Return an emulated etcd version in the status endpoint (#316)

* Return an emulated etcd version in the status endpoint
* Fix golangci-lint error
* Set default watch progress interval to 5s to ensure appropriate k8s support

Signed-off-by: Sambhav Kothari <skothari44@bloomberg.net>

main.go

@@ -98,9 +98,15 @@ func main() {
 		},
 		&cli.DurationFlag{
 			Name:        "watch-progress-notify-interval",
-			Usage:       "Interval between periodic watch progress notifications. Default is 10m.",
+			Usage:       "Interval between periodic watch progress notifications. Default is 5s to ensure support for watch progress notifications.",
 			Destination: &config.NotifyInterval,
-			Value:       time.Minute * 10,
+			Value:       time.Second * 5,
+		},
+		&cli.StringFlag{
+			Name:        "emulated-etcd-version",
+			Usage:       "The emulated etcd version to return on a call to the status endpoint. Defaults to 3.5.13, in order to indicate support for watch progress notifications.",
+			Destination: &config.EmulatedETCDVersion,
+			Value:       "3.5.13",
 		},
 		&cli.BoolFlag{Name: "debug"},
 	}

pkg/drivers/nats/new.go

@@ -224,7 +224,7 @@ func getOrCreateBucket(ctx context.Context, js jetstream.JetStream, config *Conf
 
 		// Check for temporary JetStream errors when the cluster is unhealthy and retry.
 		if jsClusterNotAvailErr.Is(err) || jsNoSuitablePeersErr.Is(err) {
-			logrus.Warnf(err.Error())
+			logrus.Warn(err.Error())
 			time.Sleep(time.Second)
 			continue
 		}

pkg/endpoint/endpoint.go

@@ -46,6 +46,7 @@ type Config struct {
 	BackendTLSConfig     tls.Config
 	MetricsRegisterer    prometheus.Registerer
 	NotifyInterval       time.Duration
+	EmulatedETCDVersion  string
 }
 
 type ETCDConfig struct {
@@ -82,7 +83,7 @@ func Listen(ctx context.Context, config Config) (ETCDConfig, error) {
 	}
 
 	// set up GRPC server and register services
-	b := server.New(backend, endpointScheme(config), config.NotifyInterval)
+	b := server.New(backend, endpointScheme(config), config.NotifyInterval, config.EmulatedETCDVersion)
 	grpcServer, err := grpcServer(config)
 	if err != nil {
 		return ETCDConfig{}, errors.Wrap(err, "creating GRPC server")

pkg/server/maintenance.go

@@ -20,8 +20,9 @@ func (s *KVServerBridge) Status(ctx context.Context, r *etcdserverpb.StatusReque
 		return nil, err
 	}
 	return &etcdserverpb.StatusResponse{
-		Header: &etcdserverpb.ResponseHeader{},
-		DbSize: size,
+		Header:  &etcdserverpb.ResponseHeader{},
+		DbSize:  size,
+		Version: s.emulatedETCDVersion,
 	}, nil
 }
 

pkg/server/server.go

@@ -11,11 +11,13 @@ import (
 )
 
 type KVServerBridge struct {
-	limited *LimitedServer
+	emulatedETCDVersion string
+	limited             *LimitedServer
 }
 
-func New(backend Backend, scheme string, notifyInterval time.Duration) *KVServerBridge {
+func New(backend Backend, scheme string, notifyInterval time.Duration, emulatedETCDVersion string) *KVServerBridge {
 	return &KVServerBridge{
+		emulatedETCDVersion: emulatedETCDVersion,
 		limited: &LimitedServer{
 			notifyInterval: notifyInterval,
 			backend:        backend,