java/com/google/gerrit/server/ExceptionHook.java

// Copyright (C) 2019 The Android Open Source Project
//
// Licensed 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 com.google.gerrit.server;

import com.google.gerrit.extensions.annotations.ExtensionPoint;

/**
 * Allows implementors to control how certain exceptions should be handled.
 *
 * <p>This interface is intended to be implemented for cluster setups with multiple primary nodes to
 * control the behavior for handling exceptions that are thrown by a lower layer that handles the
 * consensus and synchronization between different server nodes. E.g. if an operation fails because
 * consensus for a Git update could not be achieved (e.g. due to slow responding server nodes) this
 * interface can be used to retry the request instead of failing it immediately.
 */
@ExtensionPoint
public interface ExceptionHook {
  /**
   * Whether an operation should be retried if it failed with the given throwable.
   *
   * <p>Only affects operations that are executed with {@link
   * com.google.gerrit.server.update.RetryHelper}.
   *
   * @param throwable throwable that was thrown while executing the operation
   * @return whether the operation should be retried
   */
  default boolean shouldRetry(Throwable throwable) {
    return false;
  }
}