changeset 79:a599feff7c93

moving the cheeseshop document here; not the best place but it will work for now
author Jeff Hammel <jhammel@mozilla.com>
date Mon, 21 Jun 2010 13:16:24 -0700
parents 84ffa220796a
children 413945f4c18b
files python/cheeseshop.txt
diffstat 1 files changed, 103 insertions(+), 0 deletions(-) [+]
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+++ b/python/cheeseshop.txt	Mon Jun 21 13:16:24 2010 -0700
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+Making your own cheeseshop
+
+It is a common misconception that the cheeseshop (pypi.python.org) is
+*the* place to go for python packages.  This is only true by
+convention.  I won't go into the history of
+distutils/setuptools/distribute/pip packaging fiasco.  Suffice it to
+say that (I hope) things are slowly converging and that both pip and
+easy_install, the two major ways of installing python software, both
+support a -i option to specify the URL of the package index (which is,
+by default http://pypi.python.org/simple).
+
+In its base form, easy_install and pip just crawl links.  You look at
+the base URL (see above) /<package>/<package>-<version>-<extension>
+and download this, unzip, run `python setup.py install` on it and
+you're done.  So if you want to make a cheeseshop, there are two
+essential tasks:
+
+ 1. Generating e.g. tarballs for a package and all of its dependencies
+ 2. Putting these tarballs on the web with some appropriate parent
+    directory
+
+Not rocket science...barely computer science, really.
+
+For generating packages and their dependencies, I used pip.  pip is
+really great for this.  I only used the command line interface, though
+if I was smarter, I probably should have looked at the API and figured
+out what pip is doing internally and I could have avoided a few
+steps.  Basically, using the --no-install option downloads the package
+and its dependencies for you and lets you do what you want with it. 
+
+I made a program for this, see http://k0s.org/hg/stampit . It's a
+python package, but it doesn't really do anything python-y.  It was
+just easier to write than a shell script for my purposes.  Basically
+it makes a virtualenv (probably overkill already), downloads the
+packages and their dependencies into it, runs `python setup.py sdist`
+on each package so that you have a source distribution, and prints out
+the location of each tarball.
+
+The source distribution is very important as we want packages that
+will work independent of platform.  These should.  If they don't, we
+can make them.
+
+So problem #1 solved.  Let's move on to problem #2: putting them
+somewhere on the web.
+
+Mozilla is so kind as to have given me a URL space on
+people.mozilla.org. Since easy_install and pip are really dumb and
+basically just crawl links, and since Apache is smart enough to
+generate index pages for directories that don't have index.html files
+in them, the hard part is already solved.  I will note that
+people.mozilla.org is not intended as a permanant place for these
+tarballs, just an interim instance until we decide where we really
+want to put them.
+
+Since I like to write scripts, I wrote a script that will run stampit
+and copy the resulting tarballs to a place appropriate to a
+cheeseshop.  You can see the code here:
+
+http://k0s.org/mozilla/package-it.sh
+
+The variables are pretty specialized to my setup, but of course that's fixable.
+
+Does it really work?
+
+Yes!  You can try it for yourself. Try:
+
+``easy_install -i http://people.mozilla.org/~jhammel/packages/ mozmill``
+
+Watch where the links come from.  Surprise!  They're all from
+http://people.mozilla.org/~jhammel/packages/ !
+I would *highly advise* doing this (and just about everything else in
+python) in a virtualenv so that you don't pollute your global
+site-packages.
+
+Why am I doing this?
+
+The Firefox buildslaves are supposed to fetch data only from mozilla
+URLs for stability.  So, if python packages need to be installed, they
+need to be available internal to Mozilla.  If a package didn't have
+dependencies, then this is a no-brainer.  But packages do have
+dependencies. Mozmill depends jsbridge, simplejson, and mozrunner.
+While this is a lot of work for just one package, if we want more
+python stuff in our buildbot tests, we'll need to do more of this, and
+I'd rather have a good solid methodology to do so.  I also imagine
+this growing as a place to put all of our python packages for internal
+Mozilla needs.
+
+I will note that I did this in a few hours from basically knowing the
+problem space but never having actually done it.  None of this is
+supposed to be a clean and polished solution.  But really, its not
+bad.  We did something similar but less functional at my last job, The
+Open Planning Project, for similar reasons, so its not like I tackled
+this blindly. This is not as fully functional as the cheeseshop.  A maintainer
+needs to run the package-it.sh script for each package (and its deps)
+they want installed.  There's no accounts or any of the other features
+the cheeseshop has.  But for a simple prototype and a way to move the
+discussion forward, its actually not that bad of a solution.  There
+are more robust ways of really doing the cheeseshop, such as
+http://github.com/ask/chishop , but for a package dumping ground, this
+solution works and its really not even that hacky (in my opinion
+anyway).
+
+