vendor/cloud.google.com/go/internal/annotate.go

   1 // Copyright 2017 Google LLC
   2 //
   3 // Licensed under the Apache License, Version 2.0 (the "License");
   4 // you may not use this file except in compliance with the License.
   5 // You may obtain a copy of the License at
   6 //
   7 //      http://www.apache.org/licenses/LICENSE-2.0
   8 //
   9 // Unless required by applicable law or agreed to in writing, software
  10 // distributed under the License is distributed on an "AS IS" BASIS,
  11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12 // See the License for the specific language governing permissions and
  13 // limitations under the License.
  14
  15 package internal
  16
  17 import (
  18         "fmt"
  19
  20         "google.golang.org/api/googleapi"
  21         "google.golang.org/grpc/status"
  22 )
  23
  24 // Annotate prepends msg to the error message in err, attempting
  25 // to preserve other information in err, like an error code.
  26 //
  27 // Annotate panics if err is nil.
  28 //
  29 // Annotate knows about these error types:
  30 // - "google.golang.org/grpc/status".Status
  31 // - "google.golang.org/api/googleapi".Error
  32 // If the error is not one of these types, Annotate behaves
  33 // like
  34 //   fmt.Errorf("%s: %v", msg, err)
  35 func Annotate(err error, msg string) error {
  36         if err == nil {
  37                 panic("Annotate called with nil")
  38         }
  39         if s, ok := status.FromError(err); ok {
  40                 p := s.Proto()
  41                 p.Message = msg + ": " + p.Message
  42                 return status.ErrorProto(p)
  43         }
  44         if g, ok := err.(*googleapi.Error); ok {
  45                 g.Message = msg + ": " + g.Message
  46                 return g
  47         }
  48         return fmt.Errorf("%s: %v", msg, err)
  49 }
  50
  51 // Annotatef uses format and args to format a string, then calls Annotate.
  52 func Annotatef(err error, format string, args ...interface{}) error {
  53         return Annotate(err, fmt.Sprintf(format, args...))
  54 }