Store 'http1' in routing table if HTTP/2 is disabled

- When routes are registered and HTTP/2 is disabled, persist the
protocol for endpoints as 'http1', even if the message has protocol
'http2'.
- It was confusing that the route registry and gorouter logs would
show protocol 'http2', even if it would really use HTTP/1.1 when
communicating with backends.
- Enabling HTTP/2 will require restarting the gorouter, so the route
registry will be regenerated with 'http2'.

[cloudfoundry/routing-release#217]
[cloudfoundry/routing-release#200]

Author: Gerg

mbus/subscriber.go

@@ -42,7 +42,7 @@ type RegistryMessage struct {
 	EndpointUpdatedAtNs     int64             `json:"endpoint_updated_at_ns"`
 }
 
-func (rm *RegistryMessage) makeEndpoint() (*route.Endpoint, error) {
+func (rm *RegistryMessage) makeEndpoint(http2Enabled bool) (*route.Endpoint, error) {
 	port, useTLS, err := rm.port()
 	if err != nil {
 		return nil, err
@@ -53,7 +53,7 @@ func (rm *RegistryMessage) makeEndpoint() (*route.Endpoint, error) {
 	}
 
 	protocol := rm.Protocol
-	if protocol == "" {
+	if protocol == "" || (!http2Enabled && protocol == "http2") {
 		protocol = "http1"
 	}
 
@@ -95,6 +95,7 @@ type Subscriber struct {
 	subscription     *nats.Subscription
 	reconnected      <-chan Signal
 	natsPendingLimit int
+	http2Enabled     bool
 
 	params startMessageParams
 
@@ -131,6 +132,7 @@ func NewSubscriber(
 		reconnected:      reconnected,
 		natsPendingLimit: c.NatsClientMessageBufferSize,
 		logger:           l,
+		http2Enabled:     c.EnableHTTP2,
 	}
 }
 
@@ -233,7 +235,7 @@ func (s *Subscriber) subscribeRoutes() (*nats.Subscription, error) {
 }
 
 func (s *Subscriber) registerEndpoint(msg *RegistryMessage) {
-	endpoint, err := msg.makeEndpoint()
+	endpoint, err := msg.makeEndpoint(s.http2Enabled)
 	if err != nil {
 		s.logger.Error("Unable to register route",
 			zap.Error(err),
@@ -248,7 +250,7 @@ func (s *Subscriber) registerEndpoint(msg *RegistryMessage) {
 }
 
 func (s *Subscriber) unregisterEndpoint(msg *RegistryMessage) {
-	endpoint, err := msg.makeEndpoint()
+	endpoint, err := msg.makeEndpoint(s.http2Enabled)
 	if err != nil {
 		s.logger.Error("Unable to unregister route",
 			zap.Error(err),

mbus/subscriber_test.go

@@ -381,7 +381,7 @@ var _ = Describe("Subscriber", func() {
 	})
 
 	Context("when the message contains a protocol", func() {
-		BeforeEach(func() {
+		JustBeforeEach(func() {
 			sub = mbus.NewSubscriber(natsClient, registry, cfg, reconnected, l)
 			process = ifrit.Invoke(sub)
 			Eventually(process.Ready()).Should(BeClosed())
@@ -410,6 +410,36 @@ var _ = Describe("Subscriber", func() {
 
 			Expect(originalEndpoint).To(Equal(expectedEndpoint))
 		})
+
+		Context("when HTTP/2 is disabled and the protocol is http2", func() {
+			BeforeEach(func() {
+				cfg.EnableHTTP2 = false
+			})
+			It("constructs the endpoint with protocol 'http1'", func() {
+				msg := mbus.RegistryMessage{
+					Host:     "host",
+					App:      "app",
+					Protocol: "http2",
+					Uris:     []route.Uri{"test.example.com"},
+				}
+
+				data, err := json.Marshal(msg)
+				Expect(err).NotTo(HaveOccurred())
+
+				err = natsClient.Publish("router.register", data)
+				Expect(err).ToNot(HaveOccurred())
+
+				Eventually(registry.RegisterCallCount).Should(Equal(1))
+				_, originalEndpoint := registry.RegisterArgsForCall(0)
+				expectedEndpoint := route.NewEndpoint(&route.EndpointOpts{
+					Host:     "host",
+					AppId:    "app",
+					Protocol: "http1",
+				})
+
+				Expect(originalEndpoint).To(Equal(expectedEndpoint))
+			})
+		})
 	})
 
 	Context("when the message contains a tls port for route", func() {