Lighthouse GitHub App

This is a multi-tenant version of Lighthouse for use in the SaaS which implements a GitHub App.

How it works

Here is a diagram of how it works:

You can think of the Lighthouse GitHub App as like the regular Lighthouse - it handles webhooks from github, labels/comments on PRs and triggers pipelines - only it runs in a shared tenant rather than in each consumers cluster.

When the github app is installed to a github user/organisation all github webhooks for all repositories are sent to this HTTP endpoint.

Internally this service then queries the jx-tenant-service's REST API to query the workspaces and Scheduler JSON for the webhooks git URL.

Then for each webhook we:

• query the Workspace + Scheduler rows for the git URL
• for each Workspace + Scheduler:
  • connect to the remote Workspace project (for KubeClient / JXClient / TektonClient etc)
  • turn the Scheduler JSON into a lighthouse Prow configs and plugins configuration object
  • invoke the lighthouse webhook function ProcessWebhook() to either comment on the PR or create a new pipeline in the tenant cluster via the metapipeline client.

Environment variables

The following environment variables are required if you want to run this app locally:

Name	Description
LHA_APP_ID	The GitHub App ID (shown on the Apps page)
LHA_HMAC_TOKEN	The HMAC token to verify webhooks
LHA_PRIVATE_KEY_FILE	The location of the private key file from the GitHub App
BOT_NAME	optional name of the current bot. e.g. myapp[bot]

Building

Run

make build && ./build/lighthouse-githubapp

Debugging in Dev/Staging

Ideally we would add support for Stackdriver Debugging so we can easily debug stuff in production - however this is currently blocked on kaniko having issues building go source & crashing nodes. Until we figure that out, telepresence is a handy tool for debugging as its not always super easy to test out lighthouse-githubapp on a real cluster using real apps.

• install telepresence
• connect to the Dev / Staging cluster where lighthouse-githubapp usually runs
• copy the google service account JSON to the file https://www.telepresence.io/reference/install which is usually inside the secret jenkins-x-lighthouse-githubapp-saas
• start the debugger:

export BOT_NAME="jenkins-x[bot]"    
telepresence --swap-deployment jenkins-x-lighthouse-githubapp --expose 8080 --run dlv --listen=:2345 --headless=true --api-version=2 exec `which lighthouse-githubapp`

• now run the debug in your IDE using the usual remote debug Go option in your IDE. In IDEA/Goland you need to setup a Go Remote using the same port above 2345

When you terminate the process/debug session telepresence will now switch back to the regular deployment again. You can force this to happen via:

sudo killall lighthouse-githubapp
sudo killall dlv