Put existing work for an experimental backpressure feature under a feature flag

charts/osm/templates/osm-deployment.yaml

@@ -42,6 +42,9 @@ spec:
             {{- if .Values.OpenServiceMesh.enableDebugServer }}
             "--enableDebugServer",
             {{- end }}
+            {{- if .Values.OpenServiceMesh.enableBackpressureExperimental }}
+            "--enable-backpressure-experimental",
+            {{- end }}
           ]
           resources:
             limits:

charts/osm/values.yaml

@@ -27,4 +27,5 @@ OpenServiceMesh:
     port: 9411
   enableDebugServer: false
   enablePermissiveTrafficPolicy: false
+  enableBackpressureExperimental: false
   meshName: osm

cmd/ads/ads.go

@@ -96,6 +96,9 @@ func init() {
 	flags.IntVar(&injectorConfig.ListenPort, "webhook-port", constants.InjectorWebhookPort, "Webhook port for sidecar-injector")
 	flags.StringVar(&injectorConfig.InitContainerImage, "init-container-image", "", "InitContainer image")
 	flags.StringVar(&injectorConfig.SidecarImage, "sidecar-image", "", "Sidecar proxy Container image")
+
+	// feature flags
+	flags.BoolVar(&optionalFeatures.Backpressure, "enable-backpressure-experimental", false, "Enable experimental backpressure feature")
 }
 
 func main() {

cmd/cli/install.go

@@ -61,21 +61,22 @@ const (
 var chartTGZSource string
 
 type installCmd struct {
-	out                           io.Writer
-	containerRegistry             string
-	containerRegistrySecret       string
-	chartPath                     string
-	osmImageTag                   string
-	certManager                   string
-	vaultHost                     string
-	vaultProtocol                 string
-	vaultToken                    string
-	vaultRole                     string
-	serviceCertValidityMinutes    int
-	prometheusRetentionTime       string
-	enableDebugServer             bool
-	enablePermissiveTrafficPolicy bool
-	meshName                      string
+	out                            io.Writer
+	containerRegistry              string
+	containerRegistrySecret        string
+	chartPath                      string
+	osmImageTag                    string
+	certManager                    string
+	vaultHost                      string
+	vaultProtocol                  string
+	vaultToken                     string
+	vaultRole                      string
+	serviceCertValidityMinutes     int
+	prometheusRetentionTime        string
+	enableDebugServer              bool
+	enablePermissiveTrafficPolicy  bool
+	enableBackpressureExperimental bool
+	meshName                       string
 
 	// checker runs checks before any installation is attempted. Its type is
 	// abstract here to make testing easy.
@@ -113,6 +114,7 @@ func newInstallCmd(config *helm.Configuration, out io.Writer) *cobra.Command {
 	f.StringVar(&inst.prometheusRetentionTime, "prometheus-retention-time", constants.PrometheusDefaultRetentionTime, "Duration for which data will be retained in prometheus")
 	f.BoolVar(&inst.enableDebugServer, "enable-debug-server", false, "Enable the debug HTTP server")
 	f.BoolVar(&inst.enablePermissiveTrafficPolicy, "enable-permissive-traffic-policy", false, "Enable permissive traffic policy mode")
+	f.BoolVar(&inst.enableBackpressureExperimental, "enable-backpressure-experimental", false, "Enable experimental backpressure feature")
 	f.StringVar(&inst.meshName, "mesh-name", defaultMeshName, "Name of the service mesh")
 
 	return cmd
@@ -206,6 +208,7 @@ func (i *installCmd) resolveValues() (map[string]interface{}, error) {
 		fmt.Sprintf("OpenServiceMesh.prometheus.retention.time=%s", i.prometheusRetentionTime),
 		fmt.Sprintf("OpenServiceMesh.enableDebugServer=%t", i.enableDebugServer),
 		fmt.Sprintf("OpenServiceMesh.enablePermissiveTrafficPolicy=%t", i.enablePermissiveTrafficPolicy),
+		fmt.Sprintf("OpenServiceMesh.enableBackpressureExperimental=%t", i.enableBackpressureExperimental),
 		fmt.Sprintf("OpenServiceMesh.meshName=%s", i.meshName),
 	}
 

cmd/cli/install_test.go

@@ -128,8 +128,9 @@ var _ = Describe("Running the install command", func() {
 							"retention": map[string]interface{}{
 								"time": "5d",
 							}},
-						"enableDebugServer":             false,
-						"enablePermissiveTrafficPolicy": false,
+						"enableDebugServer":              false,
+						"enablePermissiveTrafficPolicy":  false,
+						"enableBackpressureExperimental": false,
 					}}))
 			})
 
@@ -225,8 +226,9 @@ var _ = Describe("Running the install command", func() {
 							"retention": map[string]interface{}{
 								"time": "5d",
 							}},
-						"enableDebugServer":             false,
-						"enablePermissiveTrafficPolicy": false,
+						"enableDebugServer":              false,
+						"enablePermissiveTrafficPolicy":  false,
+						"enableBackpressureExperimental": false,
 					}}))
 			})
 
@@ -327,8 +329,9 @@ var _ = Describe("Running the install command", func() {
 								"time": "5d",
 							},
 						},
-						"enableDebugServer":             false,
-						"enablePermissiveTrafficPolicy": false,
+						"enableDebugServer":              false,
+						"enablePermissiveTrafficPolicy":  false,
+						"enableBackpressureExperimental": false,
 					}}))
 			})
 
@@ -586,8 +589,9 @@ var _ = Describe("Resolving values for install command with vault parameters", f
 						"time": "5d",
 					},
 				},
-				"enableDebugServer":             false,
-				"enablePermissiveTrafficPolicy": false,
+				"enableDebugServer":              false,
+				"enablePermissiveTrafficPolicy":  false,
+				"enableBackpressureExperimental": false,
 			}}))
 	})
 })

go.sum

@@ -914,6 +914,8 @@ k8s.io/cli-runtime v0.18.0/go.mod h1:1eXfmBsIJosjn9LjEBUd2WVPoPAY9XGTqTFcPMIBsUQ
 k8s.io/client-go v0.17.4/go.mod h1:ouF6o5pz3is8qU0/qYL2RnoxOPqgfuidYLowytyLJmc=
 k8s.io/client-go v0.18.0 h1:yqKw4cTUQraZK3fcVCMeSa+lqKwcjZ5wtcOIPnxQno4=
 k8s.io/client-go v0.18.0/go.mod h1:uQSYDYs4WhVZ9i6AIoEZuwUggLVEF64HOD37boKAtF8=
+k8s.io/client-go v1.5.1 h1:XaX/lo2/u3/pmFau8HN+sB5C/b4dc4Dmm2eXjBH4p1E=
+k8s.io/client-go v11.0.0+incompatible h1:LBbX2+lOwY9flffWlJM7f1Ct8V2SRNiMRDFeiwnJo9o=
 k8s.io/code-generator v0.17.4/go.mod h1:l8BLVwASXQZTo2xamW5mQNFCe1XPiAesVq7Y1t7PiQQ=
 k8s.io/code-generator v0.18.0/go.mod h1:+UHX5rSbxmR8kzS+FAv7um6dtYrZokQvjHpDSYRVkTc=
 k8s.io/code-generator v0.18.3 h1:5H57pYEbkMMXCLKD16YQH3yDPAbVLweUsB1M3m70D1c=

pkg/featureflags/featureflags.go

@@ -9,6 +9,7 @@ import (
 // OptionalFeatures is a struct to enable/disable optional features
 type OptionalFeatures struct {
 	// FeatureName bool
+	Backpressure bool
 }
 
 var (
@@ -32,3 +33,8 @@ func IsFeatureNameEnabled() bool {
 	return Features.FeatureName
 }
 */
+
+// IsBackpressureEnabled returns a boolean indicating if the experimental backpressure feature is enabled
+func IsBackpressureEnabled() bool {
+	return Features.Backpressure
+}

pkg/smi/client.go

@@ -22,6 +22,7 @@ import (
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/cache"
 
+	"github.com/open-service-mesh/osm/pkg/featureflags"
 	k8s "github.com/open-service-mesh/osm/pkg/kubernetes"
 	"github.com/open-service-mesh/osm/pkg/namespace"
 	"github.com/open-service-mesh/osm/pkg/service"
@@ -35,7 +36,10 @@ func NewMeshSpecClient(smiKubeConfig *rest.Config, kubeClient kubernetes.Interfa
 	smiTrafficSplitClientSet := smiTrafficSplitClient.NewForConfigOrDie(smiKubeConfig)
 	smiTrafficSpecClientSet := smiTrafficSpecClient.NewForConfigOrDie(smiKubeConfig)
 	smiTrafficTargetClientSet := smiTrafficTargetClient.NewForConfigOrDie(smiKubeConfig)
-	backpressureClientSet := backpressureClient.NewForConfigOrDie(smiKubeConfig)
+	var backpressureClientSet *backpressureClient.Clientset
+	if featureflags.IsBackpressureEnabled() {
+		backpressureClientSet = backpressureClient.NewForConfigOrDie(smiKubeConfig)
+	}
 
 	client := newSMIClient(kubeClient, smiTrafficSplitClientSet, smiTrafficSpecClientSet, smiTrafficTargetClientSet, backpressureClientSet, osmNamespace, namespaceController, kubernetesClientName)
 
@@ -111,15 +115,18 @@ func newSMIClient(kubeClient kubernetes.Interface, smiTrafficSplitClient *smiTra
 		TrafficSplit:  smiTrafficSplitInformerFactory.Split().V1alpha2().TrafficSplits().Informer(),
 		TrafficSpec:   smiTrafficSpecInformerFactory.Specs().V1alpha2().HTTPRouteGroups().Informer(),
 		TrafficTarget: smiTrafficTargetInformerFactory.Access().V1alpha1().TrafficTargets().Informer(),
-		Backpressure:  backPressureInformerFactory.Policy().V1alpha1().Backpressures().Informer(),
 	}
 
 	cacheCollection := CacheCollection{
 		Services:      informerCollection.Services.GetStore(),
 		TrafficSplit:  informerCollection.TrafficSplit.GetStore(),
 		TrafficSpec:   informerCollection.TrafficSpec.GetStore(),
 		TrafficTarget: informerCollection.TrafficTarget.GetStore(),
-		Backpressure:  informerCollection.Backpressure.GetStore(),
+	}
+
+	if featureflags.IsBackpressureEnabled() {
+		informerCollection.Backpressure = backPressureInformerFactory.Policy().V1alpha1().Backpressures().Informer()
+		cacheCollection.Backpressure = informerCollection.Backpressure.GetStore()
 	}
 
 	client := Client{
@@ -140,7 +147,9 @@ func newSMIClient(kubeClient kubernetes.Interface, smiTrafficSplitClient *smiTra
 	informerCollection.TrafficSplit.AddEventHandler(k8s.GetKubernetesEventHandlers("TrafficSplit", "SMI", client.announcements, shouldObserve))
 	informerCollection.TrafficSpec.AddEventHandler(k8s.GetKubernetesEventHandlers("TrafficSpec", "SMI", client.announcements, shouldObserve))
 	informerCollection.TrafficTarget.AddEventHandler(k8s.GetKubernetesEventHandlers("TrafficTarget", "SMI", client.announcements, shouldObserve))
-	informerCollection.Backpressure.AddEventHandler(k8s.GetKubernetesEventHandlers("Backpressure", "SMI", client.announcements, shouldObserve))
+	if featureflags.IsBackpressureEnabled() {
+		informerCollection.Backpressure.AddEventHandler(k8s.GetKubernetesEventHandlers("Backpressure", "SMI", client.announcements, shouldObserve))
+	}
 
 	return &client
 }
@@ -199,6 +208,12 @@ func (c *Client) ListTrafficTargets() []*target.TrafficTarget {
 // ListBackpressures implements smi.MeshSpec by returning the list of backpressures
 func (c *Client) ListBackpressures() []*backpressure.Backpressure {
 	var backpressureList []*backpressure.Backpressure
+
+	if !featureflags.IsBackpressureEnabled() {
+		log.Info().Msgf("Backpressure turned off!")
+		return nil
+	}
+
 	for _, pressureIface := range c.caches.Backpressure.List() {
 		backpressure := pressureIface.(*backpressure.Backpressure)
 		// TODO: Add type assertion check using renamed variable when merging with main