CI Matrix Planner

A reusable GitHub Action to plan your CI job matrix based on action inputs, workflow dispatch inputs, pull request metadata, labels, or commit messages.
It helps you control which jobs and targets are executed in your workflows, making CI faster, more configurable, and easier to maintain across projects.

✨ Features

• Parse directives from:
  • explicit action inputs
  • workflow_dispatch event inputs
  • PR labels
  • PR title/body
  • PR head commit or push head commit
• Supported directives:
  • mode=components (default): run split jobs (feelpp, testsuite, toolboxes, mor, python).
  • mode=full: collapse into full-build job(s) (e.g. feelpp-full).
  • only=... → run only specific jobs (auto-detects full mode if full job is specified).
  • skip=... → skip specific jobs.
  • targets=... → override matrix targets.
  • include=... / exclude=... → adjust targets incrementally.
  • pkg=... → select packaging targets (profile-driven).
  • pkg-include=... / pkg-exclude=... → adjust packaging targets incrementally.
• profile: packaging turns the planner into a packaging-first planner and emits the packaging matrix as the primary matrix_json.
• Auto-detect full mode: Using only=feelpp-full automatically switches to full mode.
• Mode-specific targets: Full mode can have its own default targets.
• Multiple full jobs: Support for multiple jobs in full mode.
• Project-specific config via .github/plan-ci.json.
• Outputs are ready to use in if: conditions and matrix: fromJSON(...).
• Built-in defaults if no config is provided.
• Includes unit tests and its own CI workflow.

🔧 Inputs

Input	Description	Default
config-path	Path to the JSON config file in the consumer repo (see below).	.github/plan-ci.json
mode-input	Override mode directly.	""
message-override	Override the directive message directly.	""
labels-override	Comma-separated labels to use instead of payload labels.	""
github-token	Token used to read PR/push commit messages via the GitHub API.	""
profile	Explicit profile to resolve when using profile-based configs.	""

📤 Outputs

Output	Description
mode	components, full, or packaging
only_jobs	Space-separated list of jobs forced by only=...
only_jobs_json	JSON array of jobs forced by only=...
skip_jobs	Space-separated list of jobs to skip (skip=... or inferred from message tokens)
skip_jobs_json	JSON array of jobs to skip
targets_json	JSON array of selected target keys
targets_list	Space-separated list of selected target keys
matrix_json	JSON workflow matrix object for the selected profile
enabled_jobs	Space-separated list of jobs that will run
enabled_jobs_json	JSON array of jobs that will run
warnings_json	JSON array of planner warnings
profile	Resolved profile (for profile-based configs)
enabled_profiles_json	JSON array of enabled profiles
pkg_enabled	Whether packaging targets are enabled
pkg_targets_json	JSON array of packaging targets
pkg_matrix_json	JSON packaging matrix object
pkg_matrix_rows_json	JSON array of packaging matrix rows
directive_source	Source used for directive harvesting
head_commit_sha	Commit SHA used when directives were harvested from a commit

📄 Example Config (.github/plan-ci.json)

Simple config (backwards compatible)

{
  "jobs": ["feelpp", "testsuite", "toolboxes", "mor", "python"],
  "targets": ["ubuntu:24.04", "debian:13", "fedora:42"],
  "defaults": {
    "mode": "components",
    "jobs": ["feelpp", "testsuite", "toolboxes", "mor", "python"],
    "targets": ["ubuntu:24.04"]
  },
  "fullBuild": { "job": "feelpp-full" }
}

Advanced config with mode-specific settings

{
  "jobs": ["feelpp", "testsuite", "toolboxes", "mor", "python"],
  "targets": ["ubuntu:24.04", "debian:13", "fedora:42"],
  "defaults": {
    "mode": "components",
    "targets": ["ubuntu:24.04"]
  },
  "modes": {
    "components": {
      "jobs": ["feelpp", "testsuite", "toolboxes", "mor", "python"],
      "targets": ["ubuntu:24.04"]
    },
    "full": {
      "jobs": ["feelpp-full"],
      "targets": ["ubuntu:24.04"]
    }
  }
}

Config with multiple full mode jobs

{
  "jobs": ["feelpp", "toolboxes", "mor", "python"],
  "fullBuild": {
    "jobs": ["feelpp-full", "feelpp-full-debug"],
    "targets": ["ubuntu:24.04"]
  }
}

🚀 Usage in Workflow

jobs:
  plan_ci:
    runs-on: ubuntu-latest
    outputs:
      mode:         ${{ steps.plan.outputs.mode }}
      enabled_jobs_json: ${{ steps.plan.outputs.enabled_jobs_json }}
      only_jobs:    ${{ steps.plan.outputs.only_jobs }}
      only_jobs_json: ${{ steps.plan.outputs.only_jobs_json }}
      skip_jobs_json: ${{ steps.plan.outputs.skip_jobs_json }}
      matrix_json: ${{ steps.plan.outputs.matrix_json }}
    steps:
      - uses: actions/checkout@v4
      - id: plan
        uses: feelpp/ci-matrix-planner@v1
        with:
          config-path: .github/plan-ci.json

  feelpp:
    needs: plan_ci
    if: contains(fromJSON(needs.plan_ci.outputs.enabled_jobs_json), 'feelpp')
    runs-on: self-docker
    strategy:
      matrix: ${{ fromJSON(needs.plan_ci.outputs.matrix_json) }}
    steps:
      - run: echo "Building feelpp on ${{ matrix.target }} in mode=${{ needs.plan_ci.outputs.mode }}"

Packaging Profile Usage

jobs:
  plan_pkg:
    runs-on: ubuntu-latest
    outputs:
      matrix_json: ${{ steps.plan.outputs.matrix_json }}
    steps:
      - uses: actions/checkout@v4
      - id: plan
        uses: feelpp/ci-matrix-planner@v1
        with:
          config-path: .github/plan-ci.json
          profile: packaging

  build_pkg:
    needs: plan_pkg
    strategy:
      matrix: ${{ fromJSON(needs.plan_pkg.outputs.matrix_json) }}
    steps:
      - run: echo "Packaging ${{ matrix.flavor }}:${{ matrix.dist }}"

📐 Resolution Order

The planner resolves directives in this order:

1. explicit action inputs
2. workflow_dispatch event inputs
3. PR labels
4. PR title/body
5. PR head commit message
6. push head commit message
7. git log -1

📌 Example Directives in Commit or PR

Directive	Effect
only=feelpp	Run only the feelpp job
only=feelpp-full	Auto-switch to full mode and run feelpp-full
skip=python	Skip the python job
targets=fedora:42	Restrict matrix to Fedora 42
include=debian:13	Add Debian 13 to current targets
exclude=ubuntu:22.04	Remove Ubuntu 22.04 from current targets
mode=full	Switch to full mode, run configured full job(s)
mode=full only=feelpp-full	Full mode with specific job filter
pkg=noble,trixie	Select packaging targets
pkg=none	Disable packaging targets explicitly
pkg=spack pkg-exclude=spack-openmpi	Select spack targets and exclude one

Labels

You can also use PR labels to control mode:

• ci-mode-full → Switch to full mode
• ci-mode-components → Switch to components mode (default)

🧪 Development & Testing

• The planner logic is implemented in index.js and exposed as a pure function computePlan().
• Unit tests live in tests/ with fixtures in JSON form.
• Run tests locally with:

npm install
npm test

• CI is set up in this repo to run tests automatically on push/PR.

✅ Summary

ci-matrix-planner makes your CI config-driven.
By parsing directives in commit messages, PRs, or labels, it lets you control what to build and where — without duplicating workflow YAML.