Programmatically generate requirements.txt file

Question

I'm trying to generate a requirements.txt file programatically. This way I can diff it against a second .txt file. So far I've tried the following, but they only output the requirements to console (No .txt file is generated).

So far I've tried

    import pip

    pip.main(["freeze",">","requirements.txt"])

and

    from subprocess import call

    call(["pip","freeze", ">","requirements.txt"])

If I attempt to run the same command manually in terminal though, the file is generated without issue. Any suggestions?

Answer 1

Ask pip to directly provide the list of distributions

Script myfreeze.py

import pip
with open("requirements.txt", "w") as f:
    for dist in pip.get_installed_distributions():
        req = dist.as_requirement()
        f.write(str(req) + "\n")

Then you get expected content in your requirements.txt file.

Answer 2

subprocess.Popen(['pip', 'freeze'], stdout=open('/tmp/pip.log', 'w'))