Support function resolution in multiple namespaces

**What**
- Ensure that the pass only the function name to the Endpoint lister,
  because the namespace is already set when constructing the lister.
  The existing code would always return a 404 because it sent the
  "function_name.namespace" as the function name. This can never be
  found since it is not a valid service name
- Update the error messages to make the component parts of the message
  easier to read.  It will now be easier to see which part is the error
  from the k8s api.

Signed-off-by: Lucas Roesler <roesler.lucas@gmail.com>

pkg/k8s/proxy.go

@@ -55,12 +55,16 @@ func getNamespace(name, defaultNamespace string) string {
 }
 
 func (l *FunctionLookup) Resolve(name string) (url.URL, error) {
-
+	functionName := name
 	namespace := getNamespace(name, l.DefaultNamespace)
 	if err := l.verifyNamespace(namespace); err != nil {
 		return url.URL{}, err
 	}
 
+	if strings.Contains(name, ".") {
+		functionName = strings.TrimSuffix(name, "."+namespace)
+	}
+
 	nsEndpointLister := l.GetLister(namespace)
 
 	if nsEndpointLister == nil {
@@ -69,18 +73,18 @@ func (l *FunctionLookup) Resolve(name string) (url.URL, error) {
 		nsEndpointLister = l.GetLister(namespace)
 	}
 
-	svc, err := nsEndpointLister.Get(name)
+	svc, err := nsEndpointLister.Get(functionName)
 	if err != nil {
-		return url.URL{}, fmt.Errorf("error listing %s.%s %s", name, namespace, err.Error())
+		return url.URL{}, fmt.Errorf("error listing \"%s.%s\": %s", functionName, namespace, err.Error())
 	}
 
 	if len(svc.Subsets) == 0 {
-		return url.URL{}, fmt.Errorf("no subsets available for %s.%s", name, namespace)
+		return url.URL{}, fmt.Errorf("no subsets available for \"%s.%s\"", functionName, namespace)
 	}
 
 	all := len(svc.Subsets[0].Addresses)
 	if len(svc.Subsets[0].Addresses) == 0 {
-		return url.URL{}, fmt.Errorf("no addresses in subset for %s.%s", name, namespace)
+		return url.URL{}, fmt.Errorf("no addresses in subset for \"%s.%s\"", functionName, namespace)
 	}
 
 	target := rand.Intn(all)

pkg/k8s/proxy_test.go

@@ -1,6 +1,7 @@
 package k8s
 
 import (
+	"fmt"
 	"strings"
 	"testing"
 
@@ -30,14 +31,16 @@ func (f FakeNSLister) List(selector labels.Selector) (ret []*corev1.Endpoints, e
 }
 
 func (f FakeNSLister) Get(name string) (*corev1.Endpoints, error) {
+
+	// make sure that we only send the function name to the lister
+	if strings.Contains(name, ".") {
+		return nil, fmt.Errorf("can not look up function name with a dot!")
+	}
+
 	ep := corev1.Endpoints{
-		Subsets: []corev1.EndpointSubset{
-			corev1.EndpointSubset{
-				Addresses: []corev1.EndpointAddress{
-					corev1.EndpointAddress{IP: "127.0.0.1"},
-				},
-			},
-		},
+		Subsets: []corev1.EndpointSubset{{
+			Addresses: []corev1.EndpointAddress{{IP: "127.0.0.1"}},
+		}},
 	}
 
 	return &ep, nil