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@dfawley @jadekler @jtattermusch @johanbrandhorst @ghasemloo @enocom
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/*
*
* Copyright 2017 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
// Package status implements errors returned by gRPC. These errors are
// serialized and transmitted on the wire between server and client, and allow
// for additional data to be transmitted via the Details field in the status
// proto. gRPC service handlers should return an error created by this
// package, and gRPC clients should expect a corresponding error to be
// returned from the RPC call.
//
// This package upholds the invariants that a non-nil error may not
// contain an OK code, and an OK code must result in a nil error.
package status
import (
"context"
"errors"
"fmt"
"github.com/golang/protobuf/proto"
"github.com/golang/protobuf/ptypes"
spb "google.golang.org/genproto/googleapis/rpc/status"
"google.golang.org/grpc/codes"
)
// statusError is an alias of a status proto. It implements error and Status,
// and a nil statusError should never be returned by this package.
type statusError spb.Status
func (se *statusError) Error() string {
p := (*spb.Status)(se)
return fmt.Sprintf("rpc error: code = %s desc = %s", codes.Code(p.GetCode()), p.GetMessage())
}
func (se *statusError) GRPCStatus() *Status {
return &Status{s: (*spb.Status)(se)}
}
// Status represents an RPC status code, message, and details. It is immutable
// and should be created with New, Newf, or FromProto.
type Status struct {
s *spb.Status
}
// Code returns the status code contained in s.
func (s *Status) Code() codes.Code {
if s == nil || s.s == nil {
return codes.OK
}
return codes.Code(s.s.Code)
}
// Message returns the message contained in s.
func (s *Status) Message() string {
if s == nil || s.s == nil {
return ""
}
return s.s.Message
}
// Proto returns s's status as an spb.Status proto message.
func (s *Status) Proto() *spb.Status {
if s == nil {
return nil
}
return proto.Clone(s.s).(*spb.Status)
}
// Err returns an immutable error representing s; returns nil if s.Code() is
// OK.
func (s *Status) Err() error {
if s.Code() == codes.OK {
return nil
}
return (*statusError)(s.s)
}
// New returns a Status representing c and msg.
func New(c codes.Code, msg string) *Status {
return &Status{s: &spb.Status{Code: int32(c), Message: msg}}
}
// Newf returns New(c, fmt.Sprintf(format, a...)).
func Newf(c codes.Code, format string, a ...interface{}) *Status {
return New(c, fmt.Sprintf(format, a...))
}
// Error returns an error representing c and msg. If c is OK, returns nil.
func Error(c codes.Code, msg string) error {
return New(c, msg).Err()
}
// Errorf returns Error(c, fmt.Sprintf(format, a...)).
func Errorf(c codes.Code, format string, a ...interface{}) error {
return Error(c, fmt.Sprintf(format, a...))
}
// ErrorProto returns an error representing s. If s.Code is OK, returns nil.
func ErrorProto(s *spb.Status) error {
return FromProto(s).Err()
}
// FromProto returns a Status representing s.
func FromProto(s *spb.Status) *Status {
return &Status{s: proto.Clone(s).(*spb.Status)}
}
// FromError returns a Status representing err if it was produced from this
// package or has a method `GRPCStatus() *Status`. Otherwise, ok is false and a
// Status is returned with codes.Unknown and the original error message.
func FromError(err error) (s *Status, ok bool) {
if err == nil {
return &Status{s: &spb.Status{Code: int32(codes.OK)}}, true
}
if se, ok := err.(interface {
GRPCStatus() *Status
}); ok {
return se.GRPCStatus(), true
}
return New(codes.Unknown, err.Error()), false
}
// Convert is a convenience function which removes the need to handle the
// boolean return value from FromError.
func Convert(err error) *Status {
s, _ := FromError(err)
return s
}
// WithDetails returns a new status with the provided details messages appended to the status.
// If any errors are encountered, it returns nil and the first error encountered.
func (s *Status) WithDetails(details ...proto.Message) (*Status, error) {
if s.Code() == codes.OK {
return nil, errors.New("no error details for status with code OK")
}
// s.Code() != OK implies that s.Proto() != nil.
p := s.Proto()
for _, detail := range details {
any, err := ptypes.MarshalAny(detail)
if err != nil {
return nil, err
}
p.Details = append(p.Details, any)
}
return &Status{s: p}, nil
}
// Details returns a slice of details messages attached to the status.
// If a detail cannot be decoded, the error is returned in place of the detail.
func (s *Status) Details() []interface{} {
if s == nil || s.s == nil {
return nil
}
details := make([]interface{}, 0, len(s.s.Details))
for _, any := range s.s.Details {
detail := &ptypes.DynamicAny{}
if err := ptypes.UnmarshalAny(any, detail); err != nil {
details = append(details, err)
continue
}
details = append(details, detail.Message)
}
return details
}
// Code returns the Code of the error if it is a Status error, codes.OK if err
// is nil, or codes.Unknown otherwise.
func Code(err error) codes.Code {
// Don't use FromError to avoid allocation of OK status.
if err == nil {
return codes.OK
}
if se, ok := err.(interface {
GRPCStatus() *Status
}); ok {
return se.GRPCStatus().Code()
}
return codes.Unknown
}
// FromContextError converts a context error into a Status. It returns a
// Status with codes.OK if err is nil, or a Status with codes.Unknown if err is
// non-nil and not a context error.
func FromContextError(err error) *Status {
switch err {
case nil:
return New(codes.OK, "")
case context.DeadlineExceeded:
return New(codes.DeadlineExceeded, err.Error())
case context.Canceled:
return New(codes.Canceled, err.Error())
default:
return New(codes.Unknown, err.Error())
}
}
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