Create a controller

    Example controller:

    1. Generate the components by running the command:

      1. ${CODEGEN_PKG}/generate-groups.sh "deepcopy,client,informer,lister" \
      2.   knative.dev/sample-source/pkg/client knative.dev/sample-source/pkg/apis \
      3.   "samples:v1alpha1" \
      4.   --go-header-file ${REPO_ROOT}/hack/boilerplate/boilerplate.go.txt

    3. Pass the new controller implementation to the sharedmain method:

      1. import (
      2.     // The set of controllers this controller process runs.
      3.     "knative.dev/sample-source/pkg/reconciler/sample"
      4.     // This defines the shared main for injected controllers.
      5.     "knative.dev/pkg/injection/sharedmain"
      6. )
      8. func main() {
      9.     sharedmain.Main("sample-source-controller", sample.NewController)
      10. }

    4. Define the NewController implementation:

    5. Import the base reconciler from the knative.dev/pkg dependency:

      1. import (
      3.     // ...
      4. )

    6. Ensure that the event handlers are being filtered to the correct informers:

      1.     deploymentInformer.Informer().AddEventHandler(cache.FilteringResourceEventHandler{
      2.         FilterFunc: controller.FilterGroupKind(v1alpha1.Kind("SampleSource")),
      3.         Handler:    controller.HandleAll(impl.EnqueueControllerOf),
      4.     })
      6.     sinkBindingInformer.Informer().AddEventHandler(cache.FilteringResourceEventHandler{
      7.         FilterFunc: controller.FilterGroupKind(v1alpha1.Kind("SampleSource")),