Programmatically check if Python dependencies are satisfied

Question

I'd like to programmatically run pip and determine whether the current virtualenv environment complies with a specified requirements.txt file. I'm not fussed about running pip or anything, but I thought since it can read requirements.txt-like files, it would be a good start.

However, I haven't even found a way of effectively running pip from the command line. pip install -r requirements.txt --no-install was suggested somewhere, but it downloads each package and even if this wasn't a problem, I am unsure of how to interpret its output as to whether or not all dependencies are satisfied.

Answer 1

This post has a lot of good suggestions for getting a list of modules. You can use the below code to print out all missing modules:

from pkgutil import iter_modules
modules = set(x[1] for x in iter_modules())

with open('requirements.txt', 'rb') as f:
    for line in f:
        requirement = line.rstrip()
        if not requirement in modules:
            print requirement