Method close

lib/connection.js:732–777

* Closes the socket (if not already closed) and cancels all in-flight requests. * Multiple calls to this method have no additional side-effects. * @param {Function} [callback]

(callback)

   * @param {Function} [callback]
   */
  close(callback) {
    callback = callback || utils.noop;

    if (!this.connected && !this.isSocketOpen) {
      return callback();
    }

    this.connected = false;
    // Drain is never going to be emitted, once it is set to closed
    this.removeAllListeners('drain');
    this.clearAndInvokePending();

    if (!this.isSocketOpen) {
      return callback();
    }

    // Set the socket as closed now (before socket.end() is called) to avoid being invoked more than once
    this.isSocketOpen = false;
    this.log('verbose', `Closing connection to ${this.endpointFriendlyName}`);
    const self = this;

    // If server doesn't acknowledge the half-close within connection timeout, destroy the socket.
    const endTimeout = setTimeout(() => {
      this.log('info', `${this.endpointFriendlyName} did not respond to connection close within ` +
        `${this.options.socketOptions.connectTimeout}ms, destroying connection`);
      this.netClient.destroy();
    }, this.options.socketOptions.connectTimeout);

    this.netClient.once('close', function (hadError) {
      clearTimeout(endTimeout);
      if (hadError) {
        self.log('info', 'The socket closed with a transmission error');
      }
      setImmediate(callback);
    });

    // At this point, the error event can be triggered because:
    // - It's connected and writes haven't completed yet
    // - The server abruptly closed its end of the connection (ECONNRESET) as a result of protocol error / auth error
    // We need to remove any listeners and make sure we callback are pending writes
    this.netClient.removeAllListeners('error');
    this.netClient.on('error', err => this.clearAndInvokePending(err));

    // Half-close the socket, it will result in 'close' event being fired
    this.netClient.end();
  }

  /**
   * Gets the local IP address to which this connection socket is bound to.