Preparing a complex python project for submission to launchpad

Question

I'm trying to wrap my head around the whole PPA thing and it seems to be as unnecessarily difficult as everybody is making it out to be. Let's take a project like http://docs.bokeh.org/ which has a node.js dependency and make a .deb out of it. Following this guide, and various posts here, I tried to use stdeb to do it:

pypi-download bokeh
tar xfz bokeh-0.7.0.tar.gz
cd bokeh-0.7.0/bokehjs/
npm install
grunt build
cd ..
python3 setup.py --command-packages=stdeb.command sdist_dsc

The end of the output is

dh clean --with python3 --buildsystem=python_distutils
   dh_testdir -O--buildsystem=python_distutils
   debian/rules override_dh_auto_clean
make[1]: Entering directory `/home/emre/Desktop/bokeh-0.7.0/deb_dist/bokeh-0.7.0'
python3 setup.py clean -a
/home/emre/Desktop/bokeh-0.7.0/deb_dist/bokeh-0.7.0/bokehjs

ERROR: Cannot install BokehJS: files missing in `./bokehjs/build`.


Please build BokehJS by running setup.py with the `--build_js` option.
  Dev Guide: http://docs.bokeh.org/docs/dev_guide.html.

I just did that! Am I missing something? Is this building even necessary for something that's straight off pypi? The guides gloss over these things.

Answer 1

Making good debs can be complicated, yes, especially when you are not the upstream author and aren't sure exactly what their intentions were for installations of their software. The complication is necessary because well-behaved debs must conform to a fairly long list of policies and requirements so that users know what to expect from them in many different situations and cases. Source for debs needs to contain enough information that it can be built by automated systems (including installing any necessary build dependencies). Binary (built) debs must put their files in the right places on the system and not break any other packages and be able to clean up after themselves fully on uninstall. Debs should be installable without a user watching on an interactive terminal. Debs must declare all of their dependencies, and necessary versions of those dependencies, except for a few packages considered "required". Debs should not download anything from the internet during build or install. And so on, and so on. This strictness and the degree to which the community adheres to it is actually one of the most important benefits of running a Debian-based distribution.

Python source distributions such as those you find on PyPI, on the other hand, can pretty much do whatever they want. There are emerging best-practices for build and install commands with setup.py, but they're not always followed, and even when they are, there is still a lot of room for interpretation and variance. Some, such as the one you reference here, might arbitrarily require the user to call setup.py with a different nonstandard option before building normally. Some go ahead and download their own dependencies and put them wherever they want. Most packages beyond the trivial don't know how to uninstall themselves.

Both approaches are fine and are better in different contexts. But hopefully you can see now why it's not possible in the general case to make arbitrary Python source distributions automatically into working debs. There is just too much that the computer has to assume about how the Python will behave.

Having said all that, if you don't care about conforming to Ubuntu/Debian policy and you just want to be able to put something in a personal repository, the easiest path for you might be to change the Python source so that it does its --build_js thing automatically as necessary, rather than complaining and asking the user to do it.