Annotate configmaps with author

main.go

package main

import (
	"context"
	"net/http"
	"os"

	kitlog "github.com/go-kit/kit/log"
	"github.com/lawrencejones/theatre/pkg/signals"

	admissionregistrationv1beta1 "k8s.io/api/admissionregistration/v1beta1"
	corev1 "k8s.io/api/core/v1"
	apitypes "k8s.io/apimachinery/pkg/types"

	_ "k8s.io/client-go/plugin/pkg/client/auth/gcp" // this is required to auth against GCP

	"sigs.k8s.io/controller-runtime/pkg/client/config"
	"sigs.k8s.io/controller-runtime/pkg/manager"
	"sigs.k8s.io/controller-runtime/pkg/webhook"
	"sigs.k8s.io/controller-runtime/pkg/webhook/admission"
	"sigs.k8s.io/controller-runtime/pkg/webhook/admission/builder"
	"sigs.k8s.io/controller-runtime/pkg/webhook/admission/types"
)

var logger = kitlog.NewLogfmtLogger(os.Stderr)

type configmapAnnotator struct {
	mgr manager.Manager
}

func (a *configmapAnnotator) Handle(ctx context.Context, req types.Request) types.Response {
	cfgmap := &corev1.ConfigMap{}
	if err := a.mgr.GetAdmissionDecoder().Decode(req, cfgmap); err != nil {
		admission.ErrorResponse(http.StatusBadRequest, err)
	}

	username := req.AdmissionRequest.UserInfo.Username
	copy := cfgmap.DeepCopy()
	copy.ObjectMeta.Annotations = map[string]string{"author": username}

	logger.Log("username", username, "configmap", cfgmap.Name)

	return admission.PatchResponse(cfgmap, copy)
}

func main() {
	mgr, _ := manager.New(config.GetConfigOrDie(), manager.Options{})

	wh, _ := builder.NewWebhookBuilder().
		Mutating().
		Operations(admissionregistrationv1beta1.Create).
		ForType(&corev1.ConfigMap{}).
		Handlers(&configmapAnnotator{mgr}).
		WithManager(mgr).
		Build()

	svr, _ := webhook.NewServer("author-admission-server", mgr, webhook.ServerOptions{
		CertDir: "/tmp/cert",
		BootstrapOptions: &webhook.BootstrapOptions{
			Secret: &apitypes.NamespacedName{
				Namespace: "theatre-system",
				Name:      "theatre-author-admission-server",
			},
			Service: &webhook.Service{
				Namespace: "theatre-system",
				Name:      "theatre-author-admission-server",
				// Selectors should select the pods that runs this webhook server.
				Selectors: map[string]string{
					"app": "theatre-dev",
				},
			},
		},
	})

	svr.Register(wh)

	ctx, cancel := signals.SetupSignalHandler()
	defer cancel()

	if err := mgr.Start(ctx.Done()); err != nil {
		panic(err)
	}

	// spew.Dump(svr.Register(wh))
	// spew.Dump(svr.InstallWebhookManifests())
}