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Matteo Scandoloa6a3aee2019-11-26 13:30:14 -07001/*
2 *
3 * Copyright 2017 gRPC authors.
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 */
18
19// Package status implements errors returned by gRPC. These errors are
20// serialized and transmitted on the wire between server and client, and allow
21// for additional data to be transmitted via the Details field in the status
22// proto. gRPC service handlers should return an error created by this
23// package, and gRPC clients should expect a corresponding error to be
24// returned from the RPC call.
25//
26// This package upholds the invariants that a non-nil error may not
27// contain an OK code, and an OK code must result in a nil error.
28package status
29
30import (
31 "context"
32 "errors"
33 "fmt"
34
35 "github.com/golang/protobuf/proto"
36 "github.com/golang/protobuf/ptypes"
37 spb "google.golang.org/genproto/googleapis/rpc/status"
38 "google.golang.org/grpc/codes"
39 "google.golang.org/grpc/internal"
40)
41
42func init() {
43 internal.StatusRawProto = statusRawProto
44}
45
46func statusRawProto(s *Status) *spb.Status { return s.s }
47
48// statusError is an alias of a status proto. It implements error and Status,
49// and a nil statusError should never be returned by this package.
50type statusError spb.Status
51
52func (se *statusError) Error() string {
53 p := (*spb.Status)(se)
54 return fmt.Sprintf("rpc error: code = %s desc = %s", codes.Code(p.GetCode()), p.GetMessage())
55}
56
57func (se *statusError) GRPCStatus() *Status {
58 return &Status{s: (*spb.Status)(se)}
59}
60
Arjun E K57a7fcb2020-01-30 06:44:45 +000061// Is implements future error.Is functionality.
62// A statusError is equivalent if the code and message are identical.
63func (se *statusError) Is(target error) bool {
64 tse, ok := target.(*statusError)
65 if !ok {
66 return false
67 }
68
69 return proto.Equal((*spb.Status)(se), (*spb.Status)(tse))
70}
71
Matteo Scandoloa6a3aee2019-11-26 13:30:14 -070072// Status represents an RPC status code, message, and details. It is immutable
73// and should be created with New, Newf, or FromProto.
74type Status struct {
75 s *spb.Status
76}
77
78// Code returns the status code contained in s.
79func (s *Status) Code() codes.Code {
80 if s == nil || s.s == nil {
81 return codes.OK
82 }
83 return codes.Code(s.s.Code)
84}
85
86// Message returns the message contained in s.
87func (s *Status) Message() string {
88 if s == nil || s.s == nil {
89 return ""
90 }
91 return s.s.Message
92}
93
94// Proto returns s's status as an spb.Status proto message.
95func (s *Status) Proto() *spb.Status {
96 if s == nil {
97 return nil
98 }
99 return proto.Clone(s.s).(*spb.Status)
100}
101
102// Err returns an immutable error representing s; returns nil if s.Code() is
103// OK.
104func (s *Status) Err() error {
105 if s.Code() == codes.OK {
106 return nil
107 }
108 return (*statusError)(s.s)
109}
110
111// New returns a Status representing c and msg.
112func New(c codes.Code, msg string) *Status {
113 return &Status{s: &spb.Status{Code: int32(c), Message: msg}}
114}
115
116// Newf returns New(c, fmt.Sprintf(format, a...)).
117func Newf(c codes.Code, format string, a ...interface{}) *Status {
118 return New(c, fmt.Sprintf(format, a...))
119}
120
121// Error returns an error representing c and msg. If c is OK, returns nil.
122func Error(c codes.Code, msg string) error {
123 return New(c, msg).Err()
124}
125
126// Errorf returns Error(c, fmt.Sprintf(format, a...)).
127func Errorf(c codes.Code, format string, a ...interface{}) error {
128 return Error(c, fmt.Sprintf(format, a...))
129}
130
131// ErrorProto returns an error representing s. If s.Code is OK, returns nil.
132func ErrorProto(s *spb.Status) error {
133 return FromProto(s).Err()
134}
135
136// FromProto returns a Status representing s.
137func FromProto(s *spb.Status) *Status {
138 return &Status{s: proto.Clone(s).(*spb.Status)}
139}
140
141// FromError returns a Status representing err if it was produced from this
142// package or has a method `GRPCStatus() *Status`. Otherwise, ok is false and a
143// Status is returned with codes.Unknown and the original error message.
144func FromError(err error) (s *Status, ok bool) {
145 if err == nil {
Arjun E K57a7fcb2020-01-30 06:44:45 +0000146 return nil, true
Matteo Scandoloa6a3aee2019-11-26 13:30:14 -0700147 }
148 if se, ok := err.(interface {
149 GRPCStatus() *Status
150 }); ok {
151 return se.GRPCStatus(), true
152 }
153 return New(codes.Unknown, err.Error()), false
154}
155
156// Convert is a convenience function which removes the need to handle the
157// boolean return value from FromError.
158func Convert(err error) *Status {
159 s, _ := FromError(err)
160 return s
161}
162
163// WithDetails returns a new status with the provided details messages appended to the status.
164// If any errors are encountered, it returns nil and the first error encountered.
165func (s *Status) WithDetails(details ...proto.Message) (*Status, error) {
166 if s.Code() == codes.OK {
167 return nil, errors.New("no error details for status with code OK")
168 }
169 // s.Code() != OK implies that s.Proto() != nil.
170 p := s.Proto()
171 for _, detail := range details {
172 any, err := ptypes.MarshalAny(detail)
173 if err != nil {
174 return nil, err
175 }
176 p.Details = append(p.Details, any)
177 }
178 return &Status{s: p}, nil
179}
180
181// Details returns a slice of details messages attached to the status.
182// If a detail cannot be decoded, the error is returned in place of the detail.
183func (s *Status) Details() []interface{} {
184 if s == nil || s.s == nil {
185 return nil
186 }
187 details := make([]interface{}, 0, len(s.s.Details))
188 for _, any := range s.s.Details {
189 detail := &ptypes.DynamicAny{}
190 if err := ptypes.UnmarshalAny(any, detail); err != nil {
191 details = append(details, err)
192 continue
193 }
194 details = append(details, detail.Message)
195 }
196 return details
197}
198
199// Code returns the Code of the error if it is a Status error, codes.OK if err
200// is nil, or codes.Unknown otherwise.
201func Code(err error) codes.Code {
202 // Don't use FromError to avoid allocation of OK status.
203 if err == nil {
204 return codes.OK
205 }
206 if se, ok := err.(interface {
207 GRPCStatus() *Status
208 }); ok {
209 return se.GRPCStatus().Code()
210 }
211 return codes.Unknown
212}
213
214// FromContextError converts a context error into a Status. It returns a
215// Status with codes.OK if err is nil, or a Status with codes.Unknown if err is
216// non-nil and not a context error.
217func FromContextError(err error) *Status {
218 switch err {
219 case nil:
Arjun E K57a7fcb2020-01-30 06:44:45 +0000220 return nil
Matteo Scandoloa6a3aee2019-11-26 13:30:14 -0700221 case context.DeadlineExceeded:
222 return New(codes.DeadlineExceeded, err.Error())
223 case context.Canceled:
224 return New(codes.Canceled, err.Error())
225 default:
226 return New(codes.Unknown, err.Error())
227 }
228}