Manage RabbitMQ consumers - symfony

Question

I am planning to write a log processing application using RabbitMQ, Symfony2 and the RabbitMqBundle.
The tool I am working on has to be highly available and must process millions of entries per day, so it's important that the consumers are always up and running (short breaks are fine), otherwise my queue might overflow after a while.
Are there best practices on how to manage the consumers (written in PHP), start/restart them in case of an error etc?
Thanks

Answer 1

I use this bash script to make sure that there are all required consumers running on imagepush.to:
#!/bin/bash
NB_TASKS=1
SYMFONY_ENV="prod"
TEXT[0]="app/console rabbitmq:consumer primary"
TEXT[1]="app/console rabbitmq:consumer secondary"
for text in "${TEXT[#]}"
do
NB_LAUNCHED=$(ps ax | grep "$text" | grep -v grep | wc -l)
TASK="/usr/bin/env php ${text} --env=${SYMFONY_ENV}"
for (( i=${NB_LAUNCHED}; i<${NB_TASKS}; i++ ))
do
echo "$(date +%c) - Launching a new consumer"
nohup $TASK &
done
done
If I remember correctly I took base from KnpBundles code.

Answer 2

Stop consumer
To stop your consumer with name my_consumer use
kill `ps aux | less | grep 'rabbitmq:consumer my_consumer' | grep -v grep | awk '{print $2}'`
ps aux | less | grep 'rabbitmq:consumer my_consumer' - will find all running processes of the consumer
grep -v grep - will exclude your own search process
awk '{print $2}' - get only process id from the row
kill - will terminate all found processes
Start consumer
To start your consumer with name my_consumer use
nohup /usr/bin/env php app/console rabbitmq:consumer consumer --env=prod &
I have a lot of consumers in the project and it became hard to restart them after deploy. And I started using Capistrano + Symfony plugin to deploy my project. I wrote a few custom tasks to start/stop/restart the consumers based on the yaml config. Tasks are based on the commands from above.