What are webhooks in the CI/CD process?

Webhooks in CI/CD are automated HTTP POST requests sent from one application to another when a specific event occurs.

In the context of CI/CD, they act as triggers. For example, on a push event in a Git repository, a webhook sends a notification to the CI/CD system (Jenkins, GitLab CI, GitHub Actions, etc.). Upon receiving the notification, this system automatically starts a pipeline (build, test, deployment).

Main components:

• Event source: The system where the event occurs (e.g., Git repository).
• Webhook URI: The URL to which the HTTP POST request is sent. This address belongs to the receiving system (CI/CD).
• Payload: Data about the event, transmitted in the body of the HTTP POST request (e.g., commit information, branch).
• Receiving system: The CI/CD system that processes the webhook and initiates actions.

Advantages of using:

• Automation: Eliminates manual process initiation.
• Reactivity: The pipeline starts immediately after the event, providing faster feedback.
• Low load: The receiving system does not need to poll the source constantly.

Example of working with GitHub Actions:

1. A webhook is added in the GitHub repository settings, pointing to the GitHub Actions endpoint.
2. The developer performs a git push.
3. GitHub, detecting the push event, sends an HTTP POST request (webhook) to the specified GitHub Actions endpoint.
4. GitHub Actions receives the webhook, analyzes the payload, and triggers the corresponding workflow.

# Example workflow in GitHub Actions triggered by push

name: CI Pipeline

on:
  push:
    branches:
      - main # Run on push to the main branch

jobs:
  build-and-test:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v2 # Clone the repository

      - name: Setup Node.js
        uses: actions/setup-node@v2
        with:
          node-version: '14'

      - name: Install dependencies
        run: npm ci

      - name: Run tests
        run: npm test