What are webhooks in the CI/CD process?

Webhooks in CI/CD are an automated way to notify the CI/CD system (e.g., Jenkins, GitLab CI, GitHub Actions) about events in an external system (e.g., a Git repository).

Workflow:

1. The external system (e.g., GitHub) registers an event (e.g., push to a specific branch).
2. When the event occurs, the external system sends an HTTP POST request (webhook) to a predefined URL of the CI/CD system.
3. The CI/CD system receives the request, analyzes its content (often in JSON format), and initiates the appropriate action, such as starting a pipeline.

Advantages of using webhooks in CI/CD:

• Automation: Pipeline runs immediately after the event occurs without manual intervention or periodic polling.
• Responsiveness: The CI/CD system reacts promptly to changes, speeding up the development cycle.
• Efficiency: Not having to constantly poll the external system reduces load and traffic.

Example of configuring a webhook in GitHub for Jenkins:

In the GitHub repository settings (Settings -> Webhooks):

• Payload URL: http://your_jenkins_server:8080/github-webhook/ (or a similar URL provided by the plugin)
• Content type: application/json
• Secret (optional): A key for request verification.
• Which events would you like to trigger this webhook? Select the necessary events, e.g., Pushes.

In Jenkins (Job Configuration -> Build Triggers):

• Check the option "GitHub hook trigger for GITScm polling".

Thus, every push to the GitHub repository will send a webhook that triggers the corresponding Job in Jenkins.