Events and triggers

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Table of contents

1. Types of events
2. Git events
3. GitHub events
4. Scheduled events
5. Manual triggering
6. Practical exercises

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1 - Types of events

Categories

Overview

Category	Events	Usage
Git	push, pull_request	Standard CI/CD
GitHub	issues, release, fork	Automation
Schedule	cron	Recurring tasks
Manual	workflow_dispatch	Tests, deployments
External	repository_dispatch	External integrations

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2 - Git events

push

on:
  push:
    # Branches spécifiques
    branches:
      - main
      - develop
      - 'release/**'      # Pattern glob
      - '!release/beta'   # Exclusion
    
    # Tags
    tags:
      - 'v*'              # v1.0.0, v2.0.0
      - '!v*-beta'        # Exclure beta
    
    # Chemins (fichiers modifiés)
    paths:
      - 'src/**'
      - 'package.json'
      - '!**/*.md'        # Exclure markdown
    
    paths-ignore:
      - 'docs/**'
      - '*.md'

pull_request

on:
  pull_request:
    branches:
      - main
      - develop
    
    types:
      - opened            # PR ouverte
      - synchronize       # Nouveaux commits
      - reopened          # PR réouverte
      - closed            # PR fermée
      - ready_for_review  # PR prête pour review
    
    paths:
      - 'src/**'

pull_request_target

# Pour les forks (attention : risque de sécurité)
on:
  pull_request_target:
    types: [opened, synchronize]

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      # Checkout du repo cible (pas du fork)
      - uses: actions/checkout@v4

Security

pull_request_target has access to the repo's secrets. Never run unverified code from the fork!

Difference between PR events

Event	Context	Secrets	Usage
pull_request	Fork	❌ No	Standard CI
pull_request_target	Base	✅ Yes	Labeling, comments

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3 - GitHub events

issues

on:
  issues:
    types:
      - opened
      - edited
      - deleted
      - labeled
      - unlabeled
      - assigned
      - closed

jobs:
  auto-label:
    if: github.event.action == 'opened'
    runs-on: ubuntu-latest
    steps:
      - run: echo "New issue: ${{ github.event.issue.title }}"

release

on:
  release:
    types:
      - published      # Release publiée
      - created        # Release créée
      - edited         # Release modifiée
      - prereleased    # Pre-release

jobs:
  publish:
    if: github.event.action == 'published'
    runs-on: ubuntu-latest
    steps:
      - run: echo "Publishing ${{ github.event.release.tag_name }}"

workflow_run

# Déclenché après un autre workflow
on:
  workflow_run:
    workflows: ["CI"]   # Nom du workflow source
    types:
      - completed       # Terminé (succès ou échec)
    branches: [main]

jobs:
  deploy:
    # Seulement si CI réussi
    if: github.event.workflow_run.conclusion == 'success'
    runs-on: ubuntu-latest
    steps:
      - run: echo "Deploying after successful CI"

Other useful events

# Fork du repo
on: fork

# Star ajoutée
on:
  watch:
    types: [started]

# Discussion créée
on:
  discussion:
    types: [created]

# Package publié
on:
  package:
    types: [published]

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4 - Scheduled events

cron syntax

on:
  schedule:
    # ┌───────────── minute (0 - 59)
    # │ ┌───────────── hour (0 - 23)
    # │ │ ┌───────────── day of month (1 - 31)
    # │ │ │ ┌───────────── month (1 - 12)
    # │ │ │ │ ┌───────────── day of week (0 - 6)
    # │ │ │ │ │
    # * * * * *
    - cron: '0 0 * * *'     # Tous les jours à minuit
    - cron: '30 8 * * 1-5'  # Lun-Ven à 8h30
    - cron: '0 */6 * * *'   # Toutes les 6 heures

Common examples

Expression	Description
0 0 * * *	Every day at midnight UTC
0 8 * * 1	Every Monday at 8am
0 0 1 * *	First day of the month
*/15 * * * *	Every 15 minutes
0 0 * * 0	Every Sunday

Complete example

name: Nightly Build

on:
  schedule:
    - cron: '0 2 * * *'  # 2h du matin UTC

jobs:
  nightly:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      
      - name: Run nightly tests
        run: npm run test:e2e
      
      - name: Send report
        run: ./send-report.sh

Note

• Schedules use the UTC time zone
• Possible delay of up to 15 minutes during peak load
• Only triggers on the default branch

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5 - Manual triggering

workflow_dispatch

on:
  workflow_dispatch:
    inputs:
      environment:
        description: 'Environment to deploy'
        required: true
        type: choice
        options:
          - staging
          - production
        default: 'staging'
      
      version:
        description: 'Version to deploy'
        required: true
        type: string
      
      dry_run:
        description: 'Dry run mode'
        required: false
        type: boolean
        default: false

jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      - name: Deploy
        run: |
          echo "Environment: ${{ inputs.environment }}"
          echo "Version: ${{ inputs.version }}"
          echo "Dry run: ${{ inputs.dry_run }}"

Input types

Type	Description
string	Free text
boolean	Checkbox
choice	Dropdown list
environment	Environment selector

repository_dispatch

# Déclenché par API externe
on:
  repository_dispatch:
    types: [deploy, build]

jobs:
  handle:
    runs-on: ubuntu-latest
    steps:
      - run: |
          echo "Event: ${{ github.event.action }}"
          echo "Payload: ${{ toJSON(github.event.client_payload) }}"

# Déclencher via API
curl -X POST \
  -H "Authorization: token $GITHUB_TOKEN" \
  -H "Accept: application/vnd.github.v3+json" \
  https://api.github.com/repos/OWNER/REPO/dispatches \
  -d '{"event_type":"deploy","client_payload":{"env":"prod"}}'

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6 - Practical exercises

Exercise 1: CI on PR

Create a workflow that runs on PRs to main:

Solution

name: PR Check

on:
  pull_request:
    branches: [main]
    types: [opened, synchronize, reopened]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: npm test

Exercise 2: Manual deployment

Create a workflow with an environment choice:

Solution

name: Manual Deploy

on:
  workflow_dispatch:
    inputs:
      environment:
        type: choice
        options: [staging, production]
        required: true

jobs:
  deploy:
    runs-on: ubuntu-latest
    steps:
      - run: echo "Deploying to ${{ inputs.environment }}"

Quiz

Q1. Which event allows triggering via API?

Answer

repository_dispatch

Q2. Which time zone does the schedule use?

Answer

UTC

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Key takeaways

• push and pull_request for standard CI
• Filter by branches, tags, paths
• schedule with cron syntax (UTC)
• workflow_dispatch for manual triggering
• repository_dispatch for external API
• workflow_run to chain workflows
• pull_request_target: watch out for security!

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