Convert adapters to Python

[evacchi]

While setting up CI on GHA for wazero to run against the test suite, we realized that the Python script is assuming a Unix environment. I am opening this PR to start a discussion on the best approach. In my own tests, this worked reliably.

This PR:

1. allows colorama>=0.4.3, otherwise pip on Windows (GHA windows-2022) raises the error:

INFO: pip is looking at multiple versions of colorama to determine which version is compatible with other requirements. This could take a while.
ERROR: Cannot install -r requirements/dev.txt (line 4) and colorama==0.4.3 because these package versions have conflicting dependencies.

The conflict is caused by:
    The user requested colorama==0.4.3
    pylint 2.14.3 depends on colorama>=0.4.5; sys_platform == "win32"

2. converts the shell-based adapters to Python and invokes them through the current Python interpreter (in a new sub-process)

3. updates docs and GitHub actions accordingly

(Originally proposed changes – no longer apply)

2. we explicitly invoke the shell adapter through `bash` instead of relying on the `#!` directive, because on Windows that won't work. Of course this also means that all adapters would be now expected to be runnable on bash.

4. as a further degree of complexity, it looks like proper bash (installed under C:\Program Files\Git\bin is not on the PATH when invoked from Python on GHA, invoking instead C:\Windows\system32\bash.exe which is just a stub that prints a message telling the user to install WSL (which of course we don't want as that's a virtualized linux distro).

Instead of fiddling with PATH, I decided to export an env variable (TEST_SHELL_RUNNER), which defaults to bash that can be overridden to a full path to a shell executable.

EDIT: minimal reproducer https://github.com/evacchi/gha-playground/actions/runs/4013516139/jobs/6892946727

EDIT2: I found a better workaround actions/runner-images#1081 (comment)

Signed-off-by: Edoardo Vacchi evacchi@users.noreply.github.com

[loganek]

Thanks a lot for the change. I do understand the motivation and I think it makes sense for Github Workflow. However, this change adds a requirement that all the adapters now have to be bash scripts. I'd rather avoid that unless it's absolutely necessary. Could we potentially solve it in a way so it doesn't force adapter maintainers to only write bash scripts?

[evacchi]

Obviously fair point. I have thought of two possible solutions. Neither is great 😅

1. parse the shebang. Kind of a hack. Moreover either we expect the shebang to be of the form

    !#bash
   

i.e. a bare executable without leading path, or we'll also need to parse the path (of course /bin/sh won't make any sense on windows)

2. add a tiny config file next to the adapter. While this feels less hackish it is basically reproducing the shebang, including the path issue

While I would favor (2) it's only slightly less of a hack

[codefromthecrypt]

PS after this change, there's still a problem with the shell scripts (at least in git bash). For example, assemblyscript environ_get-multiple-variables fails when run in anything including wasmtime due to the parse arg loop not handling newlines properly.

It may be a better choice to not use bash and also python, rather just python? In other words maybe we can avoid the whole fork bash problems by not using it and instead have the shims python?

$ python3 test-runner/wasi_test_runner.py -t ./tests/assemblyscript/testsuite/ -r adapters/wasmtime.sh
--snip--
Test environ_get-multiple-variables failed
  [exit_code] 0 == 1
STDOUT
Unknown option line
--snip--

[evacchi]

using Python would seem fair to me. After all the adapters are pretty simple

[loganek]

I'd be ok with using Python as adapter, given it's very simple and we already require it for runtime anyway. @evacchi would you like to update your PR to support Python for adapters?

[evacchi]

I'd be ok with using Python as adapter, given it's very simple and we already require it for runtime anyway. @evacchi would you like to update your PR to support Python for adapters?

so translate the other adapters? sure that's doable if you're ok with it :)

[evacchi]

I have added another commit (we can close/squash/whatever the PR in case this looks good) to run python-based adapters.

[loganek]

Thanks a lot, the change looks good to me. I left a few minor comments. i think we should also delete bash adapters once we have python ones too.

I think we should also update the documentation and and CI jobs. Please let me know if you can help with those as well.

[evacchi]

Wonderful, sure will look into that too. In the meantime I am also making super sure everything works as expected

[evacchi]

I think I have applied the changes you suggested; obviously feel free to add more comments :) in case all is good, feel also free to squash the PR and merge (unless we want me to rebase and squash explicitly)

Thanks!

[loganek]

The change looks good. I don't know of any other runtime that implements the adapter (other than toywasm, which already is written in Python), so I think we can merge it now.

Many thanks for making the change!