command not found (in image node:12.6-buster-slim, as opposed to GH Actions)

[fwilhe]

Hi,

as documented here GitHub configures passwordless sudo, so I can have sudo in my shell scripts to perform individual commands as root.

Given this minimal workflow:

on: push
name: Test
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
    - run: sudo id

The result on Actions is uid=0(root) gid=0(root) groups=0(root)

Running this workflow in act yields this result:

$ act
[Test/build] 🚀  Start image=node:12.6-buster-slim
[Test/build]   🐳  docker run image=node:12.6-buster-slim entrypoint=["/usr/bin/tail" "-f" "/dev/null"] cmd=[]
[Test/build]   🐳  docker cp src=/Users/fwilhe/temp/test-actions/. dst=/github/workspace
[Test/build] ⭐  Run sudo id
| /github/workflow/0: line 2: sudo: command not found
[Test/build]   ❌  Failure - sudo id
Error: exit with `FAILURE`: 127

Not sure what the most elegant solution would be without re-building the node:12.6-buster-slim image to install sudo and configure it passwordless. But I think the goal should be to be 1:1 compatible with actions, if possible.

[cplee]

See https://github.com/nektos/act#runners.

You can customize the image used for the runs-on. I've created an image that is a match to GitHub runners, but its like 15GB!

[fwilhe]

Hi @cplee

thanks for the work you put into this.

I know that the image is configurable, and I've locally tested with an image where I installed sudo. So this is kind of a workaround, but the reason I opened this issue is that this limits compatibility with workflows that run on GitHub. My intention was to point out where the documented (and actual) behavior of Actions is unequal the default of act, which makes it less useful compared to what it could be.

As mentioned I'm not sure what solution I would propose, as maintaining separate images seems inappropriate.

[cplee]

Tough problem. The runners that GitHub Actions offers are huge. I didn't feel right using an 18GB image as the default, requiring users of act to download that large of an image to run it.

I chose the node image because it was required to run node actions and still light enough. Not sure how to proceed...not sure what good enough looks like for the default docker image.

Open to ideas 🙏

[aidansteele]

I wonder if there's a way we could make an intermediary image that has 90% of the needed CLI tools for 10% of the footprint of the giant image. The only way we could reasonably do that (beyond intuition) is scanning a corpus of public GH Actions and seeing what works.

Then again, maybe it would give people a false sense of security as these issues would crop up less often - so it would be "stranger" and more likely to result in bug reports. 🤔

[aniongithub]

Maybe act could use a .Dockerfile that the user can customize to make sure whatever tools they need is available in the used image. This could live in ~/.act/ or the current project directory?