Merge pull request #2359 from sedefsavas/featuregate

✨Adding feature-gate flag for experimental features (and migrating from go flags to pflags)

Author: k8s-ci-robot

features/features.go

@@ -0,0 +1,43 @@
+/*
+Copyright 2020 The Kubernetes 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 features
+
+import (
+	"k8s.io/apimachinery/pkg/util/runtime"
+	"k8s.io/component-base/featuregate"
+
+	utilfeature "sigs.k8s.io/cluster-api/util/featuregate"
+)
+
+const (
+// Every feature gate should add method here following this template:
+//
+// // owner: @username
+// // alpha: v1.X
+// MyFeature featuregate.Feature = "MyFeature"
+)
+
+func init() {
+	runtime.Must(utilfeature.DefaultMutableFeatureGate.Add(defaultClusterAPIFeatureGates))
+}
+
+// defaultClusterAPIFeatureGates consists of all known cluster-api-specific feature keys.
+// To add a new feature, define a key for it above and add it here.
+var defaultClusterAPIFeatureGates = map[featuregate.Feature]featuregate.FeatureSpec{
+	// Every feature should be initiated here:
+	// MyFeature:     {Default: false, PreRelease: featuregate.Alpha},
+}

go.mod

@@ -22,6 +22,7 @@ require (
 	github.com/prometheus/client_model v0.0.0-20190129233127-fd36f4220a90
 	github.com/prometheus/procfs v0.0.5 // indirect
 	github.com/spf13/cobra v0.0.5
+	github.com/spf13/pflag v1.0.5
 	github.com/spf13/viper v1.3.2
 	go.etcd.io/etcd v0.0.0-20191023171146-3cf2f69b5738
 	go.uber.org/atomic v1.4.0 // indirect
@@ -39,6 +40,7 @@ require (
 	k8s.io/apiserver v0.17.2
 	k8s.io/client-go v0.17.2
 	k8s.io/cluster-bootstrap v0.0.0-20190516232516-d7d78ab2cfe7
+	k8s.io/component-base v0.17.2
 	k8s.io/klog v1.0.0
 	k8s.io/utils v0.0.0-20191114184206-e782cd3c129f
 	sigs.k8s.io/controller-runtime v0.5.0

go.sum

@@ -498,6 +498,7 @@ k8s.io/client-go v0.17.2/go.mod h1:QAzRgsa0C2xl4/eVpeVAZMvikCn8Nm81yqVx3Kk9XYI=
 k8s.io/cluster-bootstrap v0.0.0-20190516232516-d7d78ab2cfe7 h1:5wvjieVoU4oovHlkeD256q2M2YYi2P01zk6wxSR2zk0=
 k8s.io/cluster-bootstrap v0.0.0-20190516232516-d7d78ab2cfe7/go.mod h1:iBSm2nwo3OaiuW8VDvc3ySDXK5SKfUrxwPvBloKG7zg=
 k8s.io/code-generator v0.17.2/go.mod h1:DVmfPQgxQENqDIzVR2ddLXMH34qeszkKSdH/N+s+38s=
+k8s.io/component-base v0.17.2 h1:0XHf+cerTvL9I5Xwn9v+0jmqzGAZI7zNydv4tL6Cw6A=
 k8s.io/component-base v0.17.2/go.mod h1:zMPW3g5aH7cHJpKYQ/ZsGMcgbsA/VyhEugF3QT1awLs=
 k8s.io/gengo v0.0.0-20190128074634-0689ccc1d7d6/go.mod h1:ezvh/TsK7cY6rbqRK0oQQ8IAqLxYwwyPxAX1Pzy0ii0=
 k8s.io/gengo v0.0.0-20190822140433-26a664648505/go.mod h1:ezvh/TsK7cY6rbqRK0oQQ8IAqLxYwwyPxAX1Pzy0ii0=

main.go

@@ -22,12 +22,15 @@ import (
 	"os"
 	"time"
 
+	"github.com/spf13/pflag"
 	apiextensionsv1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
 	"k8s.io/client-go/rest"
 	"k8s.io/klog"
 	"k8s.io/klog/klogr"
+	_ "sigs.k8s.io/cluster-api/features"
+	"sigs.k8s.io/cluster-api/util/featuregate"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/cache"
 	"sigs.k8s.io/controller-runtime/pkg/client"
@@ -69,44 +72,52 @@ func init() {
 	// +kubebuilder:scaffold:scheme
 }
 
-func main() {
-	flag.StringVar(&metricsAddr, "metrics-addr", ":8080",
+// InitFlags initializes the flags.
+func InitFlags(fs *pflag.FlagSet) {
+	fs.StringVar(&metricsAddr, "metrics-addr", ":8080",
 		"The address the metric endpoint binds to.")
 
-	flag.BoolVar(&enableLeaderElection, "enable-leader-election", false,
+	fs.BoolVar(&enableLeaderElection, "enable-leader-election", false,
 		"Enable leader election for controller manager. Enabling this will ensure there is only one active controller manager.")
 
-	flag.StringVar(&watchNamespace, "namespace", "",
+	fs.StringVar(&watchNamespace, "namespace", "",
 		"Namespace that the controller watches to reconcile cluster-api objects. If unspecified, the controller watches for cluster-api objects across all namespaces.")
 
-	flag.StringVar(&profilerAddress, "profiler-address", "",
+	fs.StringVar(&profilerAddress, "profiler-address", "",
 		"Bind address to expose the pprof profiler (e.g. localhost:6060)")
 
-	flag.IntVar(&clusterConcurrency, "cluster-concurrency", 10,
+	fs.IntVar(&clusterConcurrency, "cluster-concurrency", 10,
 		"Number of clusters to process simultaneously")
 
-	flag.IntVar(&machineConcurrency, "machine-concurrency", 10,
+	fs.IntVar(&machineConcurrency, "machine-concurrency", 10,
 		"Number of machines to process simultaneously")
 
-	flag.IntVar(&machineSetConcurrency, "machineset-concurrency", 10,
+	fs.IntVar(&machineSetConcurrency, "machineset-concurrency", 10,
 		"Number of machine sets to process simultaneously")
 
-	flag.IntVar(&machineDeploymentConcurrency, "machinedeployment-concurrency", 10,
+	fs.IntVar(&machineDeploymentConcurrency, "machinedeployment-concurrency", 10,
 		"Number of machine deployments to process simultaneously")
 
-	flag.IntVar(&machinePoolConcurrency, "machinepool-concurrency", 10,
+	fs.IntVar(&machinePoolConcurrency, "machinepool-concurrency", 10,
 		"Number of machine pools to process simultaneously")
 
-	flag.DurationVar(&syncPeriod, "sync-period", 10*time.Minute,
+	fs.DurationVar(&syncPeriod, "sync-period", 10*time.Minute,
 		"The minimum interval at which watched resources are reconciled (e.g. 15m)")
 
-	flag.IntVar(&webhookPort, "webhook-port", 0,
+	fs.IntVar(&webhookPort, "webhook-port", 0,
 		"Webhook Server port, disabled by default. When enabled, the manager will only work as webhook server, no reconcilers are installed.")
 
-	flag.StringVar(&healthAddr, "health-addr", ":9440",
+	fs.StringVar(&healthAddr, "health-addr", ":9440",
 		"The address the health endpoint binds to.")
 
-	flag.Parse()
+	// Add --feature-gates flag
+	featuregate.DefaultMutableFeatureGate.AddFlag(fs)
+}
+
+func main() {
+	InitFlags(pflag.CommandLine)
+	pflag.CommandLine.AddGoFlagSet(flag.CommandLine)
+	pflag.Parse()
 
 	ctrl.SetLogger(klogr.New())
 

util/featuregate/featuregate.go

@@ -0,0 +1,33 @@
+/*
+Copyright 2020 The Kubernetes 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 featuregate
+
+import (
+	"k8s.io/component-base/featuregate"
+)
+
+var (
+	// DefaultMutableFeatureGate is a mutable version of DefaultFeatureGate.
+	// Only top-level commands/options setup and the k8s.io/component-base/featuregate/testing package should make use of this.
+	// Tests that need to modify featuregate gates for the duration of their test should use:
+	//   defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.<FeatureName>, <value>)()
+	DefaultMutableFeatureGate featuregate.MutableFeatureGate = featuregate.NewFeatureGate()
+
+	// DefaultFeatureGate is a shared global FeatureGate.
+	// Top-level commands/options setup that needs to modify this featuregate gate should use DefaultMutableFeatureGate.
+	DefaultFeatureGate featuregate.FeatureGate = DefaultMutableFeatureGate
+)