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Developing controllers

This documentation goes over the different steps needed to write a new controller from scratch.

Using the controller scaffolding generator

ORC comes with a controller scaffolding tool that does most of the heavy work when writing a new controller. It asks a series of questions, then generates stubs for the API, controller implementation, tests and client code.

To run the scaffolding tool: 

$ go run ./cmd/scaffold-controller

The tool can be run either interactively, if you don't pass it any option, or non-interactively if you pass it the -interactive=false flag and provide all of the required flags.

Once the tool returned successfully, there are still a few manual steps to integrate your new controller in ORC:

  • Add the new resource to cmd/resource-generator/main.go and run make generate.
  • Add the new client to internal/scope/scope.go, internal/scope/provider.go, and internal/scope/mock.go.
  • Add the controller to cmd/manager/main.go.
  • Implement all the TODOs. Search the code for TODO(scaffolding) to find them all.
  • Iterate on your controller and get all the tests running.
  • Run make generate-bundle to generate the OLM bundle manifests.
  • Update the README.md file to list the new controller.

The following pages go into the details for writing controllers.