GitHub - cloudposse/github-action-matrix-outputs-write: Workaround implementation

Workaround implementation - Write matrix jobs outputs

Introduction

GitHub actions have an Jobs need a way to reference all outputs of matrix jobs issue. If there is a job that runs multiple times with strategy.matrix only the latest iteration's output availiable for reference in other jobs.

There is a workaround to address the limitation. We implement the workaround with two GitHub Actions:

v1 - What's new

Important

cloudposse/github-action-matrix-outputs-write@v1+ is not currently supported on GHES yet. If you are on GHES, you must use v0.

The release of cloudposse/github-action-matrix-outputs-write@v1 and cloudposse/github-action-matrix-outputs-read@v1 are major changes to the backend architecture of Artifacts. They have numerous performance and behavioral improvements.

For more information, see the @actions/artifact documentation.

Breaking Changes

On self hosted runners, additional firewall rules may be required.
Outputs writen with cloudposse/github-action-matrix-outputs-write@v1 can not be read by cloudposse/github-action-matrix-outputs-read@v0and below versions.

Usage

Example how you can use workaround to reference matrix job outputs.

  name: Pull Request
  on:
    pull_request:
      branches: [ 'main' ]
      types: [opened, synchronize, reopened, closed, labeled, unlabeled]

  jobs:
    build:
      runs-on: ubuntu-latest
      strategy:
        matrix:
          platform: ["i386", "arm64v8"]
      steps:
        - name: Checkout
          uses: actions/checkout@v3

        - name: Build
          id: build
          uses: cloudposse/github-action-docker-build-push@1.9.0
          with:
            registry: registry.hub.docker.com
            organization: "${{ github.event.repository.owner.login }}"
            repository: "${{ github.event.repository.name }}"
            build-args: |-
              PLATFORM=${{ matrix.platform }}

        ## Write for matrix outputs workaround 
        - uses: cloudposse/github-action-matrix-outputs-write@v1
          id: out
          with:
            matrix-step-name: ${{ github.job }}
            matrix-key: ${{ matrix.platform }}
            outputs: |-
              image: ${{ steps.build.outputs.image }}:${{ steps.build.outputs.tag }}
              ## Multiline string
              tags: ${{ toJson(steps.build.outputs.image) }}

    ## Read matrix outputs 
    read:
      runs-on: ubuntu-latest
      needs: [build]
      steps:
        - uses: cloudposse/github-action-matrix-outputs-read@v1
          id: read
          with:
            matrix-step-name: build

      outputs:
        result: "${{ steps.read.outputs.result }}"
  
    ## This how you can reference matrix output
    assert:
      runs-on: ubuntu-latest
      needs: [read]
      steps:
        - uses: nick-fields/assert-action@v1
          with:
            expected: ${{ registry.hub.docker.com }}/${{ github.event.repository.owner.login }}/${{ github.event.repository.name }}:i386
            ## This how you can reference matrix output
            actual: ${{ fromJson(needs.read.outputs.result).image.i386 }}
  
        - uses: nick-fields/assert-action@v1
          with:
            expected: ${{ registry.hub.docker.com }}/${{ github.event.repository.owner.login }}/${{ github.event.repository.name }}:arm64v8
            ## This how you can reference matrix output
            actual: ${{ fromJson(needs.read.outputs.result).image.arm64v8 }}

Reusable workflow example

Reusable workflow that support matrix outputs

./.github/workflow/build-reusabled.yaml

name: Build - Reusable workflow
on:
  workflow_call:
    inputs:
      registry:
        required: true
        type: string
      organization:
        required: true
        type: string
      repository:
        required: true
        type: string
      platform:
        required: true
        type: string
      matrix-step-name:
        required: false
        type: string
      matrix-key:
        required: false
        type: string
    outputs:
      image:
        description: "Image"
        value: ${{ jobs.write.outputs.image }}

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v3

      - name: Build
        id: build
        uses: cloudposse/github-action-docker-build-push@1.9.0
        with:
          registry: ${{ inputs.registry }}
          organization: ${{ inputs.organization }}
          repository: ${{ inputs.repository }}
          build-args: |-
            PLATFORM=${{ inputs.platform }}
    outputs:
      image: ${{ needs.build.outputs.image }}:${{ needs.build.outputs.tag }}

  write:
    runs-on: ubuntu-latest
    needs: [build]
    steps:        
      ## Write for matrix outputs workaround 
      - uses: cloudposse/github-action-matrix-outputs-write@v1
        id: out
        with:
          matrix-step-name: ${{ inputs.matrix-step-name }}
          matrix-key: ${{ inputs.matrix-key }}
          outputs: |-
            image: ${{ needs.build.outputs.image }}

    outputs:
      image: ${{ fromJson(steps.out.outputs.result).image }}
      image_alternative: ${{ steps.out.outputs.image }}

Then you can use the workflow with matrix

name: Pull Request
on:
  pull_request:
    branches: [ 'main' ]
    types: [opened, synchronize, reopened, closed, labeled, unlabeled]

jobs:
  build:
    usage: ./.github/workflow/build-reusabled.yaml
    strategy:
      matrix:
        platform: ["i386", "arm64v8"]
    with:
      registry: registry.hub.docker.com
      organization: "${{ github.event.repository.owner.login }}"
      repository: "${{ github.event.repository.name }}"
      platform: ${{ matrix.platform }}
      matrix-step-name: ${{ github.job }}
      matrix-key: ${{ matrix.platform }}

  ## Read matrix outputs 
  read:
    runs-on: ubuntu-latest
    needs: [build]
    steps:
      - uses: cloudposse/github-action-matrix-outputs-read@v1
        id: read
        with:
          matrix-step-name: build

    outputs:
      result: "${{ steps.read.outputs.result }}"

  ## This how you can reference matrix output
  assert:
    runs-on: ubuntu-latest
    needs: [read]
    steps:
      - uses: nick-fields/assert-action@v1
        with:
          expected: ${{ registry.hub.docker.com }}/${{ github.event.repository.owner.login }}/${{ github.event.repository.name }}:i386
          ## This how you can reference matrix output
          actual: ${{ fromJson(needs.read.outputs.result).image.i386 }}

      - uses: nick-fields/assert-action@v1
        with:
          expected: ${{ registry.hub.docker.com }}/${{ github.event.repository.owner.login }}/${{ github.event.repository.name }}:arm64v8
          ## This how you can reference matrix output
          actual: ${{ fromJson(needs.read.outputs.result).image.arm64v8 }}

or as a simple job

name: Pull Request
on:
  pull_request:
    branches: [ 'main' ]
    types: [opened, synchronize, reopened, closed, labeled, unlabeled]

jobs:
  build:
    usage: ./.github/workflow/build-reusabled.yaml
    with:
      registry: registry.hub.docker.com
      organization: "${{ github.event.repository.owner.login }}"
      repository: "${{ github.event.repository.name }}"
      platform: "i386"

  ## This how you can reference single job output
  assert:
    runs-on: ubuntu-latest
    needs: [build]
    steps:
      - uses: nick-fields/assert-action@v1
        with:
          expected: ${{ registry.hub.docker.com }}/${{ github.event.repository.owner.login }}/${{ github.event.repository.name }}:i386
          ## This how you can reference matrix output
          actual: ${{ needs.build.outputs.image }}

Related Projects

Check out these related projects.

github-action-matrix-outputs-read - Matrix outputs read

References

For additional context, refer to some of these links.

github-actions-workflows - Reusable workflows for different types of projects
example-github-action-release-workflow - Example application with complicated release workflow

✨ Contributing

This project is under active development, and we encourage contributions from our community.

Many thanks to our outstanding contributors:

For 🐛 bug reports & feature requests, please use the issue tracker.

In general, PRs are welcome. We follow the typical "fork-and-pull" Git workflow.

Review our Code of Conduct and Contributor Guidelines.
Fork the repo on GitHub
Clone the project to your own machine
Commit changes to your own branch
Push your work back up to your fork
Submit a Pull Request so that we can review your changes

NOTE: Be sure to merge the latest changes from "upstream" before making a pull request!

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License

Preamble to the Apache License, Version 2.0

Complete license is available in the LICENSE file.

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