Log current available routes on error (#388)

google_guest_agent/accounts_windows.go

@@ -111,7 +111,7 @@ func resetPwd(username, pwd string) error {
 	return nil
 }
 
-func addUserToGroup(ctx context.Context, username, group string) error {
+func addUserToGroup(_ context.Context, username, group string) error {
 	gPtr, err := syscall.UTF16PtrFromString(group)
 	if err != nil {
 		return fmt.Errorf("error encoding group to UTF16: %v", err)
@@ -138,7 +138,7 @@ func addUserToGroup(ctx context.Context, username, group string) error {
 	return nil
 }
 
-func createUser(ctx context.Context, username, pwd, _ string) error {
+func createUser(_ context.Context, username, pwd, _ string) error {
 	uPtr, err := syscall.UTF16PtrFromString(username)
 	if err != nil {
 		return fmt.Errorf("error encoding username to UTF16: %v", err)
@@ -189,6 +189,6 @@ func userExists(name string) (bool, error) {
 	return true, nil
 }
 
-func getUIDAndGID(path string) (string, string) {
+func getUIDAndGID(_ string) (string, string) {
 	return "", ""
 }

google_guest_agent/instance_setup.go

@@ -37,13 +37,15 @@ import (
 func getDefaultAdapter(fes []ipForwardEntry) (*ipForwardEntry, error) {
 	// Choose the first adapter index that has the default route setup.
 	// This is equivalent to how route.exe works when interface is not provided.
+	defaultRoute := net.ParseIP("0.0.0.0")
 	sort.Slice(fes, func(i, j int) bool { return fes[i].ipForwardIfIndex < fes[j].ipForwardIfIndex })
 	for _, fe := range fes {
-		if fe.ipForwardDest.Equal(net.ParseIP("0.0.0.0")) {
+		if fe.ipForwardDest.Equal(defaultRoute) {
 			return &fe, nil
 		}
 	}
-	return nil, fmt.Errorf("could not find default route")
+
+	return nil, fmt.Errorf("no default route to %s found in %+v forward entries", defaultRoute.String(), fes)
 }
 
 func addMetadataRoute() error {