Add snapshot shard blobs with hashed prefix

Signed-off-by: Ashish Singh <ssashish@amazon.com>

server/src/main/java/org/opensearch/index/recovery/RemoteStoreRestoreService.java

@@ -227,7 +227,8 @@ private RemoteRestoreResult executeRestore(
                     .build();
             }
 
-            IndexId indexId = new IndexId(indexName, updatedIndexMetadata.getIndexUUID());
+            // This instance of IndexId is not related to Snapshot Restore. Hence, we are using the ctor without pathType.
+            IndexId indexId = new IndexId(indexName, updatedIndexMetadata.getIndexUUID(), IndexId.DEFAULT_SHARD_PATH_TYPE);
 
             if (metadataFromRemoteStore == false) {
                 Map<ShardId, IndexShardRoutingTable> indexShardRoutingTableMap = currentState.routingTable()

server/src/main/java/org/opensearch/index/remote/RemoteIndexPathUploader.java

@@ -64,7 +64,8 @@ public class RemoteIndexPathUploader extends IndexMetadataUploadListener {
 
     public static final String DELIMITER = "#";
     public static final ConfigBlobStoreFormat<RemoteIndexPath> REMOTE_INDEX_PATH_FORMAT = new ConfigBlobStoreFormat<>(
-        RemoteIndexPath.FILE_NAME_FORMAT
+        RemoteIndexPath.FILE_NAME_FORMAT,
+        RemoteIndexPath::fromXContent
     );
 
     private static final String TIMEOUT_EXCEPTION_MSG = "Timed out waiting while uploading remote index path file for indexes=%s";

server/src/main/java/org/opensearch/index/remote/RemoteStoreEnums.java

@@ -207,7 +207,7 @@ public enum PathHashAlgorithm {
             @Override
             String hash(PathInput pathInput) {
                 StringBuilder input = new StringBuilder();
-                for (String path : pathInput.fixedSubPath().toArray()) {
+                for (String path : pathInput.hashPath().toArray()) {
                     input.append(path);
                 }
                 long hash = FNV1a.hash64(input.toString());
@@ -222,7 +222,7 @@ String hash(PathInput pathInput) {
             @Override
             String hash(PathInput pathInput) {
                 StringBuilder input = new StringBuilder();
-                for (String path : pathInput.fixedSubPath().toArray()) {
+                for (String path : pathInput.hashPath().toArray()) {
                     input.append(path);
                 }
                 long hash = FNV1a.hash64(input.toString());

server/src/main/java/org/opensearch/index/remote/RemoteStorePathStrategy.java

@@ -17,6 +17,7 @@
 import org.opensearch.index.remote.RemoteStoreEnums.DataType;
 import org.opensearch.index.remote.RemoteStoreEnums.PathHashAlgorithm;
 import org.opensearch.index.remote.RemoteStoreEnums.PathType;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
 
 import java.util.Objects;
 
@@ -100,6 +101,10 @@ BlobPath fixedSubPath() {
             return BlobPath.cleanPath().add(indexUUID);
         }
 
+        BlobPath hashPath() {
+            return BlobPath.cleanPath().add(indexUUID);
+        }
+
         /**
          * Returns a new builder for {@link PathInput}.
          */
@@ -127,7 +132,7 @@ public T basePath(BlobPath basePath) {
                 return self();
             }
 
-            public Builder indexUUID(String indexUUID) {
+            public T indexUUID(String indexUUID) {
                 this.indexUUID = indexUUID;
                 return self();
             }
@@ -142,6 +147,61 @@ public PathInput build() {
         }
     }
 
+    /**
+     * A subclass of {@link PathInput} that represents the input required to generate a path
+     * for a shard in a snapshot. It includes the base path, index UUID, and shard ID.
+     *
+     * @opensearch.internal
+     */
+    public static class SnapshotShardPathInput extends PathInput {
+        private final String shardId;
+
+        public SnapshotShardPathInput(SnapshotShardPathInput.Builder builder) {
+            super(builder);
+            this.shardId = Objects.requireNonNull(builder.shardId);
+        }
+
+        @Override
+        BlobPath fixedSubPath() {
+            return BlobPath.cleanPath().add(BlobStoreRepository.INDICES_DIR).add(super.fixedSubPath()).add(shardId);
+        }
+
+        @Override
+        BlobPath hashPath() {
+            return BlobPath.cleanPath().add(shardId).add(indexUUID());
+        }
+
+        /**
+         * Returns a new builder for {@link SnapshotShardPathInput}.
+         */
+        public static SnapshotShardPathInput.Builder builder() {
+            return new SnapshotShardPathInput.Builder();
+        }
+
+        /**
+         * Builder for {@link SnapshotShardPathInput}.
+         *
+         * @opensearch.internal
+         */
+        public static class Builder extends PathInput.Builder<SnapshotShardPathInput.Builder> {
+            private String shardId;
+
+            public SnapshotShardPathInput.Builder shardId(String shardId) {
+                this.shardId = shardId;
+                return this;
+            }
+
+            @Override
+            protected SnapshotShardPathInput.Builder self() {
+                return this;
+            }
+
+            public SnapshotShardPathInput build() {
+                return new SnapshotShardPathInput(this);
+            }
+        }
+    }
+
     /**
      * Wrapper class for the data aware path input required to generate path for remote store uploads. This input is
      * composed of the parent inputs, shard id, data category and data type.
@@ -204,16 +264,6 @@ public static class Builder extends PathInput.Builder<Builder> {
             private DataCategory dataCategory;
             private DataType dataType;
 
-            public Builder basePath(BlobPath basePath) {
-                super.basePath = basePath;
-                return this;
-            }
-
-            public Builder indexUUID(String indexUUID) {
-                super.indexUUID = indexUUID;
-                return this;
-            }
-
             public Builder shardId(String shardId) {
                 this.shardId = shardId;
                 return this;

server/src/main/java/org/opensearch/repositories/IndexId.java

@@ -32,6 +32,7 @@
 
 package org.opensearch.repositories;
 
+import org.opensearch.Version;
 import org.opensearch.common.annotation.PublicApi;
 import org.opensearch.core.common.io.stream.StreamInput;
 import org.opensearch.core.common.io.stream.StreamOutput;
@@ -40,6 +41,7 @@
 import org.opensearch.core.xcontent.ToXContent;
 import org.opensearch.core.xcontent.ToXContentObject;
 import org.opensearch.core.xcontent.XContentBuilder;
+import org.opensearch.index.remote.RemoteStoreEnums;
 
 import java.io.IOException;
 import java.util.Objects;
@@ -51,23 +53,36 @@
  */
 @PublicApi(since = "1.0.0")
 public final class IndexId implements Writeable, ToXContentObject {
-    protected static final String NAME = "name";
-    protected static final String ID = "id";
+    static final String NAME = "name";
+    static final String ID = "id";
+    static final String SHARD_PATH_TYPE = "shard_path_type";
+    public static final int DEFAULT_SHARD_PATH_TYPE = RemoteStoreEnums.PathType.FIXED.getCode();
 
     private final String name;
     private final String id;
+    private final int shardPathType;
     private final int hashCode;
 
+    // Used for testing only
     public IndexId(final String name, final String id) {
+        this(name, id, DEFAULT_SHARD_PATH_TYPE);
+    }
+
+    public IndexId(String name, String id, int shardPathType) {
         this.name = name;
         this.id = id;
+        this.shardPathType = shardPathType;
         this.hashCode = computeHashCode();
-
     }
 
     public IndexId(final StreamInput in) throws IOException {
         this.name = in.readString();
         this.id = in.readString();
+        if (in.getVersion().onOrAfter(Version.CURRENT)) {
+            this.shardPathType = in.readVInt();
+        } else {
+            this.shardPathType = DEFAULT_SHARD_PATH_TYPE;
+        }
         this.hashCode = computeHashCode();
     }
 
@@ -93,9 +108,16 @@ public String getId() {
         return id;
     }
 
+    /**
+     * The storage path type in remote store for the indexes having the underlying index ids.
+     */
+    public int getShardPathType() {
+        return shardPathType;
+    }
+
     @Override
     public String toString() {
-        return "[" + name + "/" + id + "]";
+        return "[" + name + "/" + id + "/" + shardPathType + "]";
     }
 
     @Override
@@ -107,7 +129,7 @@ public boolean equals(Object o) {
             return false;
         }
         IndexId that = (IndexId) o;
-        return Objects.equals(name, that.name) && Objects.equals(id, that.id);
+        return Objects.equals(name, that.name) && Objects.equals(id, that.id) && Objects.equals(this.shardPathType, that.shardPathType);
     }
 
     @Override
@@ -116,20 +138,24 @@ public int hashCode() {
     }
 
     private int computeHashCode() {
-        return Objects.hash(name, id);
+        return Objects.hash(name, id, shardPathType);
     }
 
     @Override
     public void writeTo(final StreamOutput out) throws IOException {
         out.writeString(name);
         out.writeString(id);
+        if (out.getVersion().onOrAfter(Version.CURRENT)) {
+            out.writeVInt(shardPathType);
+        }
     }
 
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, ToXContent.Params params) throws IOException {
         builder.startObject();
         builder.field(NAME, name);
         builder.field(ID, id);
+        builder.field(SHARD_PATH_TYPE, shardPathType);
         builder.endObject();
         return builder;
     }

server/src/main/java/org/opensearch/repositories/RepositoryData.java

@@ -517,15 +517,15 @@ public List<IndexId> resolveIndices(final List<String> indices) {
      * @param indicesToResolve names of indices to resolve
      * @param inFlightIds      name to index mapping for currently in-flight snapshots not yet in the repository data to fall back to
      */
-    public List<IndexId> resolveNewIndices(List<String> indicesToResolve, Map<String, IndexId> inFlightIds) {
+    public List<IndexId> resolveNewIndices(List<String> indicesToResolve, Map<String, IndexId> inFlightIds, int pathType) {
         List<IndexId> snapshotIndices = new ArrayList<>();
         for (String index : indicesToResolve) {
             IndexId indexId = indices.get(index);
             if (indexId == null) {
                 indexId = inFlightIds.get(index);
             }
             if (indexId == null) {
-                indexId = new IndexId(index, UUIDs.randomBase64UUID());
+                indexId = new IndexId(index, UUIDs.randomBase64UUID(), pathType);
             }
             snapshotIndices.add(indexId);
         }
@@ -544,10 +544,16 @@ public List<IndexId> resolveNewIndices(List<String> indicesToResolve, Map<String
     private static final String VERSION = "version";
     private static final String MIN_VERSION = "min_version";
 
+    // Visible for testing only
+    public XContentBuilder snapshotsToXContent(final XContentBuilder builder, final Version repoMetaVersion) throws IOException {
+        return snapshotsToXContent(builder, repoMetaVersion, Version.CURRENT);
+    }
+
     /**
      * Writes the snapshots metadata and the related indices metadata to x-content.
      */
-    public XContentBuilder snapshotsToXContent(final XContentBuilder builder, final Version repoMetaVersion) throws IOException {
+    public XContentBuilder snapshotsToXContent(final XContentBuilder builder, final Version repoMetaVersion, final Version minNodeVersion)
+        throws IOException {
         builder.startObject();
         // write the snapshots list
         builder.startArray(SNAPSHOTS);
@@ -578,6 +584,9 @@ public XContentBuilder snapshotsToXContent(final XContentBuilder builder, final
         for (final IndexId indexId : getIndices().values()) {
             builder.startObject(indexId.getName());
             builder.field(INDEX_ID, indexId.getId());
+            if (minNodeVersion.onOrAfter(Version.CURRENT)) {
+                builder.field(IndexId.SHARD_PATH_TYPE, indexId.getShardPathType());
+            }
             builder.startArray(SNAPSHOTS);
             List<SnapshotId> snapshotIds = indexSnapshots.get(indexId);
             assert snapshotIds != null;
@@ -765,14 +774,20 @@ private static void parseIndices(
             final List<SnapshotId> snapshotIds = new ArrayList<>();
             final List<String> gens = new ArrayList<>();
 
+            String id = null;
+            int pathType = IndexId.DEFAULT_SHARD_PATH_TYPE;
             IndexId indexId = null;
+
             XContentParserUtils.ensureExpectedToken(XContentParser.Token.START_OBJECT, parser.nextToken(), parser);
             while (parser.nextToken() != XContentParser.Token.END_OBJECT) {
                 final String indexMetaFieldName = parser.currentName();
                 final XContentParser.Token currentToken = parser.nextToken();
                 switch (indexMetaFieldName) {
                     case INDEX_ID:
-                        indexId = new IndexId(indexName, parser.text());
+                        id = parser.text();
+                        break;
+                    case IndexId.SHARD_PATH_TYPE:
+                        pathType = parser.intValue();
                         break;
                     case SNAPSHOTS:
                         XContentParserUtils.ensureExpectedToken(XContentParser.Token.START_ARRAY, currentToken, parser);
@@ -795,7 +810,7 @@ private static void parseIndices(
                                 // different versions create or delete snapshot in the same repository.
                                 throw new OpenSearchParseException(
                                     "Detected a corrupted repository, index "
-                                        + indexId
+                                        + new IndexId(indexName, id, pathType)
                                         + " references an unknown snapshot uuid ["
                                         + uuid
                                         + "]"
@@ -812,9 +827,10 @@ private static void parseIndices(
                         break;
                 }
             }
-            assert indexId != null;
+            assert id != null;
+            indexId = new IndexId(indexName, id, pathType);
             indexSnapshots.put(indexId, Collections.unmodifiableList(snapshotIds));
-            indexLookup.put(indexId.getId(), indexId);
+            indexLookup.put(id, indexId);
             for (int i = 0; i < gens.size(); i++) {
                 String parsedGen = gens.get(i);
                 if (parsedGen != null) {