content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.cassandra.sidecar.client.retry;
  
  import java.time.Duration;
  import java.util.concurrent.CompletableFuture;
  
  import io.netty.handler.codec.http.HttpResponseStatus;
  import org.apache.cassandra.sidecar.client.HttpResponse;
  import org.apache.cassandra.sidecar.client.exception.RetriesExhaustedException;
  import org.apache.cassandra.sidecar.common.request.Request;
  import org.apache.cassandra.sidecar.common.utils.TimeUtils;
  
  /**
   * A retry policy that attempts to execute the request once on each instance
   * until the first successful response is received, or fails if none were successful.
   *
   * Accepts optional minimum and maximum durations used to calculate random delay
   * before each retry attempt in order to avoid the thundering herd problem.
   *
   * Retries immediately without delay if minimum and maximum durations are not specified.
   */
  public class OncePerInstanceRetryPolicy extends RetryPolicy
  {
      private final Duration minimumDelay;
      private final Duration maximumDelay;
  
      /**
       * Instantiates {@link OncePerInstanceRetryPolicy} with no delay between retry attempts
       */
      public OncePerInstanceRetryPolicy()
      {
          this(Duration.ZERO, Duration.ZERO);
      }
  
      /**
       * Instantiates {@link OncePerInstanceRetryPolicy} with random delays between retry attempts
       *
       * @param minimumDelay duration of minimum possible retry delay, inclusive
       * @param maximumDelay duration of maximum possible retry delay, inclusive
       */
      public OncePerInstanceRetryPolicy(Duration minimumDelay, Duration maximumDelay)
      {
          super();
          this.minimumDelay = minimumDelay;
          this.maximumDelay = maximumDelay;
      }
  
      /**
       * {@inheritDoc}
       */
      @Override
      public void onResponse(CompletableFuture<HttpResponse> responseFuture,
                             Request request,
                             HttpResponse response,
                             Throwable throwable,
                             int attempts,
                             boolean canRetryOnADifferentHost,
                             RetryAction retryAction)
      {
          if (response != null && response.statusCode() == HttpResponseStatus.OK.code())
          {
              responseFuture.complete(response);
          }
          else if (canRetryOnADifferentHost)
          {
              retryAction.retry(attempts + 1, TimeUtils.randomDuration(minimumDelay, maximumDelay).toMillis());
          }
          else
          {
              responseFuture.completeExceptionally(RetriesExhaustedException.of(attempts, request, response, throwable));
          }
      }
  }
  