What is a webhook, and how does it connect GitHub to your CI?
CI/CD & GitOps · Advanced level
Answer
A webhook is an HTTP callback sent by GitHub when an event occurs, such as push, pull_request, tag creation, or release. Jenkins or another CI system receives the event, verifies it, and starts the matching pipeline quickly without polling.
Technical explanation
Git history is both collaboration state and audit evidence, so choose merge, rebase, revert, and reset based on whether history is shared.
Short-lived branches reduce merge conflicts and make CI feedback meaningful; long-lived branches increase drift and integration risk.
Tags, release branches, signed commits, and changelogs connect source history to released artifacts and operational traceability.
Prefer safe, reviewable operations on shared branches: revert bad changes, open PRs for backports, and avoid force-pushes unless the team explicitly coordinates them.
Hands-on example
1. Practice the Git operation for: What is a webhook, and how does it connect GitHub to your CI in a throwaway repository with main, feature, release, and hotfix branches.
2. Configure a GitHub webhook for push and pull_request events, set a shared secret, expose the CI endpoint, and verify the received payload signature before triggering the job.
3. Inspect the result with git log --oneline --graph --decorate --all and verify whether history was preserved, replayed, tagged, or safely undone.
4. Push through a pull request with required CI checks, run tests after conflict resolution or cherry-pick, and document why that operation was chosen.
5. For release scenarios, build from a signed tag, publish the artifact with the commit SHA and version, and confirm the release notes match the merged changes.
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