pcntl signals processed only after message is handled

[richardfullmer]

Hey @videlalvaro,

Great bundle. We use it in many of our projects.

Recently, we've had some issues with one of our consumers that doesn't receive messages that often. 1 per 30 minutes or so.

The issue we have is with handling the pcntl signals. Presently, handling signals happens after the next message is processed. When your script is processing messages at a rate of 1 per second, sending a SIGINT will only have you waiting 1 second before it's handled properly.

Now, in the case of 1 per 30 minutes, this is obviously a problem. We're specifically having the issue during deploys. We want to restart all consumers each deploy. Waiting 30 minutes really isn't an option.

Is there a way to have the following happen?

• If a signal arrives while the consumer is waiting for the message, it just handles it immediately and close down.
• If a signal arrives during the processing of one of these messages, it obviously should finish handling the message first, then handle the signal and close down.

I tried playing around with the bundle and the underlying lib, but the architecture seems to make this hard to accomplish.

Any ideas? I'm happy to write the code if there's a good solution without a ton of refactoring.

[videlalvaro]

$ch->wait() now accepts a timeout parameter, maybe it can help with your use case: https://github.com/videlalvaro/php-amqplib/blob/master/PhpAmqpLib/Channel/AbstractChannel.php#L174

[videlalvaro]

@richardfullmer any progress here?

[richardfullmer]

I tried using the timeout parameter but it didn't fix my issue. We're doing a manual process of kill -9'ing the consumer now instead of sending it a signal. Dangerous, but it's working for us.

I plan to return to this issue when less pressing matters are behind me.

[dmikhinev]

Hi @videlalvaro. I got same problem.
I have idea to put dispatching of pcntl signal to PhpAmqpLib\Channel\AbstractChannel::wait just after while(true) like in RabbitMq\BaseConsumer::maybeStopConsumer

[videlalvaro]

do you think this would affect performance?

[dmikhinev]

I don't know..
But current way is hard to use in CI environment because consumer can't be updated normally for rarely used queue. I see issue around blocking read from socked and found solution for non-blocking read in php-amqplib doc but can't understand how to implement same with RabbitmqBundle.