NodeJS: Publish AMQP message on realtime event

Question

I'm using amqplib to publish messages to my RabbitMQ server. This is working quite well, but I think I can optimize the way I do it.

The idea is to listen to a serial port to get data from it (which is continuously sent) and publish this data to the AMQP channel. Then the subscribers get the data for two needs:

• display real time value (with socket.io) on a web front
• store a sample (each minute) in a MySQL Database (with another Node or PHP code)

Here is my code:

function on_connect(err, conn) {
  if (err !== null) return bail(err);

  function on_channel_open(err, ch) {
    if (err !== null) return bail(err, conn);
    ch.assertQueue(amqp_channel, {durable: false}, function(err, ok) {
      if (err !== null) return bail(err, conn);

      var trameEvents = teleinfo('/dev/ttyAMA0');
      trameEvents.on('tramedecodee', function (data) {

        ch.sendToQueue(amqp_channel, new Buffer(data));
        console.log("Sent '%s'", data);

      });

      //log errors
      trameEvents.on('error', function (err) {
        console.log(util.inspect(err));
      });

      ch.close(function() { conn.close(); });
    });
  }

  conn.createChannel(on_channel_open);
}

The problem is the trameEvents returns sometimes an error, and then the whole application dies:

/home/pi/nodejs/teleinfo-amqp-publisher/node_modules/amqplib/lib/channel.js:149
    throw new IllegalOperationError(msg, stack);
          ^
IllegalOperationError: Channel closed
    at Channel.<anonymous> (/home/pi/nodejs/teleinfo-amqp-publisher/node_modules/amqplib/lib/channel.js:149:11)

So I'm looking for a way to make a robust node application doing these tasks. Any idea?

Thanks

Answer 1

ch.close(function() { conn.close(); });

you're telling the channel to close, which is causing the error you are seeing.

take that line of code out of your app and it should run indefinitely.