util/errors: add ErrForbidden

internal/services/gateway/api/api.go

@@ -34,6 +34,8 @@ func ErrorResponseFromError(err error) *ErrorResponse {
 	case util.IsErrBadRequest(err):
 		fallthrough
 	case util.IsErrNotFound(err):
+		fallthrough
+	case util.IsErrForbidden(err):
 		return &ErrorResponse{Message: err.Error()}
 	}
 
@@ -59,6 +61,9 @@ func httpError(w http.ResponseWriter, err error) bool {
 	case util.IsErrNotFound(err):
 		w.WriteHeader(http.StatusNotFound)
 		w.Write(resj)
+	case util.IsErrForbidden(err):
+		w.WriteHeader(http.StatusForbidden)
+		w.Write(resj)
 	default:
 		w.WriteHeader(http.StatusInternalServerError)
 		w.Write(resj)

internal/util/errors.go

@@ -93,3 +93,22 @@ func IsErrNotFound(err error) bool {
 	_, ok := err.(*ErrNotFound)
 	return ok
 }
+
+// ErrForbidden represent an error caused by an forbidden operation
+// it's used to differentiate an internal error from an user error
+type ErrForbidden struct {
+	Err error
+}
+
+func (e *ErrForbidden) Error() string {
+	return e.Err.Error()
+}
+
+func NewErrForbidden(err error) *ErrForbidden {
+	return &ErrForbidden{Err: err}
+}
+
+func IsErrForbidden(err error) bool {
+	_, ok := err.(*ErrForbidden)
+	return ok
+}