connect() calls its own callback multiple times upon error

[dotkas]

Hello.

If I try to connect to a queue using invalid credentials, such as this:

amqp.connect(config.endpoints.textQueue + '?heartbeat=30', (err, conn) => {
    if (err) {
        return callback(`Unable to connect to rabbitMQ (${url.parse(config.endpoints.textQueue).host}), is there a connection? Aborting: ${err}`);
    }
(...)
}

The callback is called two times with an err parameter. First one that gives me access denied, and then one with a socket close.

This obviously causes my code to throw an exception due to the callback already having been called.

Is this working as intended?

First callback:
Handshake terminated by server: 403 (ACCESS-REFUSED) with message \"ACCESS_REFUSED - Login was refused using authentication mechanism PLAIN. For details see the broker logfile.\"

Second:
Socket closed abruptly during opening handshake

Thank you in advance.

[cressie176]

I get the same. Looks like a bug. Could be fixed by wrapping openCallback so that it only ever is executed once, or by checking / setting a flag wherever openCallback is called, however both of these solutions would mean suppressing socket errors that occurred after successfully connecting. @squaremo thoughts?

[cressie176]

I suspect this is the root cause of onebeyond/rascal#17

[tcort]

I ran into this issue as well. As a work around, I used _.once(fn) to wrap the callback I passed to amqp.connect() as described here: onebeyond/rascal#17 (comment)

[cressie176]

This seems better in 0.5.2, however I'm I've just hit a similar problem with errors returned from connection.createChannel.

Steps to reproduce

1. Create Connection
2. Create Channel
3. Subscribe (without optional callback)
4. Close connection

If the subscription hasn't complete by the time the connection is closed, amqplib executes the create channel callback multiple times.

[AbdulRahmanAlHamali]

This bug, combined with the retry code presented here:

https://www.cloudamqp.com/docs/nodejs.html

Can DDoS RabbitMQ. It's a shame it hasn't been addressed yet

[cressie176]

Duplicate of #402