Allow to tap multiple function services at one time (#1434)

The router taps function service one by one which is inefficient and
increases the burden of executor. This PR aggregates all requests into
one to solve the problem mentioned above.

pkg/router/router_test.go

@@ -32,12 +32,12 @@ import (
 
 func TestRouter(t *testing.T) {
 	// metadata for a fake function
-	fn := &metav1.ObjectMeta{Name: "foo", Namespace: metav1.NamespaceDefault}
+	fnMeta := metav1.ObjectMeta{Name: "foo", Namespace: metav1.NamespaceDefault}
 
 	// and a reference to it
 	fr := fv1.FunctionReference{
 		Type: types.FunctionReferenceTypeFunctionName,
-		Name: fn.Name,
+		Name: fnMeta.Name,
 	}
 
 	// start a fake service
@@ -49,7 +49,7 @@ func TestRouter(t *testing.T) {
 
 	// set up the cache with this fake service
 	fmap := makeFunctionServiceMap(logger, 0)
-	fmap.assign(fn, testServiceUrl)
+	fmap.assign(&fnMeta, testServiceUrl)
 
 	// HTTP trigger set with a trigger for this function
 	triggers, _, _ := makeHTTPTriggerSet(logger, fmap, nil, nil, nil, nil,
@@ -81,12 +81,14 @@ func TestRouter(t *testing.T) {
 		triggerResourceVersion: "1234",
 	}
 
-	fnMetaMap := make(map[string]*metav1.ObjectMeta, 1)
-	fnMetaMap[fn.Name] = fn
+	fnMetaMap := make(map[string]*fv1.Function, 1)
+	fnMetaMap[fnMeta.Name] = &fv1.Function{
+		Metadata: fnMeta,
+	}
 
 	rr := resolveResult{
-		resolveResultType:   resolveResultSingleFunction,
-		functionMetadataMap: fnMetaMap,
+		resolveResultType: resolveResultSingleFunction,
+		functionMap:       fnMetaMap,
 	}
 	frr.refCache.Set(nfr, rr)