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October 24, 2024

Github Action: workflow_dispatch

github-actions

Contents

Workflow Dispatch Menu

String, Dropdown List and Boolean
---
on:
  workflow_dispatch:
    inputs:
      tag:
        type: string
        description: "Release tag (e.g., v1.0.0)"
        required: true
        default: v1.0.0
      boolean:
        type: boolean
        description: True or False
      servicename:
        type: choice
        description: Make a choice
        options:
          - foo
          - bar
          - baz

Work with inputs from workflow_dispatch

Retrieve the value

We get the value in shell script via

run: echo ${{ github.event.inputs.tag }}
Determine whether a step should be run (Like a Mapping)

The following can be treated as a "mapping" to determine which parameter to use if we have made a reusable github action. A typical example is a javascript action because all of them must be reusable by nature, see Fundamentals of Github Actions and scroll to Javascript Actions section.

  • For unknown reason the expression ${{ github.event.inputs.servicename == 'foo' }} does not work because the available expression syntax is limited to specific functions and operators

  • Instead we use:

    • if: contains(github.event.inputs.servicename, 'foo')
      or
    • if: github.event.inputs.servicename == 'foo'

  • More examples from official documentation

jobs:
  test:
   runs-on: ubuntu-latest
   steps:
    - name: "Checkout source code"
      uses: actions/checkout@v3
      with:
          fetch-depth: 0

  foo-service:
    runs-on: ubuntu-latest
    if: always() && github.event.inputs.servicename == 'foo'
    steps:
    - name: "Checkout source code"
      uses: actions/checkout@v3

  bar-service:
    runs-on: ubuntu-latest
    if: always() && github.event.inputs.servicename == 'bar'
    steps:
    - name: "Checkout source code"
      uses: actions/checkout@v3

Note that we add always() because the previous step may partially succeed for unknown reason but we still want to continue.

Note that the subsequent jobs will not continue unless you have

  • if: success() or
  • if: failure()

etc expression.

Validate tha inputs from workflow_dispatch

For example, we can enforce the tag to follow some specific pattern:

jobs:
  validate:
    runs-on: ubuntu-latest
    steps:
      - name: Check trigger type
        id: check-trigger
        run: |
          if ! [[ ${{ github.event.inputs.tag }} =~ ^v[0-9]+\.[0-9]+\.[0-9]+$ ]]; then
            echo "Tag must follow format v*.*.* (e.g., v1.0.0)"
            exit 1
          fi
  deployment:
    runs-on: ubuntu-latest
    environment: deployment
    ...
Add Tag to a branch Using Value from workflow_dispatch

Suppose that we have input a tag and want to tag a branch once a deployment succeeded, we add a final step to a job:

      # ... other step
      - name: Create tag
        run: |
          # Print current branch for verification
          echo "Current branch: $(git branch --show-current)"

          # Create tag on current branch
          git tag ${{ github.event.inputs.tag }} ${{ github.ref_name }}
          git push origin ${{ github.event.inputs.tag }}

          echo "Created tag ${{ github.event.inputs.tag }} on branch ${{ github.ref_name }}"