Support loading controller configuration from a versioned file

cmd/controller/app/controller.go

@@ -35,6 +35,7 @@ import (
 	"k8s.io/utils/clock"
 
 	"github.com/cert-manager/cert-manager/controller-binary/app/options"
+	config "github.com/cert-manager/cert-manager/internal/apis/config/controller"
 	cmdutil "github.com/cert-manager/cert-manager/internal/cmd/util"
 	"github.com/cert-manager/cert-manager/internal/controller/feature"
 	"github.com/cert-manager/cert-manager/pkg/acme/accounts"
@@ -48,7 +49,7 @@ import (
 	"github.com/cert-manager/cert-manager/pkg/util/profiling"
 )
 
-func Run(opts *options.ControllerOptions, stopCh <-chan struct{}) error {
+func Run(opts *config.ControllerConfiguration, stopCh <-chan struct{}) error {
 	rootCtx, cancelContext := context.WithCancel(cmdutil.ContextWithStopCh(context.Background(), stopCh))
 	defer cancelContext()
 	rootCtx = logf.NewContext(rootCtx, logf.Log, "controller")
@@ -67,7 +68,7 @@ func Run(opts *options.ControllerOptions, stopCh <-chan struct{}) error {
 		return err
 	}
 
-	enabledControllers := opts.EnabledControllers()
+	enabledControllers := options.EnabledControllers(opts)
 	log.Info(fmt.Sprintf("enabled controllers: %s", enabledControllers.List()))
 
 	// Start metrics server
@@ -237,7 +238,7 @@ func Run(opts *options.ControllerOptions, stopCh <-chan struct{}) error {
 
 // buildControllerContextFactory builds a new controller ContextFactory which
 // can build controller contexts for each component.
-func buildControllerContextFactory(ctx context.Context, opts *options.ControllerOptions) (*controller.ContextFactory, error) {
+func buildControllerContextFactory(ctx context.Context, opts *config.ControllerConfiguration) (*controller.ContextFactory, error) {
 	log := logf.FromContext(ctx)
 
 	nameservers := opts.DNS01RecursiveNameservers
@@ -273,7 +274,7 @@ func buildControllerContextFactory(ctx context.Context, opts *options.Controller
 	acmeAccountRegistry := accounts.NewDefaultRegistry()
 
 	ctxFactory, err := controller.NewContextFactory(ctx, controller.ContextOptions{
-		Kubeconfig:         opts.Kubeconfig,
+		Kubeconfig:         opts.KubeConfig,
 		KubernetesAPIQPS:   opts.KubernetesAPIQPS,
 		KubernetesAPIBurst: opts.KubernetesAPIBurst,
 		APIServerHost:      opts.APIServerHost,
@@ -329,7 +330,7 @@ func buildControllerContextFactory(ctx context.Context, opts *options.Controller
 	return ctxFactory, nil
 }
 
-func startLeaderElection(ctx context.Context, opts *options.ControllerOptions, leaderElectionClient kubernetes.Interface, recorder record.EventRecorder, callbacks leaderelection.LeaderCallbacks, healthzAdaptor *leaderelection.HealthzAdaptor) error {
+func startLeaderElection(ctx context.Context, opts *config.ControllerConfiguration, leaderElectionClient kubernetes.Interface, recorder record.EventRecorder, callbacks leaderelection.LeaderCallbacks, healthzAdaptor *leaderelection.HealthzAdaptor) error {
 	// Identity used to distinguish between multiple controller manager instances
 	id, err := os.Hostname()
 	if err != nil {

cmd/controller/app/controller_test.go

@@ -0,0 +1,57 @@
+/*
+Copyright 2021 The cert-manager Authors.
+
+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 app
+
+import (
+	"testing"
+
+	"github.com/cert-manager/cert-manager/controller-binary/app/options"
+)
+
+// Test to ensure flags take precedence over config options.
+func TestControllerConfigFlagPrecedence_FlagsTakePrecedence(t *testing.T) {
+	cfg, err := options.NewControllerConfiguration()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cfg.KubeConfig = "<invalid>"
+	if err := controllerConfigFlagPrecedence(cfg, []string{"--kubeconfig=valid"}); err != nil {
+		t.Fatal(err)
+	}
+
+	if cfg.KubeConfig != "valid" {
+		t.Errorf("unexpected field value %q, expected %q", cfg.KubeConfig, "valid")
+	}
+}
+
+// Test to ensure that when flags are not provided, config provided values are preserved.
+func TestControllerConfigFlagPrecedence_ConfigPersistsWithoutFlags(t *testing.T) {
+	cfg, err := options.NewControllerConfiguration()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cfg.KubeConfig = "valid"
+	if err := controllerConfigFlagPrecedence(cfg, []string{}); err != nil {
+		t.Fatal(err)
+	}
+
+	if cfg.KubeConfig != "valid" {
+		t.Errorf("unexpected field value %q, expected %q", cfg.KubeConfig, "valid")
+	}
+}