Sep 2, 2019 • Mikolaj Gasior

Context

Here’s the situation. Jenkins is available internally in the company network only. However, its Multibranch Pipeline job must be triggered when a push on branch happens. And the repository is in GitHub.

A Webhook to a GitHub repository, which basically is a URL of a public endpoint in the company that would receive notification on specific events, like the one we are interested in. These events must trigger jenkins jobs by sending payload to its API.

Hence, a simple application that works as an adapter is necessary. One that will receive payload from GitHub and send payload to Jenkins, and obviously it requires access to internal company network.

Implementation

Sample application can be found here. The code is a bit old but some snippets might be useful.

Running

Check README to get information on how to use the application.

Source code

Let’s just go through it quickly.

1. Application starts an HTTP daemon that listens for GitHub payload, here.
2. Once an event is received (and it’s not just a ping), it is processed here.
3. A call to Jenkins API requires getting so-called Crumb before making a POST request to its API, and the snippet doing that is here and here.