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A wrapper around gunicorn to handle graceful restarts correctly

Project description

Rainbow Saddle

rainbow-saddle is a wrapper around Gunicorn to simplify code reloading without dropping requests.


Install from pypi:

$ sudo pip install rainbow-saddle

Or from source:

$ sudo ./ install


Sometimes doing a kill -HUP <gunicorn PID> is not sufficient to reload your code. For example it doesn’t work well if you host your code behind a symlink, or if a .pth in your installation is updated to point to a different directory.

The correct way to reload code in such situations is a bit complicated:

# Reexec a new master with new workers
/bin/kill -s USR2 `cat "$PID"`
# Graceful stop old workers
/bin/kill -s WINCH `cat "$PIDOLD"`
# Graceful stop old master
/bin/kill -s QUIT `cat "$PIDOLD"`

It also has the downside of changing the “master” process PID, which confuses tools such as supervisord.

rainbow-saddle handles all of this for you, and never changes its PID. Reloading code becomes as simple as sending a SIGHUP again:

$ rainbow-saddle --pid /tmp/ gunicorn_paster development.ini --log-level debug
$ kill -HUP `cat /tmp/`



Support new binary upgrade method used by Gunicorn, since version 19.6.0. Drops support for all previous versions of Gunicorn. See commit benoitc/gunicorn@418f140 for more info, thanks to Jacob Magnusson.


Minor Python3 compatibility fix, thanks to Justin Locsei.


Thanks to Rafael Floriano da Silva for the following:

  • add –gunicorn-pidfile

  • fix race condition for slow starting apps

  • update psutil

Project details

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rainbow-saddle-0.4.0.tar.gz (5.2 kB view hashes)

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