wormhole/DEVELOP.md

# Developing the bridge

## Local Devnet

The following dependencies are required for local development:

- [Go](https://golang.org/dl/) >= 1.16.5
- [Docker](https://docs.docker.com/engine/install/) / moby-engine >= 19.03
- [Tilt](http://tilt.dev/) >= 0.20.8
- [NodeJS/npm](https://nodejs.org/en/download/) >= 14
- Any of the local Kubernetes clusters supported by Tilt.
  We recommend [minikube](https://kubernetes.io/docs/setup/learning-environment/minikube/) >= v1.21.0 with the kvm2 driver.

See the [Tilt docs](https://docs.tilt.dev/install.html) docs on how to set up your local cluster -
it won't take more than a few minutes to set up! Example minikube invocation, adjust limits as needed:

    minikube start --cpus=8 --memory=8G --disk-size=50G --driver=kvm2

npm wants to set up an insane number of inotify watches in the web container which may exceed kernel limits.
The minikube default is too low, adjust it like this:

    minikube ssh 'echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf && sudo sysctl -p'

This should work on Linux, MacOS and possibly even Windows.

By default, the devnet is deployed to the `wormhole` namespace rather than `default`. This makes it easy to clean up the
entire deployment by simply removing the namespace, which isn't possible with `default`. Change your default namespace
to avoid having to specify `-n wormhole` for all commands:

    kubectl config set-context --current --namespace=wormhole

After installing all dependencies, just run `tilt up`.
Whenever you modify a file, the devnet is automatically rebuilt and a rolling update is done.

Launch the devnet while specifying the number of guardians nodes to run (default is five):

    tilt up -- --num=1

If you want to work on non-consensus parts of the code, running with a single guardian is easiest since
you won't have to wait for k8s to restart all pods.

## Usage

Watch pod status in your cluster:

    kubectl get pod -A -w

Get logs for single guardian node:

    kubectl logs guardian-0

Restart a specific pod:

    kubectl delete pod guardian-0

Adjust number of nodes in running cluster: (this is only useful if you want to test scenarios where the number
of nodes diverges from the guardian set - otherwise, `tilt down --delete-namespaces` and restart the cluster)

    tilt args -- --num=2

Tear down cluster:

    tilt down --delete-namespaces

Once you're done, press Ctrl-C. Run `tilt down` to tear down the devnet.