Dynamically start crd controller (#574)

Signed-off-by: Tamal Saha <[email protected]>

apiextensions/controller.go

@@ -0,0 +1,87 @@
+/*
+Copyright AppsCode Inc. and Contributors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package apiextensions
+
+import (
+	"context"
+	"sync"
+
+	apiextensions "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	ctrl "sigs.k8s.io/controller-runtime"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/log"
+)
+
+type SetupFn func(ctx context.Context, mgr ctrl.Manager)
+
+var setupFns = map[schema.GroupKind]SetupFn{
+	// schema.GroupKind{"compute.gcp.kubedb.com", "Firewall"}:                 firewall.Setup,
+}
+
+var (
+	setupDone = map[schema.GroupKind]bool{}
+	mu        sync.Mutex
+)
+
+type Reconciler struct {
+	ctx context.Context
+	mgr ctrl.Manager
+}
+
+func NewReconciler(ctx context.Context, mgr ctrl.Manager) *Reconciler {
+	return &Reconciler{ctx: ctx, mgr: mgr}
+}
+
+func (r *Reconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
+	log := log.FromContext(ctx)
+	var crd apiextensions.CustomResourceDefinition
+	if err := r.mgr.GetClient().Get(ctx, req.NamespacedName, &crd); err != nil {
+		log.Error(err, "unable to fetch CustomResourceDefinition")
+		return ctrl.Result{}, client.IgnoreNotFound(err)
+	}
+
+	gk := schema.GroupKind{
+		Group: crd.Spec.Group,
+		Kind:  crd.Spec.Names.Kind,
+	}
+	mu.Lock()
+	defer mu.Unlock()
+	_, found := setupDone[gk]
+	if found {
+		return ctrl.Result{}, nil
+	}
+	setup, found := setupFns[gk]
+	if found {
+		setup(r.ctx, r.mgr)
+		setupDone[gk] = true
+	}
+	return ctrl.Result{}, nil
+}
+
+func (r *Reconciler) SetupWithManager(mgr ctrl.Manager) error {
+	return ctrl.NewControllerManagedBy(mgr).
+		For(&apiextensions.CustomResourceDefinition{}).
+		Complete(r)
+}
+
+func RegisterSetup(gk schema.GroupKind, fn SetupFn) {
+	mu.Lock()
+	defer mu.Unlock()
+
+	setupFns[gk] = fn
+}