Metadata syntax for GitHub Actions

name: 'Hello Custom Action'
description: 'Greet someone and record the time'
author: 'Siddharth'
branding:
  icon: 'award'
  color: 'green'
inputs:
  who-to-greet:
    description: 'The person to greet'
    required: true
    default: 'Alice'
    deprecationMessage: 'This input will be removed in the next major version.'
outputs:
  time:
    description: 'Timestamp when greeting occurred'
runs:
  using: 'node20'

name: 'Hello JS Action'
description: 'Greets a user'
inputs:
  who-to-greet:
    description: 'Person to greet'
    required: true
outputs:
  time:
    description: 'Greeting timestamp'
runs:
  using: 'node20'           # node16 | node18 | node20, etc.
  pre: 'setup.js'           # Optional: runs before main
  pre-if: "runner.os == 'linux'"
  main: 'index.js'          # Entrypoint script
  post: 'cleanup.js'        # Optional: runs after main
  post-if: "runner.os == 'linux'"

name: 'Hello Docker Action'
description: 'Greets a user in a container'
inputs:
  who-to-greet:
    description: 'Person to greet'
    required: true
outputs:
  time:
    description: 'Greeting timestamp'
runs:
  using: 'docker'
  image: 'Dockerfile'         # Or registry reference: docker://alpine:3.8
  args:
    - ${{ inputs.who-to-greet }}
  pre-entrypoint: 'setup.sh'    # Optional script before container ENTRYPOINT
  entrypoint: 'main.sh'         # Overrides Dockerfile ENTRYPOINT
  post-entrypoint: 'cleanup.sh' # Optional script after entrypoint

name: 'Hello Composite Action'
description: 'Greets a user with multiple steps'
inputs:
  who-to-greet:
    description: 'Person to greet'
    required: true
outputs:
  time:
    description: 'Greeting timestamp'
runs:
  using: 'composite'
  steps:
    - run: ./scripts/setup.sh
      shell: bash           # bash | sh | pwsh | python
    - run: echo "Hello, ${{ inputs.who-to-greet }}"
    - uses: docker://alpine:3.8
      with:
        entrypoint: /bin/sh