matrix-builds.md

Build app on multiple environments

Github actions provides a method to run your tests with various input. This can be useful if you want to make sure that the code builds on different versions of, e.g., Java or Node. To avoid repeating the same thing in YAML, you can use strategy

The app in this repository is Java-based and it is running on Java 11. The example how we can use it for different versions of Node:

jobs:
  build:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        node: [8, 10, 12]
    steps:
      - uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node }}

With this, the job will run three separate jobs for different versions of NodeJS; 8, 10 and 12. There can be similar solution for container based pipelines:

name: matrix-example
on: [workflow_dispatch]

jobs:
  job:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        container: ["ubuntu:bionic", "fedora:31", "opensuse/leap:42.3", "centos:8"]
    container:
      image: ${{ matrix.container }}      
    steps:
      - name: check os
        run: cat /etc/os-release

In this example pipeline runs-on ubuntu-latest for 4 different containers: "ubuntu:bionic", "fedora:31", "opensuse/leap:42.3", "centos8". This way we can skip repeating the workflows.

Tasks

we would like to build our application on different versions of Java.

Add a new job that builds on various versions

• You can add a new file on .github/workflows/matrix.yml, which will only include Clone-downand Build job.

Build job

name: Matrix workflow
on: push
jobs:
  Build:
    runs-on: ubuntu-latest
    container: gradle:6-jdk11
    steps:
      - name: Clone down repository
        uses: actions/checkout@v4       
      - name: Build application
        run: ci/build-app.sh
      - name: Test
        run: ci/unit-test-app.sh

---

• Edit build job to run for different versions of Java. Add matrix for types of containers as: ["gradle:6-jdk8", "gradle:6-jdk11", "gradle:6-jdk17"] to your build job.

strategy:
  matrix:
    container: ["gradle:6-jdk8", "gradle:6-jdk11", "gradle:6-jdk17"]

---

• Remember to edit container name:

    container:
      image: ${{ matrix.container }}     

Solution

name: Matrix workflow
on: push
jobs:
  Build:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        container: ["gradle:6-jdk8", "gradle:6-jdk11", "gradle:6-jdk17"]
    container:
      image: ${{ matrix.container }}   

    steps:
      - name: Clone down repository
        uses: actions/checkout@v4       
      - name: Build application
        run: ci/build-app.sh
      - name: Test
        run: ci/unit-test-app.sh

Results

You should have 3 jobs under Build job for different version of Java.

Questions

• Are there versions of Java which do not work?