Merge pull request #50467 from freehan/local-cloud-provider

pkg/cloudprovider/providers/gce/BUILD

@@ -13,6 +13,7 @@ go_library(
         "gce.go",
         "gce_addresses.go",
         "gce_addresses_fakes.go",
+        "gce_alpha.go",
         "gce_annotations.go",
         "gce_backendservice.go",
         "gce_cert.go",

pkg/cloudprovider/providers/gce/gce.go

@@ -118,6 +118,11 @@ type GCECloud struct {
 	// lock to prevent shared resources from being prematurely deleted while the operation is
 	// in progress.
 	sharedResourceLock sync.Mutex
+	// AlphaFeatureGate gates gce alpha features in GCECloud instance.
+	// Related wrapper functions that interacts with gce alpha api should examine whether
+	// the corresponding api is enabled.
+	// If not enabled, it should return error.
+	AlphaFeatureGate *AlphaFeatureGate
 }
 
 type ServiceManager interface {
@@ -151,6 +156,9 @@ type ConfigFile struct {
 		// Specifying ApiEndpoint will override the default GCE compute API endpoint.
 		ApiEndpoint string `gcfg:"api-endpoint"`
 		LocalZone   string `gcfg:"local-zone"`
+		// Possible values: List of api names separated by comma. Default to none.
+		// For example: MyFeatureFlag
+		AlphaFeatures []string `gcfg:"alpha-features"`
 	}
 }
 
@@ -167,6 +175,7 @@ type CloudConfig struct {
 	NodeInstancePrefix string
 	TokenSource        oauth2.TokenSource
 	UseMetadataServer  bool
+	AlphaFeatureGate   *AlphaFeatureGate
 }
 
 func init() {
@@ -245,6 +254,12 @@ func generateCloudConfig(configFile *ConfigFile) (cloudConfig *CloudConfig, err
 
 		cloudConfig.NodeTags = configFile.Global.NodeTags
 		cloudConfig.NodeInstancePrefix = configFile.Global.NodeInstancePrefix
+
+		alphaFeatureGate, err := NewAlphaFeatureGate(configFile.Global.AlphaFeatures)
+		if err != nil {
+			glog.Errorf("Encountered error for creating alpha feature gate: %v", err)
+		}
+		cloudConfig.AlphaFeatureGate = alphaFeatureGate
 	}
 
 	// retrieve projectID and zone
@@ -398,6 +413,7 @@ func CreateGCECloud(config *CloudConfig) (*GCECloud, error) {
 		nodeInstancePrefix:       config.NodeInstancePrefix,
 		useMetadataServer:        config.UseMetadataServer,
 		operationPollRateLimiter: operationPollRateLimiter,
+		AlphaFeatureGate:         config.AlphaFeatureGate,
 	}
 
 	gce.manager = &GCEServiceManager{gce}

pkg/cloudprovider/providers/gce/gce_alpha.go

+/*
+Copyright 2017 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 gce
+
+import (
+	"fmt"
+
+	utilerrors "k8s.io/apimachinery/pkg/util/errors"
+)
+
+// All known alpha features
+var knownAlphaFeatures = map[string]bool{}
+
+type AlphaFeatureGate struct {
+	features map[string]bool
+}
+
+func (af *AlphaFeatureGate) Enabled(key string) bool {
+	return af.features[key]
+}
+
+func NewAlphaFeatureGate(features []string) (*AlphaFeatureGate, error) {
+	errList := []error{}
+	featureMap := make(map[string]bool)
+	for _, name := range features {
+		if _, ok := knownAlphaFeatures[name]; !ok {
+			errList = append(errList, fmt.Errorf("alpha feature %q is not supported.", name))
+		} else {
+			featureMap[name] = true
+		}
+	}
+	return &AlphaFeatureGate{featureMap}, utilerrors.NewAggregate(errList)
+}