Enable Istio Sidecar injection for activator

activator.yaml

@@ -23,6 +23,8 @@ spec:
   replicas: 1
   template:
     metadata:
+      annotations:
+        sidecar.istio.io/inject: "true"
       labels:
         app: ela-activator
         role: ela-activator

elaconfig.yaml

@@ -62,13 +62,13 @@ data:
   autoscale.concurrency-quantum-of-time: "100ms"
 
   # Scale to zero feature flag
-  autoscale.enable-scale-to-zero: "false"
+  autoscale.enable-scale-to-zero: "true"
 
   # Dynamic parameters (take effect when config map is updated):
 
   # Scale to zero threshold is the time a revision must be idle before
   # it is scaled to zero.
-  autoscale.scale-to-zero-threshold: "5m"
+  autoscale.scale-to-zero-threshold: "1m"
 
 
   # LOGGING CONFIGURATION

namespace.yaml

@@ -15,4 +15,6 @@
 apiVersion: v1
 kind: Namespace
 metadata:
+  labels:
+    istio-injection: enabled
   name: ela-system

pkg/activator/activator.go

@@ -20,6 +20,7 @@ import (
 	"net/url"
 	"strings"
 	"sync"
+	"time"
 
 	"github.com/elafros/elafros/pkg/apis/ela/v1alpha1"
 	clientset "github.com/elafros/elafros/pkg/client/clientset/versioned"
@@ -92,34 +93,42 @@ func getRevisionNameFromKey(key string) (namespace string, name string, err erro
 }
 
 func (a *Activator) getRevisionTargetURL(revision *v1alpha1.Revision) (*url.URL, error) {
-	endpoint, err := a.kubeClient.CoreV1().Endpoints(revision.GetNamespace()).Get(
-		controller.GetElaK8SServiceNameForRevision(revision), metav1.GetOptions{})
+	services := a.kubeClient.CoreV1().Services(revision.GetNamespace())
+	svc, err := services.Get(controller.GetElaK8SServiceNameForRevision(revision), metav1.GetOptions{})
 	if err != nil {
 		if apierrors.IsNotFound(err) {
 			return nil, nil
 		}
 		return nil, err
 	}
-	if len(endpoint.Subsets[0].Ports) != 1 {
-		return nil, fmt.Errorf("need just one port. Found %v ports", len(endpoint.Subsets[0].Ports))
+	// TODO: in the future, the target service could have more than one ports.
+	// https://github.com/elafros/elafros/issues/837
+	if len(svc.Spec.Ports) != 1 {
+		return nil, fmt.Errorf("need just one port. Found %v ports", len(svc.Spec.Ports))
 	}
-	// TODO: figure out why do we need to use the pod IP directly to avoid the delay.
-	// We should be able to use the k8s service cluster IP.
-	// https://github.com/elafros/elafros/issues/660
-	ip := endpoint.Subsets[0].Addresses[0].IP
-	port := endpoint.Subsets[0].Ports[0].Port
 	u := &url.URL{
 		Scheme: "http",
-		Host:   fmt.Sprintf("%s:%d", ip, port),
+		Host: fmt.Sprintf("%s.%s.svc.cluster.local:%d",
+			controller.GetElaK8SServiceNameForRevision(revision), revision.Namespace, svc.Spec.Ports[0].Port),
 	}
 	return u, nil
 }
 
 func (a *Activator) proxyRequest(revRequest RevisionRequest, serviceURL *url.URL) {
-	glog.Infof("Sending a proxy request to %q", serviceURL)
+	// TODO: We need to wait a bit after the revision is marked ready.
+	// See https://github.com/elafros/elafros/issues/660: Mark a revision ready at the right time.
+	time.Sleep(2 * time.Second)
 	proxy := httputil.NewSingleHostReverseProxy(serviceURL)
 	proxy.Transport = a.tripper
+
+	// We are passing host header as a hack in tests, so the request can be matched to the right route.
+	// https://github.com/elafros/elafros/blob/2b3ee4f3c46118b3759aa95d9e6c41747c32d6c5/pkg/controller/route/ela_ingress.go#L38
+	// Since host values like "route-example.default.demo-domain.com" do not exist, we need to
+	// clear it to make istio sidecar happy if it's injected.
+	revRequest.r.Host = ""
+
 	proxy.ServeHTTP(revRequest.w, revRequest.r)
+
 	// Make sure the handler function exits after ServeHTTP function.
 	revRequest.doneCh <- struct{}{}
 	glog.Info("End proxy request")

pkg/activator/activator_test.go

@@ -173,7 +173,7 @@ func TestGetRevisionTargetURL(t *testing.T) {
 	if err != nil {
 		t.Errorf("Error in getRevisionTargetURL %v", err)
 	}
-	expectedURL := "http://abc:1234"
+	expectedURL := "http://test-rev-service.default.svc.cluster.local:1234"
 	if targetURL.String() != expectedURL {
 		t.Errorf("getRevisionTargetURL returned unexpected url %s, expected %s", targetURL, expectedURL)
 	}

sample/helloworld/helloworld.go

@@ -25,7 +25,10 @@ import (
 )
 
 func handler(w http.ResponseWriter, r *http.Request) {
-	log.Print("Hello world received a request.")
+	log.Println("Hello world received a request.")
+	log.Printf("request\n%+v", r)
+	log.Printf("request.Host\n%+v", r.Host)
+	log.Printf("request.URL.Host\n%+v", r.URL.Host)
 	target := os.Getenv("TARGET")
 	if target == "" {
 		target = "NOT SPECIFIED"