Feature flag to enable/disable canary + optional prometheus install (#937)

controller/config.go

@@ -0,0 +1,65 @@
+/*
+Copyright 2018 The Fission 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 controller
+
+import (
+	"context"
+	"fmt"
+
+	log "github.com/sirupsen/logrus"
+	"k8s.io/client-go/kubernetes"
+
+	"github.com/fission/fission/canaryconfigmgr"
+	"github.com/fission/fission/crd"
+	config "github.com/fission/fission/featureconfig"
+)
+
+func ConfigCanaryFeature(context context.Context, fissionClient *crd.FissionClient, kubeClient *kubernetes.Clientset, featureConfig *config.FeatureConfig) error {
+	// start the appropriate controller
+	if featureConfig.CanaryConfig.IsEnabled {
+		canaryCfgMgr, err := canaryconfigmgr.MakeCanaryConfigMgr(fissionClient, kubeClient, fissionClient.GetCrdClient(),
+			featureConfig.CanaryConfig.PrometheusSvc)
+		if err != nil {
+			return fmt.Errorf("failed to start canary config manager: %v", err)
+		}
+		canaryCfgMgr.Run(context)
+		log.Printf("Started canary config manager")
+	}
+
+	return nil
+}
+
+// ConfigureFeatures gets the feature config and configures the features that are enabled
+func ConfigureFeatures(context context.Context, unitTestMode bool, fissionClient *crd.FissionClient, kubeClient *kubernetes.Clientset) (*config.FeatureConfig, error) {
+	// set feature enabled to false if unitTestMode
+	if unitTestMode {
+		featureConfig := &config.FeatureConfig{}
+		return featureConfig, nil
+	}
+
+	// get the featureConfig from config map mounted onto the file system
+	featureConfig, err := config.GetFeatureConfig()
+	if err != nil {
+		log.Printf("Error getting feature config : %v", err)
+		return featureConfig, err
+	}
+
+	// configure respective features
+	// in the future when new optional features are added, we need to add corresponding feature handlers and invoke them here
+	err = ConfigCanaryFeature(context, fissionClient, kubeClient, featureConfig)
+	return featureConfig, err
+}