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?

Jan Vlcinsky · Accepted Answer · 2014-06-20 08:03:19Z

8

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.

edited Jun 20, 2014 at 8:03

answered Jun 20, 2014 at 7:51

Jan Vlcinsky

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Shuo · Accepted Answer · 2014-06-20 07:44:29Z

4

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

answered Jun 20, 2014 at 7:44

Shuo

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GuillemB · Accepted Answer · 2023-04-30 19:41:42Z

3

Using pip for this is strongly discouraged by the developers of pip. It is also broken in more recent versions of pip. Here is a summary of the approach suggested on the linked Github issue. Very similar to the accepted answer but using the pkg_resources module instead.

import pkg_resources


def generate_pip_freeze() -> str:
    requirements = ""
    for dist in pkg_resources.working_set:
        req = dist.as_requirement()
        requirements += f"{req}\n"
    return requirements

or more succintly:

def generate_pip_freeze() -> str:
    return "\n".join(
        str(dist.as_requirement()) for dist in pkg_resources.working_set
    )

edited Apr 30, 2023 at 19:41

answered Oct 21, 2021 at 7:36

GuillemB

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Jake Stevens-Haas · Accepted Answer · 2023-12-10 10:24:46Z

2

Now that pkg_resources is deprecated, you should do this with importlib.metadata (or importlib_metadata, its backport to earlier Python versions)

from importlib.metadata import packages_distributions, version
  
installed = {pkg for pkgs in packages_distributions().values() for pkg in pkgs}
req_str ="\n".join(f"{pkg}=='{version(pkg)}'" for pkg in installed)

with open("requirements.txt", "w") as f:
        f.write(req_str)

edited Dec 10, 2023 at 10:24

answered Dec 7, 2023 at 16:29

Jake Stevens-Haas

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1 Comment

Eric L. Over a year ago

the single quotes around the version aren't accepted by pip if used with pip install -r requirements.txt, they should be removed.

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Programmatically generate requirements.txt file

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Ask pip to directly provide the list of distributions

Script `myfreeze.py`

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Ask pip to directly provide the list of distributions

Script myfreeze.py

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Script `myfreeze.py`