[rabbitmq-discuss] pika and node.amqp interop

[Dan Tenenbaum]

Hi,

I am new to rabbitmq. I got the python "getting started" examples to work
just fine.
I would like to be able to send messages between node.js (using node.amqp)
and python/pika.

I can successfully receive a message in node.js using this code:

[receiver - node.js]
var sys = require('sys');
var amqp = require('./amqp');

var connection = amqp.createConnection({ host: 'localhost' });

// Wait for connection to become established.
connection.addListener('ready', function () {
  // Create a queue and bind to all messages.
  // Use the default 'amq.topic' exchange

  var q = connection.queue('my-queue');
  // Catch all messages
  q.bind('#');


  // Receive messages
  q.subscribe(function (message) {
    // Print messages to stdout
    sys.puts(sys.inspect(message));
  });
});

[sender - python/pika]
#!/usr/bin/env python
import pika

connection = pika.AsyncoreConnection(pika.ConnectionParameters(
        host='localhost'))
channel = connection.channel()


channel.basic_publish(exchange='',
                      routing_key='my-queue',
                      body='Hello World!')
print " [x] Sent 'Hello World!'"
connection.close()

But I can't go the other way. I'm not sure that the message sent by node.js
is going anywhere. I've looked at the unit tests for node.amqp (they all
pass) but there is something I am missing, probably to do with exchanges or
something. I'd like to do something like this:

[sender - node.js]
var sys = require('sys');
var amqp = require('./amqp');

var connection = amqp.createConnection({ host: 'localhost' });

// Wait for connection to become established.
connection.addListener('ready', function () {
  // Create a queue and bind to all messages.
  // Use the default 'amq.topic' exchange
  connection.publish("my-queue", {random_key:"this is my message"});
  connection.end();

});

[receiver - python/pika]
#!/usr/bin/env python
import pika
import sys

connection = pika.AsyncoreConnection(pika.ConnectionParameters(
        host='localhost'))
channel = connection.channel()

print ' [*] Waiting for messages. To exit press CTRL+C'

def callback(ch, method, properties, body):
    print body,
    sys.stdout.flush()

channel.basic_consume(callback,
                      queue='my-queue',
                      no_ack=True)

pika.asyncore_loop()

But nothing happens.

Another thing (possibly related?) that I run into is if I create a queue in
python using, e.g.:

channel.queue_declare(queue='hello')

Then, in node.js, when I do:

  var q = connection.queue('hello');

I get this:

Unhandled channel error: PRECONDITION_FAILED - parameters for queue 'hello'
in vhost '/' not equivalent

events:12
        throw arguments[1];
                       ^
Error: PRECONDITION_FAILED - parameters for queue 'hello' in vhost '/' not
equivalent
    at Queue._onMethod
(/Users/dtenenba/dev/dev-amqp/node-amqp/amqp.js:1390:15)
    at Connection._onMethod
(/Users/dtenenba/dev/dev-amqp/node-amqp/amqp.js:784:28)
    at AMQPParser.onMethod
(/Users/dtenenba/dev/dev-amqp/node-amqp/amqp.js:698:12)
    at AMQPParser._parseMethodFrame
(/Users/dtenenba/dev/dev-amqp/node-amqp/amqp.js:415:10)
    at AMQPParser.execute
(/Users/dtenenba/dev/dev-amqp/node-amqp/amqp.js:196:20)
    at Connection.<anonymous>
(/Users/dtenenba/dev/dev-amqp/node-amqp/amqp.js:731:12)
    at Connection.emit (events:31:17)
    at IOWatcher.callback (net:489:16)
    at node.js:773:9

It appears that python's idea of a 'hello' queue is different from that of
node.amqp's. How can I do this so that I don't receive this error?
Hope this is the right place for this question. If not please tell me where
I should post it.
Thanks
Dan
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