I have a Javascript action that executes Python. It would be great if I could add @actions/setup-python as a dependency and call it from my Javascript action.

In order to make it work for now I converted parts of this action into a setupPython function that I've included with my action. Below is a simplified snippet of what I'm doing now. Full source code here.

async function run() {
  try {
    const src = __dirname + "/src";

    // Setup Python from the tool cache
    setupPython("3.8.0", "x64");

    // Install requirements
    await exec.exec("pip", [
      "install",
      "--requirement",
      `${src}/requirements.txt`
    ]);

    // Execute python script
    await exec.exec("python", [`${src}/create-pull-request.py`]);
  } catch (error) {
    core.setFailed(error.message);
  }
}

Here is a python-action template that also demonstrates what I'm doing in the snippet above.

Why call Python from a Javascript action?
The reason I ended up doing this and not writing the whole action in Javascript requires a bit of history and explanation. I wrote the action during GitHub Actions beta v1 when it was just container actions. When Actions v2 arrived the choices were Javascript or Docker container actions. I want the action to be multi-platform and runnable on any virtual machine, so I have no choice but to wrap it with a Javascript action as I'm doing, or convert the whole action to Javascript.

Even if Docker container actions worked on all platforms I think I would still choose to wrap Python in Javascript like this. The two issues I don't like about container actions are:

• When using image: 'Dockerfile' it's slow because the image is built from scratch every time the workflow runs.
• When using image: 'docker://my-namespace/my-image:1.0.0' it cannot be forked easily because the reference to the public Docker image remains. Being able to fork GitHub actions is important for security conscious users.