content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.grpc;
  
  import alluxio.retry.ExponentialBackoffRetry;
  import alluxio.retry.RetryUtils;
  import alluxio.security.authentication.AuthenticationServer;
  
  import com.google.common.annotations.VisibleForTesting;
  import com.google.common.base.MoreObjects;
  import com.google.common.io.Closer;
  import io.grpc.Server;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.io.IOException;
  import java.util.concurrent.TimeUnit;
  
  /**
   * An authenticated gRPC server. Corresponding gRPC channels to this server should be build by
   * {@link GrpcChannelBuilder}.
   */
  public final class GrpcServer {
    private static final Logger LOG = LoggerFactory.getLogger(GrpcServer.class);
  
    /** Internal server reference. */
    private final Server mServer;
    /** Authentication server for this server. */
    private final AuthenticationServer mAuthServer;
    /** Closer for closing resources during shutdown. */
    private final Closer mCloser;
  
    /** Set to TRUE when the server has been successfully started. **/
    private volatile boolean mStarted = false;
    private final long mServerShutdownTimeoutMs;
  
    /**
     * Create a new instance of {@link GrpcServer}.
     *
     * @param server the wrapped server
     * @param authServer the authentication server
     * @param closer resources to close during shutting down of this server
     * @param serverShutdownTimeoutMs server shutdown timeout in milliseconds
     */
    public GrpcServer(Server server, AuthenticationServer authServer, Closer closer,
        long serverShutdownTimeoutMs) {
      mServer = server;
      mAuthServer = authServer;
      mCloser = closer;
      mServerShutdownTimeoutMs = serverShutdownTimeoutMs;
    }
  
    /**
     * @return the authentication server associated with this server
     */
    @VisibleForTesting
    public AuthenticationServer getAuthenticationServer() {
      return mAuthServer;
    }
  
    /**
     * Start serving.
     *
     * @return this instance of {@link GrpcServer}
     * @throws IOException when unable to start serving
     */
    public GrpcServer start() throws IOException {
      RetryUtils.retry("Starting gRPC server", mServer::start,
          new ExponentialBackoffRetry(100, 500, 5));
      mStarted = true;
      return this;
    }
  
    /**
     * @return the port that server is bound to, or null if the server is not bound to an address yet
     */
    public int getBindPort() {
      return mServer.getPort();
    }
  
    /**
     * Shuts down the server.
     *
     * @return {@code true} if the server was successfully terminated
     */
    public boolean shutdown() {
      // Stop accepting new connections.
      mServer.shutdown();
      // Close resources that potentially owns active streams.
      try {
        mCloser.close();
      } catch (IOException e) {
        LOG.error("Failed to close resources during shutdown.", e);
        // Do nothing.
      }
      // Force shutdown remaining calls.
      mServer.shutdownNow();
      // Wait until server terminates.
      try {
        return mServer.awaitTermination(mServerShutdownTimeoutMs, TimeUnit.MILLISECONDS);
      } catch (InterruptedException ie) {
        Thread.currentThread().interrupt();
        return false;
      }
    }
  
    /**
     * Waits until the server is terminated.
     */
    public void awaitTermination() {
      try {
        mServer.awaitTermination();
      } catch (InterruptedException ie) {
        Thread.currentThread().interrupt();
        // Allow thread to exit.
      }
    }
  
    /**
     * @return true if server is serving
     */
    public boolean isServing() {
      return mStarted && !mServer.isShutdown() || !mServer.isTerminated();
    }
  
    @Override
    public String toString() {
      return MoreObjects.toStringHelper(this)
          .add("InternalServer", mServer)
          .add("AuthServerType", mAuthServer.getClass().getSimpleName())
          .toString();
    }
  }
  