A better way to restart/reload Gunicorn (via Upstart) after 'git pull'ing my Django projects
Im looking for something better than sudo restart projectname every time I issue a git pull origin master, which pulls down my latest changes to a Django project. This restart command, I believe, is related to Upstart, which I use to start/top my Gunicorn server process.
This restart causes a brief outage. Users hitting the web server (nginx) will get a 500, because Gunicorn is still restarting. In fact, it seems to restart instantly, but it takes a few seconds for pages to load.
Any ideas on how to make this seamless? Ideally, I'd like to issue my git pull and Gunicorn reloads automatically.
Answer
You can tell Gunicorn to reload gracefully using the HUP signal like so:
kill -HUP <pid>
(see the FAQ for details)
I use Supervisor to control my Gunicorn server, which allows me to use this (slightly hacky) way of reloading Gunicorn after a deploy:
supervisorctl status gunicorn | sed "s/.*[pid ]\([0-9]\+\)\,.*/\1/" | xargs kill -HUP
You could obviously achieve something similar with pidof, or ps.
This is actually run from a Fabric script, so I don't even have to logon to the server at all.