https://github.com/valentinh/gh-actions-nested-matrices
https://github.com/valentinh/gh-actions-nested-matrices
Last synced: 15 days ago
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- Host: GitHub
- URL: https://github.com/valentinh/gh-actions-nested-matrices
- Owner: ValentinH
- Created: 2022-11-11T20:56:25.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2022-11-12T21:37:57.000Z (over 3 years ago)
- Last Synced: 2025-03-25T10:22:06.845Z (over 1 year ago)
- Language: JavaScript
- Size: 54.7 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# GH Actions with nested matrices
This repository contains an example monorepo (created with [the official Turborepo example](https://turbo.build/repo/docs/getting-started/create-new)).
The monorepo isn't the point here: the goal is to present a technique to build Github Actions made of dynamically nested matrices.
Indeed, GH Actions allows creating matrices like documented [here](https://docs.github.com/en/actions/using-jobs/using-a-matrix-for-your-jobs).
The examples only shows how to create static matrices but there are multiple blog posts explaining how to dynamically generate matrices using the `fromJSON()` function such as [this one](https://michaelheap.com/dynamic-matrix-generation-github-actions/).
However, I needed to go even further: have nested matrices with the second one being dynamic!
Here's my use case:
1. create a matrix of each app/package to test
2. for each target, create a dynamic matrix to split the tests in multiple jobs
For a while, I thought that this was not possible because the current actions syntax doesn't allow specifying such a setup.
However, today I discovered a feature called [reusable workflows](https://docs.github.com/en/actions/using-workflows/reusing-workflow) (never too late) which enables us to achieve what I described above! 🎉
Indeed, you can call a reusable workflow from within a matrix like this:
```yaml
test:
strategy:
fail-fast: false
matrix:
scope: ['web', 'docs', 'ui']
uses: ./.github/workflows/test.yml
with:
target: ${{ matrix.scope }}
```
And then, you can create a dynamic matrix inside the reusable workflow! 😎
The actions graph doesn't nicely renders the nested matrices (yet) but it works fine:
