Exception crashing the whole app when broker is killed

[Tychus]

Opening this again as i'm having the same issue.

I'm handling close error and blocked everything works fine when the broker is closed properly and the app will keep trying to reconnect as expected. But when i kill the broker (i'm running it through docker) i get both the error and close events as described in the doc but the app will crash right after.

  private async connect(): Promise<void> {
    if (this.connected) {
      return;
    }
    await this.connectionLock.runExclusive(async () => {
      if (this.connected) {
        return;
      }
      await pRetry(
        async () => {
          logger.info('Attempting rabbitMQ connection');
          this.connection = await client.connect(this.connectionSettings.getConnectionString());
        },
        {
          onFailedAttempt: (error) => {
            logger.error(`RabbitMq connection failed. Attempt ${error.attemptNumber}. Error: ${error.message}`);
            if (error.retriesLeft === 0) {
              this.connected = false;
              throw Error(`Failed to establish rabbitMq connection after ${this.maxConnectionRetry} attempts`);
            }
          },
          factor: 2,
          minTimeout: 1000,
          maxTimeout: 5000,
          retries: this.maxConnectionRetry,
        },
      );
      logger.info('RabbitMq connection successful');
      this.setEventListeners();
      this.eventEmitter.emit('connected');
      this.connected = true;
    });
  }

private setEventListeners(): void {
    this.connection.on('close', async (message) => {
      logger.warn(`RabbitMq connection lost: ${message}`);
      this.eventEmitter.emit('disconnected');
      await this.handleErrorEvents();
    });

    this.connection.on('error', async (error) => {
      logger.error(`RabbitMq connection error: ${error}`);
      this.eventEmitter.emit('error');
      await this.handleErrorEvents();
    });

    this.connection.on('blocked', async (reason) => {
      logger.warn(`RabbitMq connection blocked: ${reason}`);
      this.eventEmitter.emit('blocked');
      await this.disconnect();
      await this.handleErrorEvents();
    });
}

private async handleErrorEvents(): Promise<void> {
    this.connected = false;
    await this.connect();
  }

async disconnect(): Promise<void> {
  await this.connection.close();
  this.eventEmitter.emit('disconnected');
  this.connected = false;
}

Exception looks something like this:

[Node] 2022-06-01T08:23:12.546Z [error]: RabbitMq connection error: Error: Unexpected close ( connection receiving error event)
[Node] 2022-06-01T08:23:12.549Z [warn]: RabbitMq connection lost: Error: Unexpected close (connection receiving close event)
[Node] 2022-06-01T08:23:12.551Z [warn]: Bus connection lost. saving events for publishing on reconnection (publisher handling disconnect)
[Node] 2022-06-01T08:23:12.555Z [info]: Attempting rabbitMQ connection
[Node] Error: Unhandled error. (undefined)
[Node]     at new NodeError (node:internal/errors:372:5)
[Node]     at EventEmitter.emit (node:events:516:17)
[Node]     at EventEmitter.emit (node:domain:475:12)
[Node]     at ChannelModel.<anonymous> (/home/ty/Projects/rmq/node_modules/rmqlib/dist/messaging/rabbitMqBus/rabbitMqConnection.js:80:31)
[Node]     at ChannelModel.emit (node:events:527:28)
[Node]     at ChannelModel.emit (node:domain:475:12)
[Node]     at Connection.emit (node:events:527:28)
[Node]     at Connection.emit (node:domain:475:12)
[Node]     at Connection.C.onSocketError (/home/ty/Projects/rmq/node_modules/amqplib/lib/connection.js:353:10)
[Node]     at Socket.emit (node:events:539:35)
[Node]     at Socket.emit (node:domain:475:12)
[Node]     at endReadableNT (node:internal/streams/readable:1345:12)
[Node]     at processTicksAndRejections (node:internal/process/task_queues:83:21)
[Node] [nodemon] app crashed - waiting for file changes before starting...

node -v -> v16.15.0
PS: excuse the code i'm no TS/JS dev just trying to make things work

Originally posted by @Tychus in #338 (comment)

[cressie176]

   this.connection.on('error', async (error) => {
      logger.error(`RabbitMq connection error: ${error}`);
      this.eventEmitter.emit('error'); // <-- This will crash your application
      await this.handleErrorEvents();
    });

You're re-emitting the the error event.

If an EventEmitter does not have at least one listener registered for the 'error' event, and an 'error' event is emitted, the error is thrown, a stack trace is printed, and the Node.js process exits.

https://nodejs.org/api/events.html#error-events

[Tychus]

The more your know. I wasn't actually listening to that event in the start because the lib will send a disconnect after it but it kept crashing the app and i found issues here similar. Thanks for taking the time. Closing the issue

[AmosSpark]

   this.connection.on('error', async (error) => {
      logger.error(`RabbitMq connection error: ${error}`);
      this.eventEmitter.emit('error'); // <-- This will crash your application
      await this.handleErrorEvents();
    });

You're re-emitting the the error event.

If an EventEmitter does not have at least one listener registered for the 'error' event, and an 'error' event is emitted, the error is thrown, a stack trace is printed, and the Node.js process exits.

https://nodejs.org/api/events.html#error-events

Thank you!