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github-actions-practice

• Last Updated: 2024-11-01
• Python Version: 3.12

Github Actions Table

1. pull_request

• github.sha is not the latest commit sha ref <- you can use this sha for the closed type to get the latest commit on the main branch.
• github.event.pull_request.head.sha is the sha of the lastest commit on the pr branch ref
• github.event.pull_request.head.ref: pr branch name. e.g. BRANCH: ${{ github.event_name == 'push' && github.ref_name || github.event.pull_request.head.ref }}: branch name for push and pull_request event (need to set in env)
• github.event.number: pull request number. e.g. ${{ github.event_name == 'push' && github.ref_name || format('pr-{0}', github.event.number) }} get tag name (branch name for push and pr-xxx for pr)

2. release

3. push

• BRANCH: ${{ github.event_name == 'push' && github.ref_name || github.event.pull_request.head.ref }}: branch name for push and pull_request event (need to set in env)

4. schedule

5. workflow_dispatch

6. workflow_call

6. Matrix

1. env cannot be used for matrix.
2. The matrix value cannot be used in if for its job.
3. fromJson is often used to generate matrix (ref: https://docs.github.com/en/actions/learn-github-actions/expressions)

CheatSheet

• conditional needs: you can run main-job when dependent-job completed successfully or is skipped

  jobs:
    dependent-job:
      ...
    main-job:
      needs: dependent-job
      if: needs.dependent-job.result == 'success' || needs.dependent-job.result == 'skipped'`
  

• Available commands by default (default-commands.yml)

  • zip, aws, jq, yq

  • gh

    <details><summary>example</summary>

    - uses: actions/checkout@v3 # to get the context
    
    - name: gh
      env:
        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        PR_NUMBER: ${{ github.event.pull_request.number }}
      run: gh pr comment $PR_NUMBER --body "Hi from GitHub CLI"
    

    • default-commands.yml
    • create-pr-if-outdated.yml
    </details>

• Events to Trigger workflow

  • pull_request
    • default types: opened, synchronize, or reopened.
    • specify types:

      on:
        pull_request:
          types: [assigned, opened, synchronize, reopened, ready_for_review]
      

      • action: ${{ github.event.action }}: You can get edited, synchronize, ready_for_review, (opened ❌)
    • Get PR number: PR_NUMBER=${{ github.event.number }}
    • Get sha: ${{ github.sha }}
    • Get repository: ${{ github.repository }}
    • Get label name for labeled type: ${{ github.event.label.name }}
    • Get source branch: ${{ github.head_ref }}
    • Get base branch: ${{ github.base_ref }}
    • Whether the PR is draft: github.event.pull_request.draft
    • Whether the label is in the whitelist: if: ${{ github.event.action == 'labeled' && contains(toJson('["test", "build"]'), github.event.label.name) }}
    • If merged pr has label release: if: ${{ github.event.pull_request.merged == true && contains( github.event.pull_request.labels.*.name, 'release') }}
    • Whether pull_request has 'test' label: if: ${{ contains( github.event.pull_request.labels.*.name, 'test') }}
  • release
    • Whether release is from main branch: if: github.event.release.target_commitish == 'main'
  • push ...

• Context

  • Whether commit message contains [skip ci]: (maybe you can also consider using GitHub Actions: Skip pull request and push workflows with [skip ci])

    <details>

    if: contains(github.event.head_commit.message, '[skip ci]') == false
    

    </details>

  • Skip draft PR: if: github.event.pull_request.draft == false

• Outputs

  • Set output: echo "<your var name>=<value>" >> "$GITHUB_OUTPUT"

  • Use output: ${{ steps.<step_id>.outputs.<your var name> }}

  • Skip next job based on the result of a dependent job

    <details>

      skipci:
        runs-on: ubuntu-18.04
        outputs:
          is_skip: ${{ steps.is_skip.outputs.is_skip }}
        steps:
          - name: Set is_skip
            id: is_skip
            run: echo "is_skip=${{ contains(github.event.head_commit.message, '[skip ci]') }}" >> "$GITHUB_OUTPUT"
          - run: echo "[skip ci] ${{ steps.is_skip.outputs.is_skip }}"
    
      test:
        runs-on: ubuntu-18.04
        needs: skipci
        if: ${{ ! needs.skipci.outputs.is_skip }}
        steps:
    

    </details>

• Environment variable

  • default environment variables

  • source branch and base brach of PR

    <details>

    env:
      SOURCE_BRANCH: ${{ github.head_ref }}
      BASE_BRANCH: ${{ github.base_ref }}
    

    </details>

• Environment

  environment:
    name: ${{ github.event_name == 'release' && 'production' || github.event_name == 'push' && 'development' || github.event_name == 'pull_request' && 'pull_request' }}
  

  Example: .github/workflows/environment.yaml

• Caching

  • General: actions/cache

    • Example: https://github.com/actions/cache/blob/master/examples.md

  • Ruby: ruby/setup-ruby

  • npm: actions/setup-node

  • Go: actions/setup-go enabled by default since v4

    • github actionsのsetup-goのキャッシュは無効にした方がいいかもしれない
    • cache key is setup-go-${platform}-go-${versionSpec}-${fileHash} https://github.com/actions/setup-go@v4.0.0/src/cache-restore.ts#L32
    • hash-dependency-path go.mod by default (https://github.com/actions/setup-go#caching-dependency-files-and-build-outputs)

  • Gradle and Maven: actions/setup-java

  • Python - pip

    <details>
    • Case1: No cache:
      • pip install: 14s
    • Case2: With cache:
      • action/cache: 3s
      • pip install: 0s (skipped)
      • action/cache: 0s (skipped)
    </details>

  • Docker Layer Cache

    <details>

    Example Docker image:

    • Case1: No cache:
      • Build Docker image: 3m 13s
    • Case2: with cache but couldn't use layer cache:
      • Run satackey/action-docker-layer-caching@v0.0.8: 2m 30s
      • Build Docker image: 3m10s
      • Run satackey/action-docker-layer-caching@v0.0.8: 3m 58s
    • Case3: with cache and all the layers could use cache:
      • Run satackey/action-docker-layer-caching@v0.0.8: 3m 48s
      • Build Docker image: 1s
      • Run satackey/action-docker-layer-caching@v0.0.8: 3m 40s
    </details>

    In some case, no cache might be rather faster due to the time to spend storing and restoring a cache.

• Failure

  <details>

  name: status
  
  on: pull_request
  
  jobs:
    just-fail:
      if: github.event.pull_request.draft == true
      runs-on: ubuntu-latest
      steps:
        - id: fail_step
          run: exit 1
  
        - run: echo ${{ steps.fail_step.outcome }} # not called
  
    fail-with-post-process:
      if: github.event.pull_request.draft == true
      runs-on: ubuntu-latest
      steps:
        - id: fail_step
          continue-on-error: true
          run: exit 1
  
        - name: post process regardless of sucess or failure
          run: echo ${{ steps.fail_step.outcome }} # failure
  
        - name: make it fail when the first step failed
          if: steps.fail_step.outcome == 'failure'
          run: exit 1
  
    succeed-with-post-process:
      if: github.event.pull_request.draft == true
      runs-on: ubuntu-latest
      steps:
        - id: succeed_step
          continue-on-error: true
          run: echo succeed
  
        - name: post process regardless of sucess or failure
          run: echo ${{ steps.fail_step.outcome }} # success
  
        - name: make it fail when the first step failed
          if: steps.fail_step.outcome == 'failure'
          run: exit 1
  
    fail-with-post-process-for-failure:
      if: github.event.pull_request.draft == true
      runs-on: ubuntu-latest
      steps:
        - id: fail_step
          run: exit 1
  
        - if: failure()
          name: post process only called when the first step fails
          run: echo ${{ steps.fail_step.outcome }} # failure
  
    succeed-with-post-process-for-failure:
      if: github.event.pull_request.draft == true
      runs-on: ubuntu-latest
      steps:
        - id: succeed_step
          run: echo succeed
  
        - if: failure()
          name: post process only called when the first step fails
          run: echo ${{ steps.fail_step.outcome }}
  
    succeed:
      runs-on: ubuntu-latest
      steps:
        - id: suceed_step
          continue-on-error: true
          run: echo succeed
  
        - run: echo ${{ steps.suceed_step.outcome }} # success
  
        - if: steps.fail_step.outcome == 'failure'
          run: exit 1
  

  </details>

• Example

  • Test mvn with MySQL

    <details>

      test:
        runs-on: ubuntu-latest
    
        services:
          mysql:
            image: mysql:5.7
            options: --health-cmd "mysqladmin ping -h localhost" --health-interval 20s --health-timeout 10s --health-retries 10
            ports:
              - 3306
            env:
              MYSQL_ROOT_PASSWORD: root_password
              MYSQL_DATABASE: test_db
    
        steps:
          - uses: actions/checkout@v1
          - uses: actions/cache@v1
            with:
              path: ~/.m2/repository
              key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
              restore-keys: |
                ${{ runner.os }}-maven-
          - name: Set up JDK 1.8
            uses: actions/setup-java@v1
            with:
              java-version: 1.8
          - name: Test with Maven
            env:
              MYSQL_PORT: ${{ job.services.mysql.ports[3306] }}
              MYSQL_HOST: 127.0.0.1
              MYSQL_USERNAME: root
              MYSQL_PASSWORD: root_password
              MYSQL_DB: test_db
            run: mvn test
    

    </details>