5 Time saving things about client-go, I didn't know!

client-go is the official go client for talking to Kubernetes (k8s) APIs.

A while back, I read parts of Programming Kubernetes by Michael Hausenblas & Stefan Schimanski. I learned a whole lot about client-go that still helps me.

1. k8s API is divided into apigroups! Core objects don’t (like pods), everything else is pretty much under an API Group
2. k8s.io/client-go isn’t enough to talk to kubernetes API, you need k8s.io/api and k8s.io/apimachinery too
   • You have to match their versions for it to all work!
   • See the client-go versioning for simple instructions!
3. Kinds map to resources, resources map to HTTP Paths through RESTMappers, Scheme connects a kind and a Resource
4. Almost always use informers instead of watch to watch events, the exception is just watching events to log them, then maybe it doesn’t matter.
   • See the package docs
5. Last but not the least, there’s a fake client! You can use it to test your code!
   • See example!

There are many working examples in the upsteam repo now! Check them out to learn more.