cron tab to restart my delayed_job server

Question

I want to create a cront tab to restart my delayed_job server if it breaks.

how may check that my delayed_job server is running or not with ps command?

how may i create a cron tab to check this thing work? Like if my server break than cron tab will restart it. I want to set cront tab to check it every 5 minute.

Answer 1

This is my script which check if pid files is created or not. If pid file is not exist than it will start the delayed_job server. I have created my script in my application root folder This is my script delayed_job.sh

if ! [ -s delayed_job.pids ]; then
  RAILS_ENV=production /app/script/delayed_job start
end

And i have set this script on crontab like this.

*/5 * * * * RAILS_ENV=production /bin/bash /app/delayed_job.sh

It's working fine. If i break delayed_job server than it will automatically start my delayed_job server. Is it a proper way??

Answer 2

The right way if you have one delayed_job process is:

#!/bin/bash

if ! [ -s #{pids_dir}/delayed_job.pid ]; then  
  RAILS_ENV=production #{RAILS_APP}/script/delayed_job start  
fi

Answer 3

I use runit/sv to manage delayed_job. Includes monitoring, auto restarts, logging.

Answer 4

If you don't stick to cron, Monit may be more useful. http://mmonit.com/monit/

Answer 5

Here's my solution. I check for whether you have a single job started or you have more than one. If you do, quit, otherwise start the job with two workers. You probably won't need that /usr/local/bin/ruby part.

#!/bin/bash

if [[ ! -f /apps/gits/myapp/tmp/pids/delayed_job.pid 
      && ! -f /apps/gits/myapp/tmp/pids/delayed_job.0.pid ]];
then
  echo "DJ not running" 
  cd /apps/gits/myapp
  RAILS_ENV=production /usr/local/bin/ruby script/delayed_job -n 2 start
  echo "DJ Started"
else
  echo "DJ running"
fi

And then my cron runs every hour, just make sure the bash is executable.

0 */1 * * * /apps/gits/scripts/start_dj_if_not_running.sh 
               >> /apps/gits/myapp/log/runner.log 2>&1