Add path prefix support to hashed prefix snapshots (#15664)

* Add path prefix support to hashed prefix snapshots

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

* Fix test

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

---------

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

CHANGELOG.md

@@ -47,6 +47,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - [Remote Publication] Add remote download stats ([#15291](https://github.com/opensearch-project/OpenSearch/pull/15291)))
 - Add support for comma-separated list of index names to be used with Snapshot Status API ([#15409](https://github.com/opensearch-project/OpenSearch/pull/15409))
 - Add prefix support to hashed prefix & infix path types on remote store ([#15557](https://github.com/opensearch-project/OpenSearch/pull/15557))
+- Add path prefix support to hashed prefix snapshots ([#15664](https://github.com/opensearch-project/OpenSearch/pull/15664))
 - Optimise snapshot deletion to speed up snapshot deletion and creation ([#15568](https://github.com/opensearch-project/OpenSearch/pull/15568))
 - [Remote Publication] Added checksum validation for cluster state behind a cluster setting ([#15218](https://github.com/opensearch-project/OpenSearch/pull/15218))
 - Add canRemain method to TargetPoolAllocationDecider to move shards from local to remote pool for hot to warm tiering ([#15010](https://github.com/opensearch-project/OpenSearch/pull/15010))

server/src/main/java/org/opensearch/common/settings/ClusterSettings.java

@@ -152,6 +152,7 @@
 import org.opensearch.ratelimitting.admissioncontrol.AdmissionControlSettings;
 import org.opensearch.ratelimitting.admissioncontrol.settings.CpuBasedAdmissionControllerSettings;
 import org.opensearch.ratelimitting.admissioncontrol.settings.IoBasedAdmissionControllerSettings;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
 import org.opensearch.repositories.fs.FsRepository;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.script.ScriptService;
@@ -777,6 +778,7 @@ public void apply(Settings value, Settings current, Settings previous) {
                 RemoteStoreSettings.CLUSTER_REMOTE_STORE_PINNED_TIMESTAMP_ENABLED,
                 RemoteStoreSettings.CLUSTER_REMOTE_STORE_SEGMENTS_PATH_PREFIX,
                 RemoteStoreSettings.CLUSTER_REMOTE_STORE_TRANSLOG_PATH_PREFIX,
+                BlobStoreRepository.SNAPSHOT_SHARD_PATH_PREFIX_SETTING,
 
                 SearchService.CLUSTER_ALLOW_DERIVED_FIELD_SETTING,
 

server/src/main/java/org/opensearch/repositories/blobstore/BlobStoreRepository.java

@@ -343,6 +343,16 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
         Setting.Property.NodeScope
     );
 
+    /**
+     * Controls the fixed prefix for the snapshot shard blob path.
+     */
+    public static final Setting<String> SNAPSHOT_SHARD_PATH_PREFIX_SETTING = Setting.simpleString(
+        "cluster.snapshot.shard.path.prefix",
+        "",
+        Setting.Property.NodeScope,
+        Setting.Property.Final
+    );
+
     protected volatile boolean supportURLRepo;
 
     private volatile int maxShardBlobDeleteBatch;
@@ -434,6 +444,8 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
 
     private final NamedXContentRegistry namedXContentRegistry;
 
+    private final String snapshotShardPathPrefix;
+
     /**
      * Flag that is set to {@code true} if this instance is started with {@link #metadata} that has a higher value for
      * {@link RepositoryMetadata#pendingGeneration()} than for {@link RepositoryMetadata#generation()} indicating a full cluster restart
@@ -485,6 +497,7 @@ protected BlobStoreRepository(
         this.clusterService = clusterService;
         this.recoverySettings = recoverySettings;
         this.remoteStoreSettings = new RemoteStoreSettings(clusterService.getSettings(), clusterService.getClusterSettings());
+        this.snapshotShardPathPrefix = SNAPSHOT_SHARD_PATH_PREFIX_SETTING.get(clusterService.getSettings());
     }
 
     @Override
@@ -2729,6 +2742,7 @@ private BlobPath shardPath(IndexId indexId, int shardId) {
         SnapshotShardPathInput shardPathInput = new SnapshotShardPathInput.Builder().basePath(basePath())
             .indexUUID(indexId.getId())
             .shardId(String.valueOf(shardId))
+            .fixedPrefix(snapshotShardPathPrefix)
             .build();
         PathHashAlgorithm pathHashAlgorithm = pathType != PathType.FIXED ? FNV_1A_COMPOSITE_1 : null;
         return pathType.path(shardPathInput, pathHashAlgorithm);

test/framework/src/main/java/org/opensearch/test/OpenSearchIntegTestCase.java

@@ -403,6 +403,8 @@ public abstract class OpenSearchIntegTestCase extends OpenSearchTestCase {
 
     private static Boolean segmentsPathFixedPrefix;
 
+    private static Boolean snapshotShardPathFixedPrefix;
+
     private Path remoteStoreRepositoryPath;
 
     private ReplicationType randomReplicationType;
@@ -414,6 +416,7 @@ public static void beforeClass() throws Exception {
         prefixModeVerificationEnable = randomBoolean();
         translogPathFixedPrefix = randomBoolean();
         segmentsPathFixedPrefix = randomBoolean();
+        snapshotShardPathFixedPrefix = randomBoolean();
         testClusterRule.beforeClass();
     }
 
@@ -2901,6 +2904,7 @@ private static Settings buildRemoteStoreNodeAttributes(
         settings.put(RemoteStoreSettings.CLUSTER_REMOTE_STORE_PINNED_TIMESTAMP_ENABLED.getKey(), randomBoolean());
         settings.put(RemoteStoreSettings.CLUSTER_REMOTE_STORE_SEGMENTS_PATH_PREFIX.getKey(), translogPathFixedPrefix ? "a" : "");
         settings.put(RemoteStoreSettings.CLUSTER_REMOTE_STORE_TRANSLOG_PATH_PREFIX.getKey(), segmentsPathFixedPrefix ? "b" : "");
+        settings.put(BlobStoreRepository.SNAPSHOT_SHARD_PATH_PREFIX_SETTING.getKey(), segmentsPathFixedPrefix ? "c" : "");
         return settings.build();
     }