Avoid errors when req.RemoteAddr is empty

Fixes #177

Author: yugui

runtime/context.go

@@ -62,14 +62,17 @@ func AnnotateContext(ctx context.Context, req *http.Request) (context.Context, e
 	} else if req.Host != "" {
 		pairs = append(pairs, strings.ToLower(xForwardedHost), req.Host)
 	}
-	if remoteIP, _, err := net.SplitHostPort(req.RemoteAddr); err == nil {
-		if fwd := req.Header.Get(xForwardedFor); fwd == "" {
-			pairs = append(pairs, strings.ToLower(xForwardedFor), remoteIP)
+
+	if addr := req.RemoteAddr; addr != "" {
+		if remoteIP, _, err := net.SplitHostPort(addr); err == nil {
+			if fwd := req.Header.Get(xForwardedFor); fwd == "" {
+				pairs = append(pairs, strings.ToLower(xForwardedFor), remoteIP)
+			} else {
+				pairs = append(pairs, strings.ToLower(xForwardedFor), fmt.Sprintf("%s, %s", fwd, remoteIP))
+			}
 		} else {
-			pairs = append(pairs, strings.ToLower(xForwardedFor), fmt.Sprintf("%s, %s", fwd, remoteIP))
+			grpclog.Printf("invalid remote addr: %s", addr)
 		}
-	} else {
-		grpclog.Printf("invalid remote addr: %s", req.RemoteAddr)
 	}
 
 	if timeout != 0 {

runtime/context_test.go

@@ -12,7 +12,7 @@ import (
 )
 
 const (
-	emptyForwardMetaCount = 2
+	emptyForwardMetaCount = 1
 )
 
 func TestAnnotateContext_WorksWithEmpty(t *testing.T) {
@@ -22,7 +22,6 @@ func TestAnnotateContext_WorksWithEmpty(t *testing.T) {
 	if err != nil {
 		t.Fatalf("http.NewRequest(%q, %q, nil) failed with %v; want success", "GET", "http://www.example.com", err)
 	}
-	request.RemoteAddr = "192.0.2.1:12345"
 	request.Header.Add("Some-Irrelevant-Header", "some value")
 	annotated, err := runtime.AnnotateContext(ctx, request)
 	if err != nil {
@@ -31,7 +30,7 @@ func TestAnnotateContext_WorksWithEmpty(t *testing.T) {
 	}
 	md, ok := metadata.FromContext(annotated)
 	if !ok || len(md) != emptyForwardMetaCount {
-		t.Errorf("Expected 2 metadata items in context; got %v", md)
+		t.Errorf("Expected %d metadata items in context; got %v", emptyForwardMetaCount, md)
 	}
 }
 
@@ -41,7 +40,6 @@ func TestAnnotateContext_ForwardsGrpcMetadata(t *testing.T) {
 	if err != nil {
 		t.Fatalf("http.NewRequest(%q, %q, nil) failed with %v; want success", "GET", "http://www.example.com", err)
 	}
-	request.RemoteAddr = "192.168.0.1:12345"
 	request.Header.Add("Some-Irrelevant-Header", "some value")
 	request.Header.Add("Grpc-Metadata-FooBar", "Value1")
 	request.Header.Add("Grpc-Metadata-Foo-BAZ", "Value2")
@@ -54,7 +52,7 @@ func TestAnnotateContext_ForwardsGrpcMetadata(t *testing.T) {
 	}
 	md, ok := metadata.FromContext(annotated)
 	if !ok || len(md) != emptyForwardMetaCount+3 {
-		t.Errorf("Expected 5 metadata items in context; got %v", md)
+		t.Errorf("Expected %d metadata items in context; got %v", md)
 	}
 	if got, want := md["foobar"], []string{"Value1"}; !reflect.DeepEqual(got, want) {
 		t.Errorf(`md["foobar"] = %q; want %q`, got, want)
@@ -82,8 +80,8 @@ func TestAnnotateContext_XForwardedFor(t *testing.T) {
 		return
 	}
 	md, ok := metadata.FromContext(annotated)
-	if !ok || len(md) != emptyForwardMetaCount {
-		t.Errorf("Expected 2 metadata items in context; got %v", md)
+	if !ok || len(md) != emptyForwardMetaCount+1 {
+		t.Errorf("Expected %d metadata items in context; got %v", emptyForwardMetaCount+1, md)
 	}
 	if got, want := md["x-forwarded-host"], []string{"bar.foo.example.com"}; !reflect.DeepEqual(got, want) {
 		t.Errorf(`md["host"] = %v; want %v`, got, want)