        super(clusterUUID, compressor, namedXContentRegistry);
+        this.clusterMetadataManifest = clusterMetadataManifest;
+    }
+
+    public RemoteClusterMetadataManifest(
+        final String blobName,
+        final String clusterUUID,
+        final Compressor compressor,
+        final NamedXContentRegistry namedXContentRegistry
+    ) {
+        super(clusterUUID, compressor, namedXContentRegistry);
+        this.blobName = blobName;
+    }
+
+    @Override
+    public BlobPathParameters getBlobPathParameters() {
+        return new BlobPathParameters(List.of(MANIFEST), MANIFEST);
+    }
+
+    @Override
+    public String generateBlobFileName() {
+        // 123456789012_test-cluster/cluster-state/dsgYj10Nkso7/manifest/manifest__<inverted_term>__<inverted_version>__C/P__<inverted__timestamp>__
+        // <codec_version>
+        String blobFileName = String.join(
+            DELIMITER,
+            MANIFEST,
+            RemoteStoreUtils.invertLong(clusterMetadataManifest.getClusterTerm()),
+            RemoteStoreUtils.invertLong(clusterMetadataManifest.getStateVersion()),
+            (clusterMetadataManifest.isCommitted() ? COMMITTED : PUBLISHED),
+            RemoteStoreUtils.invertLong(System.currentTimeMillis()),
+            String.valueOf(clusterMetadataManifest.getCodecVersion())
+            // Keep the codec version at last place only, during we read last place to determine codec version.
+        );
+        this.blobFileName = blobFileName;
+        return blobFileName;
+    }
+
+    @Override
+    public UploadedMetadata getUploadedMetadata() {
+        assert blobName != null;
+        return new UploadedMetadataAttribute(MANIFEST, blobName);
+    }
+
+    @Override
+    public InputStream serialize() throws IOException {
+        return CLUSTER_METADATA_MANIFEST_FORMAT.serialize(
+            clusterMetadataManifest,
+            generateBlobFileName(),
+            getCompressor(),
+            RemoteClusterStateUtils.FORMAT_PARAMS
+        ).streamInput();
+    }
+
+    @Override
+    public ClusterMetadataManifest deserialize(final InputStream inputStream) throws IOException {
+        ChecksumBlobStoreFormat<ClusterMetadataManifest> blobStoreFormat = getClusterMetadataManifestBlobStoreFormat();
+        return blobStoreFormat.deserialize(blobName, getNamedXContentRegistry(), Streams.readFully(inputStream));
+    }
+
+    private int getManifestCodecVersion() {
+        assert blobName != null;
+        String[] splitName = blobName.split(DELIMITER);
+        if (splitName.length == SPLITTED_MANIFEST_FILE_LENGTH) {
+            return Integer.parseInt(splitName[splitName.length - 1]); // Last value would be codec version.
+        } else if (splitName.length < SPLITTED_MANIFEST_FILE_LENGTH) { // Where codec is not part of file name, i.e. default codec version 0
+            // is used.
+            return ClusterMetadataManifest.CODEC_V0;
+        } else {
+            throw new IllegalArgumentException("Manifest file name is corrupted");
+        }
+    }
+
+    private ChecksumBlobStoreFormat<ClusterMetadataManifest> getClusterMetadataManifestBlobStoreFormat() {
+        long codecVersion = getManifestCodecVersion();
+        if (codecVersion == MANIFEST_CURRENT_CODEC_VERSION) {
+            return CLUSTER_METADATA_MANIFEST_FORMAT;
+        } else if (codecVersion == ClusterMetadataManifest.CODEC_V1) {
+            return CLUSTER_METADATA_MANIFEST_FORMAT_V1;
+        } else if (codecVersion == ClusterMetadataManifest.CODEC_V0) {
+            return CLUSTER_METADATA_MANIFEST_FORMAT_V0;
+        }
+        throw new IllegalArgumentException("Cluster metadata manifest file is corrupted, don't have valid codec version");
+    }
+}

server/src/main/java/org/opensearch/gateway/remote/model/RemoteCoordinationMetadata.java

@@ -0,0 +1,107 @@
+/*
+ * 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.gateway.remote.model;
+
+import org.opensearch.cluster.coordination.CoordinationMetadata;
+import org.opensearch.common.io.Streams;
+import org.opensearch.common.remote.AbstractRemoteWritableBlobEntity;
+import org.opensearch.common.remote.BlobPathParameters;
+import org.opensearch.core.compress.Compressor;
+import org.opensearch.core.xcontent.NamedXContentRegistry;
+import org.opensearch.gateway.remote.ClusterMetadataManifest.UploadedMetadata;
+import org.opensearch.gateway.remote.ClusterMetadataManifest.UploadedMetadataAttribute;
+import org.opensearch.gateway.remote.RemoteClusterStateUtils;
+import org.opensearch.index.remote.RemoteStoreUtils;
+import org.opensearch.repositories.blobstore.ChecksumBlobStoreFormat;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.List;
+
+import static org.opensearch.gateway.remote.RemoteClusterStateUtils.DELIMITER;
+import static org.opensearch.gateway.remote.RemoteClusterStateUtils.GLOBAL_METADATA_CURRENT_CODEC_VERSION;
+import static org.opensearch.gateway.remote.RemoteClusterStateUtils.METADATA_NAME_PLAIN_FORMAT;
+
+/**
+ * Wrapper class for uploading/downloading {@link CoordinationMetadata} to/from remote blob store
+ */
+public class RemoteCoordinationMetadata extends AbstractRemoteWritableBlobEntity<CoordinationMetadata> {
+
+    public static final String COORDINATION_METADATA = "coordination";
+    public static final ChecksumBlobStoreFormat<CoordinationMetadata> COORDINATION_METADATA_FORMAT = new ChecksumBlobStoreFormat<>(
+        "coordination",
+        METADATA_NAME_PLAIN_FORMAT,
+        CoordinationMetadata::fromXContent
+    );
+
+    private CoordinationMetadata coordinationMetadata;
+    private long metadataVersion;
+
+    public RemoteCoordinationMetadata(
+        final CoordinationMetadata coordinationMetadata,
+        final long metadataVersion,
+        final String clusterUUID,
+        final Compressor compressor,
+        final NamedXContentRegistry namedXContentRegistry
+    ) {
+        super(clusterUUID, compressor, namedXContentRegistry);
+        this.coordinationMetadata = coordinationMetadata;
+        this.metadataVersion = metadataVersion;
+    }
+
+    public RemoteCoordinationMetadata(
+        final String blobName,
+        final String clusterUUID,
+        final Compressor compressor,
+        final NamedXContentRegistry namedXContentRegistry
+    ) {
+        super(clusterUUID, compressor, namedXContentRegistry);
+        this.blobName = blobName;
+    }
+
+    @Override
+    public BlobPathParameters getBlobPathParameters() {
+        return new BlobPathParameters(List.of("global-metadata"), COORDINATION_METADATA);
+    }
+
+    @Override
+    public String generateBlobFileName() {
+        // 123456789012_test-cluster/cluster-state/dsgYj10Nkso7/global-metadata/<componentPrefix>__<inverted_metadata_version>__<inverted__timestamp>__<codec_version>
+        String blobFileName = String.join(
+            DELIMITER,
+            getBlobPathParameters().getFilePrefix(),
+            RemoteStoreUtils.invertLong(metadataVersion),
+            RemoteStoreUtils.invertLong(System.currentTimeMillis()),
+            String.valueOf(GLOBAL_METADATA_CURRENT_CODEC_VERSION)
+        );
+        this.blobFileName = blobFileName;
+        return blobFileName;
+    }
+
+    @Override
+    public InputStream serialize() throws IOException {
+        return COORDINATION_METADATA_FORMAT.serialize(
+            coordinationMetadata,
+            generateBlobFileName(),
+            getCompressor(),
+            RemoteClusterStateUtils.FORMAT_PARAMS
+        ).streamInput();
+    }
+
+    @Override
+    public CoordinationMetadata deserialize(final InputStream inputStream) throws IOException {
+        return COORDINATION_METADATA_FORMAT.deserialize(blobName, getNamedXContentRegistry(), Streams.readFully(inputStream));
+    }
+
+    @Override
+    public UploadedMetadata getUploadedMetadata() {
+        assert blobName != null;
+        return new UploadedMetadataAttribute(COORDINATION_METADATA, blobName);
+    }
+}