Github Plugin Webhooks - part 1

calendar Jan 1, 2024 · 2 min read · jenkins ci/cd  ·
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(this post is part of the material I cover in my devops course)

We start our journey towards a full example where we use github webhooks to trigger a build in a single branch pipeline.

The big picture

This is what we want to achieve (see notes below):

Jenkins Webhooks

  • We want to configure GitHub to use webhooks to send notifications about change in repository (git push)
  • Unfortunatelly, my computer connects to the Internet using NAT, so only outgoing connections are allowed.
  • We are going to use smee.io to solve our problem.
    • The smee.io is probably not meant for production, but...
    • You can run the server on your infrastructure, it is just a nodejs program
    • Read more about smee here

Start in the middle - smee.io server

  • browse to smee.io
  • Click on Start a new channel
  • The next web page will show you a Webhook Proxy URL, that you should copy and save.
  • Later on, when we configure GitHub to send webhook, we will use this URL
  • The smee.io site will now receive webhook TCP connections (e.g from GitHub) and refer them to a smee.io client that is connected to our server.
  • ..wait..we have not run any smee.io client yet.

smee.io client

  • A smee.io client is just a simple nodejs javascript program
  • I don't like the idea of installing nodejs on my Jenkins machine, so I am using...a..container!!!
  • New thing:
    My nodejs container should be able to TCP-connect to localhost:8080 OF MY HOST COMPUTER.
  • The new thing is that I'm going to connect this container to the host network (instead of any docker network)
  • Here I do it:
1docker run -it --network host  --restart always node bash

(You may want to create a new image based on node where smee client is already installed and running)

  • Making sure I can connect to Jenkins:
1root@osboxes:/# curl 127.0.0.1:8080
2<html><head><meta http-equiv='refresh' content='1;url=/login?from=%2F'/><script>window.location.replace('/login?from=%2F');</script></head><body style='background-color:white; color:white;'>
3...
4...
  • Now install smee.io client:
1npm install --global smee-client
  • Then, run it:
1smee --url <your smee.io url> --path /github-webhook/ --port 8080
  • It display connection messages.
  • I still have to explain the path I was using here

In the next post I'll explore Github WebHooks, and the GitHub plugin.