Added feature gate mechanism; added topology feature gate

Author: verult

cmd/csi-provisioner/csi-provisioner.go

@@ -17,8 +17,9 @@ limitations under the License.
 package main
 
 import (
-	"flag"
+	goflag "flag"
 	"fmt"
+	flag "github.com/spf13/pflag"
 	"math/rand"
 	"os"
 	"strconv"
@@ -37,6 +38,10 @@ import (
 	"k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/clientcmd"
+	"strings"
+
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	utilflag "k8s.io/apiserver/pkg/util/flag"
 )
 
 var (
@@ -48,6 +53,7 @@ var (
 	volumeNamePrefix     = flag.String("volume-name-prefix", "pvc", "Prefix to apply to the name of a created volume")
 	volumeNameUUIDLength = flag.Int("volume-name-uuid-length", -1, "Truncates generated UUID of a created volume to this length. Defaults behavior is to NOT truncate.")
 	showVersion          = flag.Bool("version", false, "Show version.")
+	featureGates         map[string]bool
 
 	provisionController *controller.ProvisionController
 	version             = "unknown"
@@ -57,9 +63,17 @@ func init() {
 	var config *rest.Config
 	var err error
 
+	flag.Var(utilflag.NewMapStringBool(&featureGates), "feature-gates", "A set of key=value pairs that describe feature gates for alpha/experimental features. "+
+		"Options are:\n"+strings.Join(utilfeature.DefaultFeatureGate.KnownFeatures(), "\n"))
+
+	flag.CommandLine.AddGoFlagSet(goflag.CommandLine)
 	flag.Parse()
 	flag.Set("logtostderr", "true")
 
+	if err := utilfeature.DefaultFeatureGate.SetFromMap(featureGates); err != nil {
+		glog.Fatal(err)
+	}
+
 	if *showVersion {
 		fmt.Println(os.Args[0], version)
 		os.Exit(0)

pkg/controller/controller.go

@@ -50,6 +50,9 @@ import (
 
 	"github.com/container-storage-interface/spec/lib/go/csi/v0"
 	csiclientset "k8s.io/csi-api/pkg/client/clientset/versioned"
+
+	"github.com/kubernetes-csi/external-provisioner/pkg/features"
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
 )
 
 const (
@@ -412,7 +415,8 @@ func (p *csiProvisioner) Provision(options controller.VolumeOptions) (*v1.Persis
 		req.VolumeContentSource = volumeContentSource
 	}
 
-	if driverState.capabilities.Has(PluginCapability_ACCESSIBILITY_CONSTRAINTS) {
+	if driverState.capabilities.Has(PluginCapability_ACCESSIBILITY_CONSTRAINTS) &&
+		utilfeature.DefaultFeatureGate.Enabled(features.Topology) {
 		requirements, err := GenerateAccessibilityRequirements(
 			p.client,
 			p.csiAPIClient,
@@ -539,7 +543,8 @@ func (p *csiProvisioner) Provision(options controller.VolumeOptions) (*v1.Persis
 		},
 	}
 
-	if driverState.capabilities.Has(PluginCapability_ACCESSIBILITY_CONSTRAINTS) {
+	if driverState.capabilities.Has(PluginCapability_ACCESSIBILITY_CONSTRAINTS) &&
+		utilfeature.DefaultFeatureGate.Enabled(features.Topology) {
 		pv.Spec.NodeAffinity = GenerateVolumeNodeAffinity(rep.Volume.AccessibleTopology)
 	}
 

pkg/controller/controller_test.go

@@ -28,6 +28,7 @@ import (
 	"github.com/container-storage-interface/spec/lib/go/csi/v0"
 	"github.com/golang/mock/gomock"
 	"github.com/kubernetes-csi/csi-test/driver"
+	"github.com/kubernetes-csi/external-provisioner/pkg/features"
 	crdv1 "github.com/kubernetes-csi/external-snapshotter/pkg/apis/volumesnapshot/v1alpha1"
 	"github.com/kubernetes-csi/external-snapshotter/pkg/client/clientset/versioned/fake"
 	"github.com/kubernetes-incubator/external-storage/lib/controller"
@@ -38,6 +39,8 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/types"
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	utilfeaturetesting "k8s.io/apiserver/pkg/util/feature/testing"
 	"k8s.io/client-go/kubernetes"
 	fakeclientset "k8s.io/client-go/kubernetes/fake"
 	k8stesting "k8s.io/client-go/testing"
@@ -1502,6 +1505,8 @@ func TestProvisionFromSnapshot(t *testing.T) {
 
 // TestProvisionWithTopology is a basic test of provisioner integration with topology functions.
 func TestProvisionWithTopology(t *testing.T) {
+	defer utilfeaturetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.Topology, true)()
+
 	accessibleTopology := []*csi.Topology{
 		{
 			Segments: map[string]string{

pkg/features/features.go

@@ -0,0 +1,35 @@
+/*
+Copyright 2018 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 utilfeature "k8s.io/apiserver/pkg/util/feature"
+
+const (
+	// owner: @verult
+	// alpha: v0.4
+	Topology utilfeature.Feature = "Topology"
+)
+
+func init() {
+	utilfeature.DefaultFeatureGate.Add(defaultKubernetesFeatureGates)
+}
+
+// defaultKubernetesFeatureGates consists of all known feature keys specific to external-provisioner.
+// To add a new feature, define a key for it above and add it here.
+var defaultKubernetesFeatureGates = map[utilfeature.Feature]utilfeature.FeatureSpec{
+	Topology: {Default: false, PreRelease: utilfeature.Alpha},
+}