[Searchable Snapshot] Deleted the cache path on index deletion. (#6830)…

… (#6856)

* [SearchableSnapshot] Deleted the cache path on index deletion.



* Added changelog, updated Integ Test.



* Removed changelog entry, updated validation in integ tests.



* Removed unused import statements.



---------



(cherry picked from commit bd9b00d)

Signed-off-by: Harsh Jain <harshjai@amazon.com>
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Harsh Jain <harshjai@amazon.com>

server/src/internalClusterTest/java/org/opensearch/snapshots/SearchableSnapshotIT.java

@@ -35,14 +35,10 @@
 import org.opensearch.monitor.fs.FsInfo;
 import org.opensearch.repositories.fs.FsRepository;
 
-import java.io.IOException;
 import java.nio.file.Files;
-import java.nio.file.NoSuchFileException;
 import java.nio.file.Path;
-import java.nio.file.StandardCopyOption;
 import java.util.List;
 import java.util.Map;
-import java.util.stream.Stream;
 
 import static org.hamcrest.Matchers.contains;
 import static org.hamcrest.Matchers.equalTo;
@@ -559,22 +555,15 @@ public void testCacheFilesAreClosedAfterUse() throws Exception {
         // The local cache files should be closed by deleting the restored index
         deleteIndicesAndEnsureGreen(client, restoredIndexName);
 
-        logger.info("--> validate all the cache files are closed");
+        logger.info("--> validate cache file path is deleted");
         // Get path of cache files
         final NodeEnvironment nodeEnv = internalCluster().getInstance(NodeEnvironment.class);
         Path fileCachePath = nodeEnv.fileCacheNodePath().fileCachePath;
-        // Find all the files in the path
-        try (Stream<Path> paths = Files.walk(fileCachePath)) {
-            paths.filter(Files::isRegularFile).forEach(path -> {
-                // Testing moving the file to check the file is closed or not.
-                try {
-                    Files.move(path, path, StandardCopyOption.REPLACE_EXISTING);
-                } catch (IOException e) {
-                    fail("No exception is expected. The file can't be moved, so it may not be closed.");
-                }
-            });
-        } catch (NoSuchFileException e) {
-            logger.debug("--> the path for the cache files doesn't exist");
+
+        if (Files.exists(fileCachePath)) {
+            fail("Cache file path isn't deleted.");
+        } else {
+            logger.info("--> validated that the cache file path doesn't exist");
         }
     }
 }

server/src/main/java/org/opensearch/index/store/remote/filecache/FileCacheCleaner.java

@@ -11,6 +11,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.common.io.FileSystemUtils;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.env.NodeEnvironment;
 import org.opensearch.index.IndexModule;
@@ -60,6 +61,7 @@ public void beforeIndexShardDeleted(ShardId shardId, Settings settings) {
                         fileCache.remove(subPath.toRealPath());
                     }
                 }
+                FileSystemUtils.deleteSubDirectories(shardPath.getRootDataPath());
             }
         } catch (IOException ioe) {
             log.error(() -> new ParameterizedMessage("Error removing items from cache during shard deletion {})", shardId), ioe);