Jeff King <peff@xxxxxxxx> writes:
> On Tue, May 05, 2020 at 02:24:18PM -0400, Jeff King wrote:
>
>> But _if_ we can read from other refs in the repository, I would be very
>> happy if we parsed config out of refs/ci/branches or something. It feels
>> like that's something that ought to be possible, but I haven't quite
>> figured out a way to do it.
>
> OK, I finally figured this out. The result is the patch below, which I
> think should make everybody happy. Or at least has the ability to do so
> if they're willing to push a config ref. ;)
That sounds good.
> Subject: [PATCH] ci: allow per-branch config for GitHub Actions
>
> Depending on the workflows of individual developers, it can either be
> convenient or annoying that our GitHub Actions CI jobs are run on every
> branch. As an example of annoying: if you carry many half-finished
> work-in-progress branches and rebase them frequently against master,
> you'd get tons of failure reports that aren't interesting (not to
> mention the wasted CPU).
OK.
> This commit adds a new job which checks a special ref within the
> repository for CI config, and (optionally) causes all of the other jobs
> to be skipped.
Nice---that way, all existing jobs do not even need to know about
the special controlling ref.
> Right now the logic is to run CI for all branches by default, unless a
> whitelist exists, in which case the branch must be mentioned there
> (using its fully qualified ref name).
So there is no wildcard? Not really complaining, but am wondering.
> We could easily add in a
> blacklist, as well.
OK.
> Or since we're running a shell in a VM, we really
> could just run "./allow-ref $refname" and let individual forks specify
> whatever shell code they like.
I presume that you are saying "checking out the tree of refs/ci/config
and there is a program allow-ref that can tell which one to run ci on"?
> After writing that, I think we probably ought to just do the allow-ref
> thing from the start, and skip this whitelist logic. Then we should
> never need to change this workflow file again. People can implement
> whatever weird custom logic they want to.
Probably.
> jobs:
> + check-ci:
> + runs-on: ubuntu-latest
> + outputs:
> + enabled: ${{ steps.check-ref.outputs.enabled }}
> + steps:
> + - uses: actions/checkout@v2
> + continue-on-error: true
> + with:
> + ref: refs/ci/config
> + - id: check-ref
> + name: check whether CI is enabled for ref
> + run: |
> + enabled=yes
> + if test -e ref-whitelist &&
> + ! grep '^${{ github.ref }}$' ref-whitelist
> + then
> + enabled=no
> + fi
> + echo "::set-output name=enabled::$enabled"
> +
> windows-build:
> + needs: check-ci
> + if: needs.check-ci.outputs.enabled == 'yes'
> runs-on: windows-latest
> steps:
> - uses: actions/checkout@v1
Oh, quite nice. Simple and clean.
