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.beam.runners.fnexecution.environment;
  
  import javax.annotation.concurrent.ThreadSafe;
  import org.apache.beam.model.pipeline.v1.RunnerApi.Environment;
  import org.apache.beam.runners.fnexecution.control.InstructionRequestHandler;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * A {@link RemoteEnvironment} that wraps a running Docker container.
   *
   * <p>A {@link DockerContainerEnvironment} owns both the underlying docker container that it
   * communicates with an the {@link InstructionRequestHandler} that it uses to do so.
   */
  @ThreadSafe
  class DockerContainerEnvironment implements RemoteEnvironment {
  
    private static final Logger LOG = LoggerFactory.getLogger(DockerContainerEnvironment.class);
  
    static DockerContainerEnvironment create(
        DockerCommand docker,
        Environment environment,
        String containerId,
        InstructionRequestHandler instructionHandler,
        boolean retainDockerContainer) {
      return new DockerContainerEnvironment(
          docker, environment, containerId, instructionHandler, retainDockerContainer);
    }
  
    private final Object lock = new Object();
    private final DockerCommand docker;
    private final Environment environment;
    private final String containerId;
    private final InstructionRequestHandler instructionHandler;
    private final boolean retainDockerContainer;
  
    private boolean isClosed = false;
  
    private DockerContainerEnvironment(
        DockerCommand docker,
        Environment environment,
        String containerId,
        InstructionRequestHandler instructionHandler,
        boolean retainDockerContainer) {
      this.docker = docker;
      this.environment = environment;
      this.containerId = containerId;
      this.instructionHandler = instructionHandler;
      this.retainDockerContainer = retainDockerContainer;
    }
  
    @Override
    public Environment getEnvironment() {
      return environment;
    }
  
    @Override
    public InstructionRequestHandler getInstructionRequestHandler() {
      return instructionHandler;
    }
  
    /**
     * Closes this remote docker environment. The associated {@link InstructionRequestHandler} should
     * not be used after calling this.
     */
    @Override
    public void close() throws Exception {
      synchronized (lock) {
        // The running docker container and instruction handler should each only be terminated once.
        // Do nothing if we have already requested termination.
        if (!isClosed) {
          isClosed = true;
          instructionHandler.close();
          String containerLogs = docker.getContainerLogs(containerId);
          LOG.info("Closing Docker container {}. Logs:\n{}", containerId, containerLogs);
          docker.killContainer(containerId);
          if (!retainDockerContainer) {
            docker.removeContainer(containerId);
          }
        }
      }
    }
  }
  