How to setup webhook with Jenkins

• What is a webhook?
• Gitea Plugin on Jenkins (only for Jenkins admins)
• Build project configuration
• Webhook on the Gitea repository
• Testing the Gitea/Jenkins round trip

#What is a webhook?

A webhook is a mechanism to automatically trigger the build of a Jenkins project upon a commit pushed in a Git repository.

This guide details the steps to have Jenkins automatically create a build if it detects changes to a Gitea repository. This can be a very useful improvement to continuous integration setup with Jenkins because this method is only telling Jenkins to attempt a new build when a change is detected rather than polling on an interval, which can be a very inefficient.

#Gitea Plugin on Jenkins (only for Jenkins admins)

This plugin allows to configure Jenkins to talk to Gitea.

Installation

In Jenkins: download and install the Gitea plugin in Jenkins.

Go in the page: Manage Jenkins -> Manage Plugins -> Available -> Gitea plugin

And install the plugin.

Configuration

Go in the page: Manage Jenkins -> Configure System -> Gitea Servers:

#Build project configuration

In Jenkins, under the project settings page "Source Code Management":

• set option to "Git",
• provide URL to your repo (e.g. https://code-repo.example.org/troy/gxRest.git),
• set the credentials to git.gcube (only if the repository is NOT public),
• specify */master as branch to build,

and in "Build Triggers" section:

• check "Poll SCM" option with no schedule defined. This setup basically tells Jenkins to poll your Gitea repo only when requested via the webhook.

#Webhook on the Gitea repository

In Gitea, under repo -> Settings -> Webhooks:

• click on "Add Webhook",
• select "Gitea" in the drop down list

In the Webhook form:

• set the URL to [https://jenkins.example.org/gitea-webhook/post?job=project](https://jenkins.example.org/gitea-webhook/post?job=project), where project is the name of the project in Jenkins to build,
• set post content type to "application/json",
• check "Push Events" for the Trigger On option,
• clear the secret (leave it blank).

Do note that

1. the value of the job option is case-sensitive (in the example, gxrest instead of gxRest would fail).
2. HTTPS is needed to send a POST request

At this point clicking on "Test Delivery" button should produce a successful delivery attempt (green checkmark, as shown in the figure).

If the test deliveries fail, try to see if you can POST to Jenkins webhook URL ([http://jenkins.example.org/gitea-webhook/post](http://jenkins.example.org/gitea-webhook/post)). E.g. using Postman or with curl:

curl -vvv -H "Content-Type: application/json" -H "X-Gitea-Event: push" -X POST http://jenkins.example.org/gitea-webhook/post -d "{}"

Correct response should be just plain "Processed" string. If you get something else, post it here.

#Testing the Gitea/Jenkins round trip

1. We push a new commit with a message "Update README.md" in the Gitea repository:

2. If the webhook has been properly set up, on the Jenkins interface we should see that the build of the linked project has started:

3. Clicking on the ongoing build, we can appreciate that it has been triggered by the commit:

4. Projects configured downstream will be also built if the build completes successfully.