GitHub Action
alls-green
A check for whether the dependency jobs are all green.
Do you have more than one job in your GitHub Actions CI/CD workflows setup? Do you use branch protection? Are you annoyed that you have to manually update the required checks in the repository settings hoping that you don't forget something on each improvement of the test matrix structure?
Yeah.. me too! But there's a solution — you can make a single check
job listing all of the other jobs in its needs
list. How about that?
🤯 Now you can add only that single job to your branch protection
settings and you won't have to maintain that list manually anymore.
Right..? Wrong 🙁 — apparently, in case when something fails, the
check
job's result is set to skipped
and not failed
as one would
expect. This is problematic and requires extra work to get it right.
Some of it is iteration over the needed jobs and checking that all their
results are set to success but it's no fun to maintain this sort of
thing in many different repositories. Also, it is mandatory to make the
check
job run always, not only when all of the needed jobs succeed.
This is why I decided to make this action to simplify the maintenance.
:wq
To use the action add a check
job to your workflow file (e.g.
.github/workflows/ci-cd.yml
) following the example below:
---
on:
pull_request:
push:
jobs:
build:
...
docs:
...
linters:
...
package-linters:
needs:
- build
...
tests:
needs:
- build
...
check:
if: always()
needs:
- docs
- linters
- package-linters
- tests
runs-on: Ubuntu-latest
steps:
- name: Decide whether the needed jobs succeeded or failed
uses: re-actors/alls-green@release/v1
with:
allowed-failures: docs, linters
allowed-skips: non-voting-flaky-job
jobs: ${{ toJSON(needs) }}
...
There are three options — allowed-failures
, allowed-skips
and
jobs
. The first two are optional but jobs
is mandatory.
allowed-failures
tells the action which jobs should not affect the
outcome if they don't succeed, by default all the jobs will
be "voting". Same goes for allowed-skips
— it won't allow the listed
jobs to affect the outcome if they are skipped but are still "voting" in
case they run. jobs
is an object representing the jobs that should
affect the decision of whether the pipeline failed or not, it is
important to pass a JSON-serialized needs
context to this argument.
Important: For this to work properly, it is a must to have the job
always run, otherwise GitHub will make it skipped
when any of the
dependencies fail. In some contexts, skipped
is interpreted as
success
which may lead to undersired, unobvious and even dangerous (as
in security breach "dangerous") side-effects.
Whether this check decided that the job matrix failed.
Failure or success result of the job matrix.
Whether this check decided that the job matrix succeeded.
An attentive reader may have noticed that there is no clear way to allow failures for specific job generated by matrixes in a simple manner, through action inputs. This is due to the fact that those individual matrix job statuses are not exposed by the GitHub platform.
Although, there is a solution — use a continue-on-error
job-level setting with a dynamic matrix-dependent value. In this case,
the matching jobs will not influence the resulting outcome of the
whole matrix and this action will "see" that as a success (provided
that the jobs that are not allowed to fail succeed, of course).
Here's a simplified example of what testing against an unstable Python 3.11 release that is allowed to fail might look like:
---
... # Some sections have been removed from the example to simplify it
jobs:
tests:
runs-on: ubuntu-latest
matrix:
python-version:
- >-
3.10
- ~3.11.0-0
continue-on-error: >-
${{ contains(matrix.python-version, '~') && true || false }}
steps:
- ...
check:
if: always()
needs:
- tests
runs-on: ubuntu-latest
steps:
- name: Decide whether the needed jobs succeeded or failed
uses: re-actors/alls-green@release/v1
with:
jobs: ${{ toJSON(needs) }}
...
We've seen it being integrated into some projects of @aio-libs (notably, aiohttp), Ansible Collections Community, attrs, @CherryPy, conda, coveragepy, Open edX, pip-tools, setuptools, structlog, spaceship-prompt, Towncrier, @PyCA, @PyPA and @pytest ecosystems. And here's more: https://github.com/re-actors/alls-green/network/dependents.
My inspiration came from Zuul — a project gating system that
practices having one "check-gate" that depends on multiple individual
checks. Later when I started implementing this practice across the
projects that I maintain, I discovered that I was not the only one who
got the same idea @graingert posted a similar solution on the GitHub
Community Forum. At some point I noticed that GitHub's
auto-merge merges Dependabot PRs that are broken despite having branch
protection enabled in the aiohttp repository, it wasn't obvious why.
I stumbled on the solution accidentally, it was implemented in the
PyCA/cryptography repository — the credit for that goes to
@reaperhulk. He listed all of the needed jobs manually in the check
.
With those findings I've spent some time on experimentation and
composing a more generic solution — this is how this GitHub Action came
to be.
The contents of this project is released under the BSD 3-clause license.