[gh/wf/linux.yml] allow workflow cancellation

[xmkg]

Allow in-progress workflows to be canceled when an external event requests them (e.g., the workflow run has been superseded with a new commit).

MULTI-1939

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.53%. Comparing base (896fcb7) to head (614b3bd).
Report is 3421 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4030   +/-   ##
=======================================
  Coverage   89.53%   89.53%           
=======================================
  Files         260      260           
  Lines       14741    14741           
=======================================
  Hits        13198    13198           
  Misses       1543     1543           

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[ricab]

Good, this addresses #4048 now too.

[xmkg]

Good, this addresses #4048 now too.

Github's workflow cancellation is a real headache. The matrix part of the job seems resistant to every kind of cancellation request I've tried, except for force cancel. I'm still investigating why that is. I'll add some trace steps to jobs to see whether the cancellation signals (SIGINT, SIGTERM, etc.) are reaching to the steps at all.

[xmkg]

Good, this addresses #4048 now too.

Github's workflow cancellation is a real headache. The matrix part of the job seems resistant to every kind of cancellation request I've tried, except for force cancel. I'm still investigating why that is. I'll add some trace steps to jobs to see whether the cancellation signals (SIGINT, SIGTERM, etc.) are reaching to the steps at all.

In case anyone needs I'm using the following bash functions to kill workflows forcefully:

github-kill-workflow(){
gh api \
  --method POST \
  -H "Accept: application/vnd.github+json" \
  -H "X-GitHub-Api-Version: 2022-11-28" \
  /repos/$1/actions/runs/$2/force-cancel
}


github-kill-workflow-by-url() {
url="$1"

repo=$(echo "$url" | awk -F'[/?]' '{print $4 "/" $5}')
run_id=$(echo "$url" | awk -F'[/?]' '{print $8}')

echo "repo: $repo"
echo "run_id: $run_id"

github-kill-workflow $repo $run_id

}

Include them in your .bashrc, then use it like

github-kill-workflow-by-url https://github.com/canonical/multipass/actions/runs/14502559305?pr=4030

[xmkg]

The matrix part of the job seems resistant to every kind of cancellation request I've tried, except for force cancel

Finally figured out why that is.

    if: |
      ${{
        success()
        || needs.Lint.result == 'skipped'
        || ( needs.Lint.result == 'failure'
             && github.event_name == 'pull_request' )
      }}

The BuildAndTest is cancellable after commenting out the precondition.

To cancel the workflow run, the server re-evaluates if conditions for all currently running jobs. If the condition evaluates to true, the job will not get canceled.

So, this expression somehow evaluates to true on re-check, even with !cancelled() && (...) addition. That's enough head-banging for today: I'll wrap this up tomorrow.

[xmkg]

@ricab finally, everything works as it should. A new push cancels the previous runs, and the "cancel workflow" button works.

[ricab]

Good job Mustafa, thanks! 2 tiny things inline, but pre-approving.

[ricab]

That's a lot of line splitting now, but ok...

[ricab]

Alright, LGTM, thanks again @xmkg!

[ricab]

I would just like to get @sharder996's review on this one if possible.

[sharder996]

Yup, I think it looks good. Biggest thing is that Github will group CI runs by head-ref now.