Bing's Blog

Daemonizing with Upstart

Recently I've been trying to use IPython notebooks more while doing research. Since the notebook server needs to be started before you can use the awesomeness of IPython notebooks, I decided to try to find a method to automatically start my notebook server when I login.

Since I do most of my development on Ubuntu, one obvious choice was Upstart. The 'Getting Started' page pointed me to the cookbook, which I read through. I found the cookbook to be less of a cookbook, and more of a comprehensive reference for all the commands, which made it a little hard to get started. One thing that wasn't explained in the cookbook was how to enable session init management. However, I found a helpful page here which explained how to enable Upstart user sessions.

After some experimentation, I was able to get the following conf file working:

# Job configuration for IPython Notebook
description "IPython Notebook"

stop on runlevel[06]

respawn
respawn limit 10 5 # respawn up to 10 times, waiting 5 seconds each time

pre-start script
    [ ! -f $HOME/.virtualenvs/molpy3/bin/activate ] && { stop; exit 0; }

    . $HOME/.virtualenvs/molpy3/bin/activate
end script

exec $HOME/.virtualenvs/molpy3/bin/ipython3 notebook --profile=nbserver

This file should be placed in $HOME/.config/upstart with a .conf extension.

While I was playing with Upstart, I also decided to daemonize my emacs. I already use emacs --daemon on my machine almost exclusively, but it would be nice for the emacs server to start automatically and be killed in a nice manner (saving unsaved files) on shutdown. The script for daemonizing emacs looks very similar, except that I have a pre-stop block which uses emacsclient to call (save-some-buffers t) before emacs is killed.

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