patch a `pip_install`

[knzivid]

🚀 feature request

Relevant Rules

pip_install

Description

I want to patch a python package after it is installed.

Describe the solution you'd like

Similar to patches argument in http_archive, I would like an extra argument in pip_install.

Describe alternatives you've considered

• extra_pip_args argument - I did not find a way to request pip to patch a package
• Forking upstream with my tiny patch - I am open to workarounds but this is my last resort

Potential problems

• pyc files will be invalidated

[hrfuller]

Hey @knzivid Have you considered writing a small shim library which consumes the pip requirement you need and depending on that in your repository instead?

[knzivid]

The python file I intend to patch is not a part of the public interface. By a shim, do you mean a wrapper that calls this python module, but with my customizations?

[thundergolfer]

Yes, I think Henry means basically that. I think wouldn't work well though if you wish that all packages in your target's transitive closer see the customization, as they of course wouldn't import the wrapper.

[UebelAndre]

I've been able to modify the package_annotation functionality (from #589) to add some patching support to whl_library but the patching applies after the wheel is installed. I think it'd be ideal to patch before but I'm not sure how to go about setting up an extracted wheel. Any suggestions or opinions there?

edit:
The reason it'd be nice to patch a wheel before installing it would be to modify setup.py and avoid having python even attempt to do things like compile some C++ source.

[philsc]

@UebelAndre , do you have a PR for your wheel patches via annotations? If not, I have an internal patch that I can clean up and put up a PR. My internal patch also works with annotations post build. I don't know how one would implement pre-build patches because it would require intercepting pip. Also, we don't have any use cases for it at the moment.

[groodt]

I prefer a user-space solution, similar to this in the JVM ecosystem:
https://github.com/johnynek/bazel_jar_jar

I believe it's entirely reasonable to want to patch wheels (and possibly sdist), but Im not really a massive fan of the present "annotation" approach. Is there a way to create this functionality without using the annotations?

[UebelAndre]

I prefer a user-space solution, similar to this in the JVM ecosystem: https://github.com/johnynek/bazel_jar_jar

I believe it's entirely reasonable to want to patch wheels (and possibly sdist), but Im not really a massive fan of the present "annotation" approach. Is there a way to create this functionality without using the annotations?

Can you expand on what you don't like about the "annotation" approach and what "bazel_jar_jar" does that you prefer?

[UebelAndre]

@UebelAndre , do you have a PR for your wheel patches via annotations? I

I do not, I was able to use the new download_only feature with custom built wheels to remove the need for patching.

[creste]

I have an internal patch that I can clean up and put up a PR. My internal patch also works with annotations post build.

@philsc - That would be very helpful for me. I am also interested in patching python packages after they are built.

[philsc]

@creste , apologies for the delay. Here are the "non-cleaned-up" patches: https://github.com/frc971/971-Robot-Code/tree/master/third_party/rules_python
These patches (specifically, the second one) allow you to create a file like this: https://github.com/frc971/971-Robot-Code/blob/master/tools/python/patches.json
There you can specify the patches you care about.
You can point the WORKSPACE at the patches.json file like this: https://github.com/frc971/971-Robot-Code/blob/3eaca7e070c0b4a6909eaf6eec14ac26e5364dce/WORKSPACE#L441
(EDIT: I believe I set it up so that the values in patches.json have to be normalized: name.lower().replace("-","_").replace(".","_").)

It's not ideal, but this works for us at the moment.

I ended up abandoning the annotations approach because @groodt convinced me to avoid adding more annotations features. Instead, I am working on a proposal for a different approach. I am finding less time for that proposal than I was hoping so I don't have anything to show you, unfortunately.

[creste]

@philsc - Thank you! That is extremely helpful!

[Topher-the-Geek]

The patches above are for python_rules v0.16.1. There's been significant changes to the wheel installer since then. I think there's an easier way to go about this, especially if the source for the package is open on GitHub.

1. Fork the source of the package
2. Make your changes
3. In requirements.txt, write something like git+https://github.com/<you or your org>/<your repo>@<your tag or hash>

You're probably going to do the first 2 steps anyways to submit a PR to the source.