Updating live server from VCS

Question

I run all my Django sites as SCGI daemons. I won't get into the fundamentals of why I do this but this means that when a site is running, there is a set of processes running from the following command:

/websites/website-name/manage.py runfcgi method=threaded host=127.0.0.1 port=3036 protocol=scgi

All is fine until I want to roll out a new release from the VCS (Bazaar in my case). I made an alias script called up that does the following:

alias up='bzr up; killall manage.py'

It is this generic for one simple reason: I'm lazy. I want one command that I can use under any site to update it. I'm logged into the server most of the time anyway, so, I just hop into the root of the right site and call up . Site updates from BZR and restarts.

The first downside of this is it kills all the manage.py processes on the machine. Currently 6 sites and growing rapidly. The second (and potentially worse -- at least for end-users) is it's a severely non-graceful restart. If somebody was uploading an image or doing something else with a long connection time, their request would just die on the vine.

So what I'm looking for is suggestions for a single method that:

1. Is generic for lazy people like me (eg I can run it from any site root without having to remember which command I need to call; 'up' is perfect in name.
2. Only kills the current site. I'm only updating the current site, so only this one should die.
3. Does the restart in a graceful manner. If possible, it should wait until there are no more active connections. I've no idea how feasible this is.

Answer 1

Instead of killing everything with manage.py in the name, could you write a script for each site that only kills manage.py processes from that site? (Edit: just write the scripts and put them in the root of each site (which you cd to anyway) and run those – still only one command to remember)

I don't know enough about SCGI or Bazaar to suggest much more than that... My method (I'm lazy too) uses Mercurial and Fabric for deployment: http://stevelosh.com/blog/entry/2009/1/15/deploying-site-fabric-and-mercurial/ – maybe it will give you an idea you can use?