我应该用我的Python应用程序捆绑C库吗？

Question

If I have a Python package that depends on some C libraries (like say the Gnu Scientific Library (GSL) for numerical computations), is it a good idea to bundle the library with my code?

I'd like to make my package as easy to install as possible for users and I don't want them to have to download C libraries by hand and supply include-paths. Also I could always ensure that the version of the library that I ship is compatible with my code.

However, is it possible that there are clashes if the user has the library installed already, or ar there any other reasons why I shouldn't do this?

I know that I can make it easier for users by just providing a binary distribution, but I'd like to avoid having to maintain binary distributions for all possible OSs. So, I'd like to stick to a source distribution, but for the user (who proudly owns a C compiler) installation should be as easy as python setup.py install .

Answer 1

Distribution is one of the hard parts for any software project. Java and .NET lift part of this burden by defining a standard runtime and then just saying "just distribute everything else." Of course there's a drawback: everything must be rewritten in a language supported by the runtime - as soon as you want to use native code, you lose all the advantages.

That's harder in Python, as it is in Ruby, C, C++ and other languages, as they usually leverage existing native libraries.

Generally speaking:

1. Make it possible to get a source sdist, via pypi.python.org as an example. Correctly set your install_requires (probably you'll require python bindings for GSL, not GSL itself). Use standard setuptools/distribute layout. This will let anyone - let's say a package maintainer for any distro - to pick up your software and package it.

2. Additionally, consider providing a full-blown installable package for your audience. You don't have to support all the distros and operating system; pick one or two that you consider will be used most. Tools like PyInstaller will let you create an installable, runnable package for many operating systems, but especially for linux you might want the user to install the distribution's own version of transitive deps (libgsl?) - you'll need a full-blown deb or rpm package to satisfy that - again, don't try supporting any and all the distro, you'll turn out mad. Support something you most use, and let other users to help you with other packaging needs.

Also take a look at Python Packaging Guide

Answer 2

You could have two separate branches of the src, one containing the libraries and another that doesn't. That way you can explicitly warn your users in case they have installed the libraries. Another solution could be (if the licences of the libraries allow you) is to wrap 'em up in a single file.

I think there's no unique solution, but this are the ideas I could think so far.

Good luck

Answer 3

You can use virtualenv to create a private Python environment for your application. This avoids conflicts with other libraries. It is best if you package modules and dependencies such as your libraries using Distribute . Distutils is something else that is worth researching.