address comments during review

Signed-off-by: Davanum Srinivas <davanum@gmail.com>

cmd/kube-controller-manager/app/plugins.go

@@ -38,6 +38,7 @@ import (
 	"k8s.io/kubernetes/pkg/volume/nfs"
 	volumeutil "k8s.io/kubernetes/pkg/volume/util"
 
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	persistentvolumeconfig "k8s.io/kubernetes/pkg/controller/volume/persistentvolume/config"
 	"k8s.io/utils/exec"
 )
@@ -47,7 +48,12 @@ import (
 // The list of plugins is manually compiled. This code and the plugin
 // initialization code for kubelet really, really need a through refactor.
 func ProbeAttachableVolumePlugins(logger klog.Logger) ([]volume.VolumePlugin, error) {
+	var err error
 	allPlugins := []volume.VolumePlugin{}
+	allPlugins, err = appendAttachableLegacyProviderVolumes(logger, allPlugins, utilfeature.DefaultFeatureGate)
+	if err != nil {
+		return allPlugins, err
+	}
 	allPlugins = append(allPlugins, fc.ProbeVolumePlugins()...)
 	allPlugins = append(allPlugins, iscsi.ProbeVolumePlugins()...)
 	allPlugins = append(allPlugins, csi.ProbeVolumePlugins()...)
@@ -63,7 +69,12 @@ func GetDynamicPluginProber(config persistentvolumeconfig.VolumeConfiguration) v
 
 // ProbeExpandableVolumePlugins returns volume plugins which are expandable
 func ProbeExpandableVolumePlugins(logger klog.Logger, config persistentvolumeconfig.VolumeConfiguration) ([]volume.VolumePlugin, error) {
+	var err error
 	allPlugins := []volume.VolumePlugin{}
+	allPlugins, err = appendExpandableLegacyProviderVolumes(logger, allPlugins, utilfeature.DefaultFeatureGate)
+	if err != nil {
+		return allPlugins, err
+	}
 	allPlugins = append(allPlugins, fc.ProbeVolumePlugins()...)
 	return allPlugins, nil
 }
@@ -105,6 +116,13 @@ func ProbeControllerVolumePlugins(logger klog.Logger, config persistentvolumecon
 		klog.FlushAndExit(klog.ExitFlushTimeout, 1)
 	}
 	allPlugins = append(allPlugins, nfs.ProbeVolumePlugins(nfsConfig)...)
+
+	var err error
+	allPlugins, err = appendExpandableLegacyProviderVolumes(logger, allPlugins, utilfeature.DefaultFeatureGate)
+	if err != nil {
+		return allPlugins, err
+	}
+
 	allPlugins = append(allPlugins, local.ProbeVolumePlugins()...)
 	allPlugins = append(allPlugins, csi.ProbeVolumePlugins()...)
 

cmd/kube-controller-manager/app/plugins_providers.go

@@ -0,0 +1,77 @@
+/*
+Copyright 2019 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 app
+
+import (
+	"k8s.io/component-base/featuregate"
+	"k8s.io/csi-translation-lib/plugins"
+	"k8s.io/klog/v2"
+	"k8s.io/kubernetes/pkg/features"
+	"k8s.io/kubernetes/pkg/volume"
+	"k8s.io/kubernetes/pkg/volume/csimigration"
+	"k8s.io/kubernetes/pkg/volume/portworx"
+	"k8s.io/kubernetes/pkg/volume/rbd"
+)
+
+type probeFn func() []volume.VolumePlugin
+
+func appendPluginBasedOnFeatureFlags(logger klog.Logger, plugins []volume.VolumePlugin, inTreePluginName string, featureGate featuregate.FeatureGate, pluginInfo pluginInfo) ([]volume.VolumePlugin, error) {
+
+	_, err := csimigration.CheckMigrationFeatureFlags(featureGate, pluginInfo.pluginMigrationFeature, pluginInfo.pluginUnregisterFeature)
+	if err != nil {
+		logger.Error(err, "Unexpected CSI Migration Feature Flags combination detected. CSI Migration may not take effect")
+		klog.FlushAndExit(klog.ExitFlushTimeout, 1)
+		// TODO: fail and return here once alpha only tests can set the feature flags for a plugin correctly
+	}
+
+	// Skip appending the in-tree plugin to the list of plugins to be probed/initialized
+	// if the plugin unregister feature flag is set
+	if featureGate.Enabled(pluginInfo.pluginUnregisterFeature) {
+		logger.Info("Skip registration of plugin since feature flag is enabled", "plugin", inTreePluginName, "feature", pluginInfo.pluginUnregisterFeature)
+		return plugins, nil
+	}
+	plugins = append(plugins, pluginInfo.pluginProbeFunction()...)
+	return plugins, nil
+}
+
+type pluginInfo struct {
+	pluginMigrationFeature  featuregate.Feature
+	pluginUnregisterFeature featuregate.Feature
+	pluginProbeFunction     probeFn
+}
+
+func appendAttachableLegacyProviderVolumes(logger klog.Logger, allPlugins []volume.VolumePlugin, featureGate featuregate.FeatureGate) ([]volume.VolumePlugin, error) {
+	pluginMigrationStatus := make(map[string]pluginInfo)
+	pluginMigrationStatus[plugins.PortworxVolumePluginName] = pluginInfo{pluginMigrationFeature: features.CSIMigrationPortworx, pluginUnregisterFeature: features.InTreePluginPortworxUnregister, pluginProbeFunction: portworx.ProbeVolumePlugins}
+	pluginMigrationStatus[plugins.RBDVolumePluginName] = pluginInfo{pluginMigrationFeature: features.CSIMigrationRBD, pluginUnregisterFeature: features.InTreePluginRBDUnregister, pluginProbeFunction: rbd.ProbeVolumePlugins}
+	var err error
+	for pluginName, pluginInfo := range pluginMigrationStatus {
+		allPlugins, err = appendPluginBasedOnFeatureFlags(logger, allPlugins, pluginName, featureGate, pluginInfo)
+		if err != nil {
+			return allPlugins, err
+		}
+	}
+	return allPlugins, nil
+}
+
+func appendExpandableLegacyProviderVolumes(logger klog.Logger, allPlugins []volume.VolumePlugin, featureGate featuregate.FeatureGate) ([]volume.VolumePlugin, error) {
+	return appendLegacyProviderVolumes(logger, allPlugins, featureGate)
+}
+
+func appendLegacyProviderVolumes(logger klog.Logger, allPlugins []volume.VolumePlugin, featureGate featuregate.FeatureGate) ([]volume.VolumePlugin, error) {
+	return appendAttachableLegacyProviderVolumes(logger, allPlugins, featureGate)
+}