Sengrok - serverless self-hosted ngrok-like service

Why?

Testing webhook integrations is a tedious process. We'd better use CI for that.
Guess what? ngrok and friends do not really work in CI environments.
Mainly because these tools produce a random url each time you run them.
And the majority of public webhooks cannot be programmatically configured with a new url each time you launch a CI test.

How?

sengrok is a fully serverless solution, built on AWS.
The architecture is pretty simple:

flowchart TD
    subgraph aws ["AWS Account"]
        webhook["Webhook lambda"]
        ws-server["Websocket lambda"]
        api-gw["API Gateway"]
        api-gw <--> ws-server
        api-gw <--> webhook
    end
    subgraph wh ["Webhook Service"]
        emitter["event emitter"]
        emitter ---> webhook
    end
    subgraph client ["Client"]
        local["Local listener"]
        sengrok["Sengrok"]
        sengrok --> local
        sengrok <--> ws-server
    end

Webhook lambda listens for events from a public webhook.
sengrock local executable connects to a websocket lambda and issues subscribe command for some webhook route.
Once subscribed it will receive all events from that webhook route and then forward it to your local listener of choice.

To try

You will need a modern Node.js environment (18.x) and an AWS account credentials with sufficient permissions

git clone https://github.com/pkit/sengrok
yarn
yarn deploy

Output of deploy would look like:

Deploying sengrok to stage dev (us-east-2)
✔ serverless-better-credentials: credentials resolved from config ini profile: AWS_PROFILE (default)
Bundling with Webpack...
No external modules needed
Copying existing artifacts...

✔ Service deployed to stack sengrok-dev (35s)

endpoints:
  wss://xxxxx.execute-api.us-east-2.amazonaws.com/dev
  POST - https://yyyyyy.execute-api.us-east-2.amazonaws.com/{proxy+}
functions:
  webhookListener: sengrok-dev-webhookListener (860 kB)
  clientWebsocket: sengrok-dev-clientWebsocket (860 kB)

We are interested in the wss:// url.

./sengrok forward wss://xxxxx.execute-api.us-east-2.amazonaws.com/dev /github http://localhost:3000

The command above will connect to the deployed service and forward all /github events to http://localhost:3000

Now you can set up the webhook in actual GitHub using the second URL from above (and the route /github):

https://yyyyyy.execute-api.us-east-2.amazonaws.com/github

Configuring another webhook doesn't require deploying anything again.

Just add some other route to the webhook you're interested in:

https://yyyyyy.execute-api.us-east-2.amazonaws.com/another/webhook/route

And start another sengrok listener.
That one will forward /another/webhook to http://localhost:3001/events

./sengrok forward wss://xxxxx.execute-api.us-east-2.amazonaws.com/dev /another/webhook/route http://localhost:3001/events

FAQ

• How to use another region?
  By default, deploy script uses us-east-2.
  To select another region run: yarn deploy --region us-west-2

• How to deploy multiple listeners to the same webhook?
  Just run another sengrok with the same arguments.
  All events will be broadcast to all the subscribers.

• How to un-deploy?
  To un-deploy run: yarn remove --region us-east-2