[Backport 0.6] Add retryable AOSS HTTP response

flint-core/src/main/scala/org/opensearch/flint/core/http/FlintRetryOptions.java

@@ -6,8 +6,12 @@
 package org.opensearch.flint.core.http;
 
 import static java.time.temporal.ChronoUnit.SECONDS;
+import static org.opensearch.flint.core.FlintOptions.SERVICE_NAME;
+import static org.opensearch.flint.core.FlintOptions.SERVICE_NAME_AOSS;
+import static org.opensearch.flint.core.FlintOptions.SERVICE_NAME_ES;
 
 import dev.failsafe.RetryPolicy;
+import dev.failsafe.RetryPolicyBuilder;
 import dev.failsafe.event.ExecutionAttemptedEvent;
 import dev.failsafe.function.CheckedPredicate;
 import java.time.Duration;
@@ -16,6 +20,7 @@
 import java.util.logging.Logger;
 import org.opensearch.action.bulk.BulkResponse;
 import org.opensearch.flint.core.http.handler.ExceptionClassNameFailurePredicate;
+import org.opensearch.flint.core.http.handler.HttpAOSSResultPredicate;
 import org.opensearch.flint.core.http.handler.HttpStatusCodeResultPredicate;
 import java.io.Serializable;
 
@@ -65,7 +70,7 @@ public boolean isRetryEnabled() {
    * @return Failsafe retry policy
    */
   public <T> RetryPolicy<T> getRetryPolicy() {
-    return RetryPolicy.<T>builder()
+    RetryPolicyBuilder<T> builder = RetryPolicy.<T>builder()
         // Backoff strategy config (can be configurable as needed in future)
         .withBackoff(1, 30, SECONDS)
         .withJitter(Duration.ofMillis(100))
@@ -75,8 +80,11 @@ public <T> RetryPolicy<T> getRetryPolicy() {
         .handleResultIf(new HttpStatusCodeResultPredicate<>(getRetryableHttpStatusCodes()))
         // Logging listener
         .onFailedAttempt(FlintRetryOptions::onFailure)
-        .onRetry(FlintRetryOptions::onRetry)
-        .build();
+        .onRetry(FlintRetryOptions::onRetry);
+    if (SERVICE_NAME_AOSS.equals(getServiceName())) {
+      builder.handleResultIf(new HttpAOSSResultPredicate<>());
+    }
+    return builder.build();
   }
 
   public RetryPolicy<BulkResponse> getBulkRetryPolicy(CheckedPredicate<BulkResponse> resultPredicate) {
@@ -101,6 +109,10 @@ private static <T> void onRetry(ExecutionAttemptedEvent<T> event) {
     LOG.warning("Retrying failed request at #" + event.getAttemptCount());
   }
 
+  private String getServiceName() {
+    return options.getOrDefault(SERVICE_NAME, SERVICE_NAME_ES);
+  }
+
   /**
    * @return maximum retry option value
    */

flint-core/src/main/scala/org/opensearch/flint/core/http/handler/HttpAOSSResultPredicate.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.flint.core.http.handler;
+
+import dev.failsafe.function.CheckedPredicate;
+import org.apache.http.HttpEntity;
+import org.apache.http.HttpResponse;
+import org.apache.http.entity.BufferedHttpEntity;
+import org.apache.http.util.EntityUtils;
+
+import java.util.logging.Logger;
+
+/**
+ * Failure handler based on HTTP response from AOSS.
+ *
+ * @param <T> result type (supposed to be HttpResponse for OS client)
+ */
+public class HttpAOSSResultPredicate<T> implements CheckedPredicate<T> {
+
+  private static final Logger LOG = Logger.getLogger(HttpAOSSResultPredicate.class.getName());
+
+  public static final int BAD_REQUEST_STATUS_CODE = 400;
+  public static final String RESOURCE_ALREADY_EXISTS_EXCEPTION_MESSAGE = "resource_already_exists_exception";
+
+  public HttpAOSSResultPredicate() { }
+
+  @Override
+  public boolean test(T result) throws Throwable {
+    LOG.info("Checking if response is retryable");
+
+    int statusCode = ((HttpResponse) result).getStatusLine().getStatusCode();
+    if (statusCode != BAD_REQUEST_STATUS_CODE) {
+      LOG.info("Status code " + statusCode + " is not " + BAD_REQUEST_STATUS_CODE + ". Check result: false");
+      return false;
+    }
+
+    HttpResponse response = (HttpResponse) result;
+    HttpEntity entity = response.getEntity();
+    if (entity == null) {
+      LOG.info("No response entity found. Check result: false");
+      return false;
+    }
+
+    // Buffer the entity to make it repeatable, so that this retry test does not consume the content stream,
+    // resulting in the request caller getting empty response
+    BufferedHttpEntity bufferedEntity = new BufferedHttpEntity(entity);
+    response.setEntity(bufferedEntity);
+
+    try {
+      String responseContent = EntityUtils.toString(bufferedEntity);
+      // Effectively restores the content stream of the response
+      bufferedEntity.getContent().reset();
+
+      boolean isRetryable = responseContent.contains(RESOURCE_ALREADY_EXISTS_EXCEPTION_MESSAGE);
+
+      LOG.info("Check retryable response result: " + isRetryable);
+      return isRetryable;
+    } catch (Exception e) {
+      LOG.info("Unable to parse response body. Check result: false");
+      return false;
+    }
+  }
+}

flint-core/src/test/scala/org/opensearch/flint/core/http/RetryableHttpAsyncClientSuite.scala

@@ -12,11 +12,13 @@ import java.util.concurrent.{ExecutionException, Future}
 
 import scala.collection.JavaConverters.mapAsJavaMapConverter
 
+import org.apache.http.HttpEntity
 import org.apache.http.HttpResponse
 import org.apache.http.concurrent.FutureCallback
 import org.apache.http.impl.nio.client.{CloseableHttpAsyncClient, HttpAsyncClientBuilder}
 import org.apache.http.nio.protocol.{HttpAsyncRequestProducer, HttpAsyncResponseConsumer}
 import org.apache.http.protocol.HttpContext
+import org.apache.http.util.EntityUtils
 import org.mockito.ArgumentMatchers.any
 import org.mockito.Mockito._
 import org.mockito.verification.VerificationMode
@@ -153,6 +155,23 @@ class RetryableHttpAsyncClientSuite extends AnyFlatSpec with BeforeAndAfter with
         expectFutureGetTimes = times(0))
   }
 
+  it should "retry if AOSS response is retryable" in {
+    retryableClient
+      .withOption("auth.servicename", "aoss")
+      .whenResponse(
+        400,
+        "OpenSearchStatusException[OpenSearch exception [type=resource_already_exists_exception,")
+      .shouldExecute(times(DEFAULT_MAX_RETRIES + 1))
+  }
+
+  it should "not apply retry policy for AOSS response if service is not AOSS" in {
+    retryableClient
+      .whenResponse(
+        400,
+        "OpenSearchStatusException[OpenSearch exception [type=resource_already_exists_exception,")
+      .shouldExecute(times(1))
+  }
+
   private def retryableClient: AssertionHelper = new AssertionHelper
 
   class AssertionHelper {
@@ -175,6 +194,17 @@ class RetryableHttpAsyncClientSuite extends AnyFlatSpec with BeforeAndAfter with
       this
     }
 
+    def whenResponse(statusCode: Int, responseMessage: String): AssertionHelper = {
+      val entity = mock[HttpEntity](RETURNS_DEEP_STUBS)
+      mockStatic(classOf[EntityUtils])
+      when(EntityUtils.toString(any[HttpEntity])).thenReturn(responseMessage)
+      val response = mock[HttpResponse](RETURNS_DEEP_STUBS)
+      when(response.getStatusLine.getStatusCode).thenReturn(statusCode)
+      when(response.getEntity).thenReturn(entity)
+      when(future.get()).thenReturn(response)
+      this
+    }
+
     def shouldExecute(expectExecuteTimes: VerificationMode): Unit = {
       shouldExecute(expectExecuteTimes, expectExecuteTimes)
     }