Refactoring gated and ref-counted interfaces and their implementations (

opensearch-project#2396)

* Reducing duplication in plugins around ref-counted releasable classes

Both AmazonEc2Reference and AmazonS3Reference duplicate the same logic - a subclass of AbstractRefCounted that also implements Releasable. This change centralizes this paradigm into a AbstractRefCountedReleasable class and supports both clients via generics. It also updates all fetching implementations to use the get() method instead of client()

Signed-off-by: Kartik Ganesh <gkart@amazon.com>

* Introduce Reference classes for the Closeable and AutoCloseable interfaces

These classes allow you to wrap a reference instance with an onClose runnable that is executed when close() is invoked. Two separate classes are needed because the close() signatures for the two interfaces are different. This change takes the first step to have implementing classes extend from these generic superclasses, before attempting to remove the subclasses entirely. The get() method is also replaced throughout the code base.

Note that there is also a separate Releasable interface that has a similar access pattern, but is implemented separately. This is used in AbstractRefCountedReleasable introduced in a prior commit

Signed-off-by: Kartik Ganesh <gkart@amazon.com>

* More improvements and refactoring

* Functionality around one-way gating is now moved to a dedicated class - OneWayGate. This replaces duplicate functionality throughout the code.
* The two *Reference classes have been renamed to Gated* since that better represents their functionality
* The AbstractRefCountedReleasable has been improved to no longer be abstract by accepting the shutdown hook. This removes the need for the inner class in ReleasableBytesReference, and further simplifies the plugin subclasses (these could probably be removed entirely).
* Finally, unit tests have been added for some classes

Signed-off-by: Kartik Ganesh <gkart@amazon.com>

* Added tests for GatedCloseable

Also updated the license information in GatedAutoCloseableTests

Signed-off-by: Kartik Ganesh <gkart@amazon.com>

* Fixing license information in new files

Signed-off-by: Kartik Ganesh <gkart@amazon.com>

* Added unit tests for RefCountedReleasable

Signed-off-by: Kartik Ganesh <gkart@amazon.com>

libs/core/src/test/java/org/opensearch/common/util/concurrent/RefCountedTests.java

@@ -31,13 +31,13 @@
 
 package org.opensearch.common.util.concurrent;
 
+import org.opensearch.common.concurrent.OneWayGate;
 import org.opensearch.test.OpenSearchTestCase;
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
 import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.atomic.AtomicBoolean;
 
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.is;
@@ -138,19 +138,19 @@ public void run() {
 
     private final class MyRefCounted extends AbstractRefCounted {
 
-        private final AtomicBoolean closed = new AtomicBoolean(false);
+        private final OneWayGate gate = new OneWayGate();
 
         MyRefCounted() {
             super("test");
         }
 
         @Override
         protected void closeInternal() {
-            this.closed.set(true);
+            gate.close();
         }
 
         public void ensureOpen() {
-            if (closed.get()) {
+            if (gate.isClosed()) {
                 assert this.refCount() == 0;
                 throw new IllegalStateException("closed");
             }

plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AmazonEc2Reference.java

@@ -33,42 +33,15 @@
 package org.opensearch.discovery.ec2;
 
 import com.amazonaws.services.ec2.AmazonEC2;
-
-import org.opensearch.common.lease.Releasable;
-import org.opensearch.common.util.concurrent.AbstractRefCounted;
+import org.opensearch.common.concurrent.RefCountedReleasable;
 
 /**
  * Handles the shutdown of the wrapped {@link AmazonEC2} using reference
  * counting.
  */
-public class AmazonEc2Reference extends AbstractRefCounted implements Releasable {
-
-    private final AmazonEC2 client;
+public class AmazonEc2Reference extends RefCountedReleasable<AmazonEC2> {
 
     AmazonEc2Reference(AmazonEC2 client) {
-        super("AWS_EC2_CLIENT");
-        this.client = client;
+        super("AWS_EC2_CLIENT", client, client::shutdown);
     }
-
-    /**
-     * Call when the client is not needed anymore.
-     */
-    @Override
-    public void close() {
-        decRef();
-    }
-
-    /**
-     * Returns the underlying `AmazonEC2` client. All method calls are permitted BUT
-     * NOT shutdown. Shutdown is called when reference count reaches 0.
-     */
-    public AmazonEC2 client() {
-        return client;
-    }
-
-    @Override
-    protected void closeInternal() {
-        client.shutdown();
-    }
-
 }

plugins/discovery-ec2/src/main/java/org/opensearch/discovery/ec2/AwsEc2SeedHostsProvider.java

@@ -129,7 +129,7 @@ protected List<TransportAddress> fetchDynamicNodes() {
             // NOTE: we don't filter by security group during the describe instances request for two reasons:
             // 1. differences in VPCs require different parameters during query (ID vs Name)
             // 2. We want to use two different strategies: (all security groups vs. any security groups)
-            descInstances = SocketAccess.doPrivileged(() -> clientReference.client().describeInstances(buildDescribeInstancesRequest()));
+            descInstances = SocketAccess.doPrivileged(() -> clientReference.get().describeInstances(buildDescribeInstancesRequest()));
         } catch (final AmazonClientException e) {
             logger.info("Exception while retrieving instance list from AWS API: {}", e.getMessage());
             logger.debug("Full exception:", e);

plugins/discovery-ec2/src/test/java/org/opensearch/discovery/ec2/Ec2DiscoveryPluginTests.java

@@ -103,15 +103,15 @@ public void testNodeAttributesErrorLenient() throws Exception {
 
     public void testDefaultEndpoint() throws IOException {
         try (Ec2DiscoveryPluginMock plugin = new Ec2DiscoveryPluginMock(Settings.EMPTY)) {
-            final String endpoint = ((AmazonEC2Mock) plugin.ec2Service.client().client()).endpoint;
+            final String endpoint = ((AmazonEC2Mock) plugin.ec2Service.client().get()).endpoint;
             assertThat(endpoint, is(""));
         }
     }
 
     public void testSpecificEndpoint() throws IOException {
         final Settings settings = Settings.builder().put(Ec2ClientSettings.ENDPOINT_SETTING.getKey(), "ec2.endpoint").build();
         try (Ec2DiscoveryPluginMock plugin = new Ec2DiscoveryPluginMock(settings)) {
-            final String endpoint = ((AmazonEC2Mock) plugin.ec2Service.client().client()).endpoint;
+            final String endpoint = ((AmazonEC2Mock) plugin.ec2Service.client().get()).endpoint;
             assertThat(endpoint, is("ec2.endpoint"));
         }
     }
@@ -150,7 +150,7 @@ public void testClientSettingsReInit() throws IOException {
         try (Ec2DiscoveryPluginMock plugin = new Ec2DiscoveryPluginMock(settings1)) {
             try (AmazonEc2Reference clientReference = plugin.ec2Service.client()) {
                 {
-                    final AWSCredentials credentials = ((AmazonEC2Mock) clientReference.client()).credentials.getCredentials();
+                    final AWSCredentials credentials = ((AmazonEC2Mock) clientReference.get()).credentials.getCredentials();
                     assertThat(credentials.getAWSAccessKeyId(), is("ec2_access_1"));
                     assertThat(credentials.getAWSSecretKey(), is("ec2_secret_1"));
                     if (mockSecure1HasSessionToken) {
@@ -159,32 +159,32 @@ public void testClientSettingsReInit() throws IOException {
                     } else {
                         assertThat(credentials, instanceOf(BasicAWSCredentials.class));
                     }
-                    assertThat(((AmazonEC2Mock) clientReference.client()).configuration.getProxyUsername(), is("proxy_username_1"));
-                    assertThat(((AmazonEC2Mock) clientReference.client()).configuration.getProxyPassword(), is("proxy_password_1"));
-                    assertThat(((AmazonEC2Mock) clientReference.client()).configuration.getProxyHost(), is("proxy_host_1"));
-                    assertThat(((AmazonEC2Mock) clientReference.client()).configuration.getProxyPort(), is(881));
-                    assertThat(((AmazonEC2Mock) clientReference.client()).endpoint, is("ec2_endpoint_1"));
+                    assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyUsername(), is("proxy_username_1"));
+                    assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyPassword(), is("proxy_password_1"));
+                    assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyHost(), is("proxy_host_1"));
+                    assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyPort(), is(881));
+                    assertThat(((AmazonEC2Mock) clientReference.get()).endpoint, is("ec2_endpoint_1"));
                 }
                 // reload secure settings2
                 plugin.reload(settings2);
                 // client is not released, it is still using the old settings
                 {
-                    final AWSCredentials credentials = ((AmazonEC2Mock) clientReference.client()).credentials.getCredentials();
+                    final AWSCredentials credentials = ((AmazonEC2Mock) clientReference.get()).credentials.getCredentials();
                     if (mockSecure1HasSessionToken) {
                         assertThat(credentials, instanceOf(BasicSessionCredentials.class));
                         assertThat(((BasicSessionCredentials) credentials).getSessionToken(), is("ec2_session_token_1"));
                     } else {
                         assertThat(credentials, instanceOf(BasicAWSCredentials.class));
                     }
-                    assertThat(((AmazonEC2Mock) clientReference.client()).configuration.getProxyUsername(), is("proxy_username_1"));
-                    assertThat(((AmazonEC2Mock) clientReference.client()).configuration.getProxyPassword(), is("proxy_password_1"));
-                    assertThat(((AmazonEC2Mock) clientReference.client()).configuration.getProxyHost(), is("proxy_host_1"));
-                    assertThat(((AmazonEC2Mock) clientReference.client()).configuration.getProxyPort(), is(881));
-                    assertThat(((AmazonEC2Mock) clientReference.client()).endpoint, is("ec2_endpoint_1"));
+                    assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyUsername(), is("proxy_username_1"));
+                    assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyPassword(), is("proxy_password_1"));
+                    assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyHost(), is("proxy_host_1"));
+                    assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyPort(), is(881));
+                    assertThat(((AmazonEC2Mock) clientReference.get()).endpoint, is("ec2_endpoint_1"));
                 }
             }
             try (AmazonEc2Reference clientReference = plugin.ec2Service.client()) {
-                final AWSCredentials credentials = ((AmazonEC2Mock) clientReference.client()).credentials.getCredentials();
+                final AWSCredentials credentials = ((AmazonEC2Mock) clientReference.get()).credentials.getCredentials();
                 assertThat(credentials.getAWSAccessKeyId(), is("ec2_access_2"));
                 assertThat(credentials.getAWSSecretKey(), is("ec2_secret_2"));
                 if (mockSecure2HasSessionToken) {
@@ -193,11 +193,11 @@ public void testClientSettingsReInit() throws IOException {
                 } else {
                     assertThat(credentials, instanceOf(BasicAWSCredentials.class));
                 }
-                assertThat(((AmazonEC2Mock) clientReference.client()).configuration.getProxyUsername(), is("proxy_username_2"));
-                assertThat(((AmazonEC2Mock) clientReference.client()).configuration.getProxyPassword(), is("proxy_password_2"));
-                assertThat(((AmazonEC2Mock) clientReference.client()).configuration.getProxyHost(), is("proxy_host_2"));
-                assertThat(((AmazonEC2Mock) clientReference.client()).configuration.getProxyPort(), is(882));
-                assertThat(((AmazonEC2Mock) clientReference.client()).endpoint, is("ec2_endpoint_2"));
+                assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyUsername(), is("proxy_username_2"));
+                assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyPassword(), is("proxy_password_2"));
+                assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyHost(), is("proxy_host_2"));
+                assertThat(((AmazonEC2Mock) clientReference.get()).configuration.getProxyPort(), is(882));
+                assertThat(((AmazonEC2Mock) clientReference.get()).endpoint, is("ec2_endpoint_2"));
             }
         }
     }

plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/AmazonS3Reference.java

@@ -32,45 +32,17 @@
 
 package org.opensearch.repositories.s3;
 
-import org.opensearch.common.util.concurrent.AbstractRefCounted;
-
 import com.amazonaws.services.s3.AmazonS3;
 import com.amazonaws.services.s3.AmazonS3Client;
-
-import org.opensearch.common.lease.Releasable;
+import org.opensearch.common.concurrent.RefCountedReleasable;
 
 /**
  * Handles the shutdown of the wrapped {@link AmazonS3Client} using reference
  * counting.
  */
-public class AmazonS3Reference extends AbstractRefCounted implements Releasable {
-
-    private final AmazonS3 client;
+public class AmazonS3Reference extends RefCountedReleasable<AmazonS3> {
 
     AmazonS3Reference(AmazonS3 client) {
-        super("AWS_S3_CLIENT");
-        this.client = client;
-    }
-
-    /**
-     * Call when the client is not needed anymore.
-     */
-    @Override
-    public void close() {
-        decRef();
+        super("AWS_S3_CLIENT", client, client::shutdown);
     }
-
-    /**
-     * Returns the underlying `AmazonS3` client. All method calls are permitted BUT
-     * NOT shutdown. Shutdown is called when reference count reaches 0.
-     */
-    public AmazonS3 client() {
-        return client;
-    }
-
-    @Override
-    protected void closeInternal() {
-        client.shutdown();
-    }
-
 }

plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3BlobContainer.java

@@ -101,7 +101,7 @@ class S3BlobContainer extends AbstractBlobContainer {
     @Override
     public boolean blobExists(String blobName) {
         try (AmazonS3Reference clientReference = blobStore.clientReference()) {
-            return SocketAccess.doPrivileged(() -> clientReference.client().doesObjectExist(blobStore.bucket(), buildKey(blobName)));
+            return SocketAccess.doPrivileged(() -> clientReference.get().doesObjectExist(blobStore.bucket(), buildKey(blobName)));
         } catch (final Exception e) {
             throw new BlobStoreException("Failed to check if blob [" + blobName + "] exists", e);
         }
@@ -169,13 +169,13 @@ public DeleteResult delete() throws IOException {
                 ObjectListing list;
                 if (prevListing != null) {
                     final ObjectListing finalPrevListing = prevListing;
-                    list = SocketAccess.doPrivileged(() -> clientReference.client().listNextBatchOfObjects(finalPrevListing));
+                    list = SocketAccess.doPrivileged(() -> clientReference.get().listNextBatchOfObjects(finalPrevListing));
                 } else {
                     final ListObjectsRequest listObjectsRequest = new ListObjectsRequest();
                     listObjectsRequest.setBucketName(blobStore.bucket());
                     listObjectsRequest.setPrefix(keyPath);
                     listObjectsRequest.setRequestMetricCollector(blobStore.listMetricCollector);
-                    list = SocketAccess.doPrivileged(() -> clientReference.client().listObjects(listObjectsRequest));
+                    list = SocketAccess.doPrivileged(() -> clientReference.get().listObjects(listObjectsRequest));
                 }
                 final List<String> blobsToDelete = new ArrayList<>();
                 list.getObjectSummaries().forEach(s3ObjectSummary -> {
@@ -236,7 +236,7 @@ private void doDeleteBlobs(List<String> blobNames, boolean relative) throws IOEx
                         .map(DeleteObjectsRequest.KeyVersion::getKey)
                         .collect(Collectors.toList());
                     try {
-                        clientReference.client().deleteObjects(deleteRequest);
+                        clientReference.get().deleteObjects(deleteRequest);
                         outstanding.removeAll(keysInRequest);
                     } catch (MultiObjectDeleteException e) {
                         // We are sending quiet mode requests so we can't use the deleted keys entry on the exception and instead
@@ -324,9 +324,9 @@ private static List<ObjectListing> executeListing(AmazonS3Reference clientRefere
             ObjectListing list;
             if (prevListing != null) {
                 final ObjectListing finalPrevListing = prevListing;
-                list = SocketAccess.doPrivileged(() -> clientReference.client().listNextBatchOfObjects(finalPrevListing));
+                list = SocketAccess.doPrivileged(() -> clientReference.get().listNextBatchOfObjects(finalPrevListing));
             } else {
-                list = SocketAccess.doPrivileged(() -> clientReference.client().listObjects(listObjectsRequest));
+                list = SocketAccess.doPrivileged(() -> clientReference.get().listObjects(listObjectsRequest));
             }
             results.add(list);
             if (list.isTruncated()) {
@@ -374,7 +374,7 @@ void executeSingleUpload(final S3BlobStore blobStore, final String blobName, fin
         putRequest.setRequestMetricCollector(blobStore.putMetricCollector);
 
         try (AmazonS3Reference clientReference = blobStore.clientReference()) {
-            SocketAccess.doPrivilegedVoid(() -> { clientReference.client().putObject(putRequest); });
+            SocketAccess.doPrivilegedVoid(() -> { clientReference.get().putObject(putRequest); });
         } catch (final AmazonClientException e) {
             throw new IOException("Unable to upload object [" + blobName + "] using a single upload", e);
         }
@@ -413,7 +413,7 @@ void executeMultipartUpload(final S3BlobStore blobStore, final String blobName,
         }
         try (AmazonS3Reference clientReference = blobStore.clientReference()) {
 
-            uploadId.set(SocketAccess.doPrivileged(() -> clientReference.client().initiateMultipartUpload(initRequest).getUploadId()));
+            uploadId.set(SocketAccess.doPrivileged(() -> clientReference.get().initiateMultipartUpload(initRequest).getUploadId()));
             if (Strings.isEmpty(uploadId.get())) {
                 throw new IOException("Failed to initialize multipart upload " + blobName);
             }
@@ -439,7 +439,7 @@ void executeMultipartUpload(final S3BlobStore blobStore, final String blobName,
                 }
                 bytesCount += uploadRequest.getPartSize();
 
-                final UploadPartResult uploadResponse = SocketAccess.doPrivileged(() -> clientReference.client().uploadPart(uploadRequest));
+                final UploadPartResult uploadResponse = SocketAccess.doPrivileged(() -> clientReference.get().uploadPart(uploadRequest));
                 parts.add(uploadResponse.getPartETag());
             }
 
@@ -456,7 +456,7 @@ void executeMultipartUpload(final S3BlobStore blobStore, final String blobName,
                 parts
             );
             complRequest.setRequestMetricCollector(blobStore.multiPartUploadMetricCollector);
-            SocketAccess.doPrivilegedVoid(() -> clientReference.client().completeMultipartUpload(complRequest));
+            SocketAccess.doPrivilegedVoid(() -> clientReference.get().completeMultipartUpload(complRequest));
             success = true;
 
         } catch (final AmazonClientException e) {
@@ -465,7 +465,7 @@ void executeMultipartUpload(final S3BlobStore blobStore, final String blobName,
             if ((success == false) && Strings.hasLength(uploadId.get())) {
                 final AbortMultipartUploadRequest abortRequest = new AbortMultipartUploadRequest(bucketName, blobName, uploadId.get());
                 try (AmazonS3Reference clientReference = blobStore.clientReference()) {
-                    SocketAccess.doPrivilegedVoid(() -> clientReference.client().abortMultipartUpload(abortRequest));
+                    SocketAccess.doPrivilegedVoid(() -> clientReference.get().abortMultipartUpload(abortRequest));
                 }
             }
         }

plugins/repository-s3/src/main/java/org/opensearch/repositories/s3/S3RetryingInputStream.java

@@ -110,7 +110,7 @@ private void openStream() throws IOException {
                     + end;
                 getObjectRequest.setRange(Math.addExact(start, currentOffset), end);
             }
-            final S3Object s3Object = SocketAccess.doPrivileged(() -> clientReference.client().getObject(getObjectRequest));
+            final S3Object s3Object = SocketAccess.doPrivileged(() -> clientReference.get().getObject(getObjectRequest));
             this.currentStreamLastOffset = Math.addExact(Math.addExact(start, currentOffset), getStreamLength(s3Object));
             this.currentStream = s3Object.getObjectContent();
         } catch (final AmazonClientException e) {