Github Actions cheatsheet

GitHub Actions is a CI/CD platform that enables automation of software workflows, allowing developers to build, test, and deploy code right from their GitHub repositories.

Github Action Workflows are defined in special YAML files, typically stored in a .github/workflows directory in the github repository.

name: hello-world
on: push
jobs:
  hello-world-job:
    runs-on: ubuntu-latest
    steps:
      - name: Hello World
        run: echo "Hello World!"

Viewing your workflow runs

• On GitHub.com, navigate to the main page of the repository.
• Under your repository name, click Actions.
• In the left sidebar, click the workflow you want to display, in this example "hello-world"

name: learn-github-actions
run-name: ${{ github.actor }} is learning GitHub Actions
on: [push]
jobs:
  check-bats-version:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v3
        with:
          node-version: "14"
      - run: npm install -g bats
      - run: bats -v

name: Event-trigger-on-push-example

on: [push] # event is defined here

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Run a script
        run: echo "This workflow runs on every push to the repository."

Event Triggers

Single Job:

name: Single Job
on: [push]
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Run a build script
        run: script/build

Multiple Jobs:

name: CI Workflow

on: [push]

jobs:
  job-1:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Runs job 1
        run: echo "Running Job 1"

  job-2:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Runs job 2
        run: echo "Running Job 2"

  job-3:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Runs job 3
        run: echo "Running Job 3"

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      # step 1
      - name: Check out repository
        uses: actions/checkout@v2

      # step 2
      - name: Set up Node.js
        uses: actions/setup-node@v2
        with:
          node-version: "14"

      # step 3
      - name: Install dependencies
        run: npm install

      # step 4
      - name: Run tests
        run: npm test

Github Hosted Runner:

name: Workflow
on: [push]
jobs:
  build:
    runs-on: ubuntu-latest # default runner
    steps:
      - uses: actions/checkout@v2
      - name: Run a script
        run: echo "Hello, world!"

Self Hosted Runner

name: Workflow with Self-Hosted Runner
on: [push]
jobs:
  build:
    runs-on: self-hosted
    steps:
      - uses: actions/checkout@v2
      - name: Run a script
        run: echo "Hello from self-hosted runner!"

Custom variable defined using environments.

jobs:
  build:
    runs-on: ubuntu-latest
    env:
      CUSTOM_VARIABLE: "Hello, World!" # Custom variable defined using env:
    steps:
      - name: Check environment variable
        run: echo "Value of CUSTOM_VAR is $CUSTOM_VAR"

To add a new secret in your github repository nagivate to Repository > Settings > Security > Secrets and Variables > Actions > New Repository Secret

Example Secrets workflow:

name: Workflow with Secrets

on: [push]

jobs:
  example_job:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@v2
      - name: Use a secret
        run: echo "The secret is ${{ secrets.MY_SECRET }}"

To access your artifact navigate to Repository > Actions > Workflow Run > Artifacts

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Build project
        run: make build
      - name: Upload build artifact
        uses: actions/upload-artifact@v3 # upload Artifacts prebuilt action
        with:
          name: my-artifact
          path: path/to/artifact

Dependency caches stores downloaded packages or compiled binaries of your workflows.

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - name: Cache dependencies
        uses: actions/cache@v2 # stores downloaded packages or compiled binaries
        with:
          path: |
            path/to/dependencies
            another/path
          key: ${{ runner.os }}-deps-${{ hashFiles('**/lockfile') }} # hash of the dependency lock file is generated in the OS
      - name: Install dependencies
        run: install-command

jobs:
  build:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        node-version: [12.x, 14.x, 16.x]
        # matrix strategy runs enables you to run jobs across multiple combinations of environments and OS's
        os: [ubuntu-latest, windows-latest, macOS-latest]
    steps:
      - uses: actions/checkout@v2
      - name: Use Node.js ${{ matrix.node-version }}
        uses: actions/setup-node@v1
        with:
          node-version: ${{ matrix.node-version }}
      - run: npm install
      - run: npm test
        env:
          CI: true

Branch Conditions:

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v2
      - name: Run build
        if: github.ref == 'refs/heads/main' # "Run build" step will only execute if the current branch is main.
        run: make build

Event Trigger Conditions:

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v2
      - name: Run tests
        if: github.event_name == 'pull_request' # "Run tests" step is executed only when the workflow is triggered by a pull request event
        run: npm test

Depending on your OS, if you are running ubuntu-latest, bash commands should work

steps:
  - name: Set environment variable
    run: echo "NAME=value" >> $GITHUB_ENV

The concurrency field creates a group based on the github.head_ref. If a new run starts within the same concurrency group, it cancels any in-progress runs.

jobs:
  my_job:
    runs-on: ubuntu-latest
    concurrency:
      group: ${{ github.head_ref }}
      cancel-in-progress: true
    steps:
      - name: Run a script
        run: echo "Running script..."