Automate the gathering and publishing of new toolchain versions

[b-n]

An attempt at automatically updating the toolchain version.

In short what this PR does:

• Get the current RUST_VERSION from the Rakefile I originally though of using some grep/regex magic to get this value, but thought: "Ruby knows best what it's looking for".
• Get the latest release from rust-lang/rust (This is what github determines as "latest" - so there is some limitation there if patches for older versions are released)
• IF the values are different:
  • update the value with sed magic in the file (Makes me second guess my "ruby knows best" comment above) and runs bundle exec rake toolchain:sync
  • Create[/Update] a PR to merge.

I've had some success running this action with act, however for some reason I'm getting a "Could not read from remote repository" when it tries to run git remote prune origin here: https://github.com/peter-evans/create-pull-request/blob/main/src/create-pull-request.ts#L138. (running with act -s GITHUB_TOKEN="$(gh auth token)" -j check-toolchain-version, have also tried a hardcoded PAT token, to no success).

I can confirm everything works up until the git pr/commit part of it, so that's all good. In theory the last PR part should "Just work", but it might be a wait and see on the next rust release. I fear having a dirty tree (only easy way to test this) is causing some issue somewhere.

Fixes: #192

[b-n]

@lopopolo Woo! https://github.com/b-n/gh-action-test/blob/main/.github/workflows/create-pr.yaml generates https://github.com/b-n/gh-action-test/pull/1 so the answer is yes - we can play with variables, and yes - it works. I added you as a contributor to that repo so you can press the play button here: https://github.com/b-n/gh-action-test/actions/workflows/create-pr.yaml (if you just want to see it working :sweat_smile:

I'll fix up this PR tomorrow at some point. The key takeaways:

• It works
• It supports variable interpolation
• It does require some permissions on the action runner - I'll see if I can find the values in terraform and add to project-infrastructure if applicable.

[b-n]

w.r.t runner permissions: I can't find a terraform setting for this specific switch: https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/enabling-features-for-your-repository/managing-github-actions-settings-for-a-repository#preventing-github-actions-from-creating-or-approving-pull-requests.

Apparently it's possible to just us gh commands on github runners without having to use this particular setting (haven't tested). It seems a bit redundant though whether it's from a action or whether it's from your own gh scripting to restrict this functionality, so I'm not sure what's the best course.

The create-pull-request does use just the plain github api from what it looks. I do wonder whether providing a machine token to the token: attribute (e.g. a machine PAT token) would actually circumvent this setting. Is the one available for the artichoke org?

[b-n]

@lopopolo I have one tiny other little idea:

• Even though not "needed", we can create a rust-toolchain.toml file in this repo.
• In the rakefile, we read the current version from rust-toolchain.toml instead of inside the artichoke main repo: https://github.com/artichoke/artichoke/blob/trunk/Rakefile#L201
• We read/update the value in rust-toolchain.toml via grep/sed.

Why? Because then we can use the exact same github action in this repo as we can in the main artichoke repo. Thoughts?

Could also make it a published action. e.g.

- uses: artichoke/rust-toolchain-dependabot
  with:
    toolchain_path: ./rust-toolchain.toml
    toolchain_syntax: toml
    pre_commit_command: "bundle exec rake toolchain:sync"

"A github action that will check and update the rust toolchain. You can provide your own command to update any other files prior to commiting"

[b-n]

Sorry, another message - eventually I might try and commit a dependabot-core for rust-toolchain. Looks like an old issue is people wanting it a long time ago: https://github.com/dependabot/dependabot-core/issues/1758#issuecomment-834333421

Dependabot-core usage restricts the running of pre-post commit things, but there is apparently a way to bump commits on top of dependabot PRs, so that could be done for the toolchain:sync part: https://github.com/dependabot/dependabot-core/issues/1758#issuecomment-834333421 (This is a big TIL for me today - kinda cool :sweat_smile:)

[lopopolo]

w.r.t runner permissions: I can't find a terraform setting for this specific switch: https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/enabling-features-for-your-repository/managing-github-actions-settings-for-a-repository#preventing-github-actions-from-creating-or-approving-pull-requests.

at https://github.com/artichoke/docker-artichoke-nightly/settings/actions:

There's an org setting I can flip to enable us turning that on in this repo. Let me look to see if I can terraform this.

[lopopolo]

@lopopolo I have one tiny other little idea:

• Even though not "needed", we can create a rust-toolchain.toml file in this repo.
• In the rakefile, we read the current version from rust-toolchain.toml instead of inside the artichoke main repo: https://github.com/artichoke/artichoke/blob/trunk/Rakefile#L201
• We read/update the value in rust-toolchain.toml via grep/sed.

Why? Because then we can use the exact same github action in this repo as we can in the main artichoke repo. Thoughts?

Could also make it a published action. e.g.

- uses: artichoke/rust-toolchain-dependabot
  with:
    toolchain_path: ./rust-toolchain.toml
    toolchain_syntax: toml
    pre_commit_command: "bundle exec rake toolchain:sync"

"A github action that will check and update the rust toolchain. You can provide your own command to update any other files prior to commiting"

this sounds pretty sweet and I'd be interested to experiment here. Let me know if you want me to set up a repo for you

[b-n]

@lopopolo I'll merge this one for now after incorporating the feedback. I'm sure the action will fail on the run unless those options are action perms are added.

Also, more than happy to give a generic action a go, so yes please to a repo!

[lopopolo]

I tweaked the setting and bumped the job. It worked!

• https://github.com/artichoke/docker-artichoke-nightly/pull/198

[lopopolo]

It looks like PRs created with this workflow don't trigger github status checks to run on PRs: https://github.com/peter-evans/create-pull-request/issues/48

A workaround I've found is to close and then reopen the PR.