https://github.com/grpc-ecosystem/grpc-gateway/blob/master/runtime/errors.go#L15
package runtime
import (
"context"
"io"
"net/http"
"github.com/golang/protobuf/proto"
"github.com/golang/protobuf/ptypes/any"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/grpclog"
"google.golang.org/grpc/status"
)
// HTTPStatusFromCode converts a gRPC error code into the corresponding HTTP response status.
// See: https://github.com/googleapis/googleapis/blob/master/google/rpc/code.proto
func HTTPStatusFromCode(code codes.Code) int {
switch code {
case codes.OK:
return http.StatusOK
case codes.Canceled:
return http.StatusRequestTimeout
case codes.Unknown:
return http.StatusInternalServerError
case codes.InvalidArgument:
return http.StatusBadRequest
case codes.DeadlineExceeded:
return http.StatusGatewayTimeout
case codes.NotFound:
return http.StatusNotFound
case codes.AlreadyExists:
return http.StatusConflict
case codes.PermissionDenied:
return http.StatusForbidden
case codes.Unauthenticated:
return http.StatusUnauthorized
case codes.ResourceExhausted:
return http.StatusTooManyRequests
case codes.FailedPrecondition:
return http.StatusPreconditionFailed
case codes.Aborted:
return http.StatusConflict
case codes.OutOfRange:
return http.StatusBadRequest
case codes.Unimplemented:
return http.StatusNotImplemented
case codes.Internal:
return http.StatusInternalServerError
case codes.Unavailable:
return http.StatusServiceUnavailable
case codes.DataLoss:
return http.StatusInternalServerError
}
grpclog.Infof("Unknown gRPC error code: %v", code)
return http.StatusInternalServerError
}
var (
// HTTPError replies to the request with the error.
// You can set a custom function to this variable to customize error format.
HTTPError = DefaultHTTPError
// OtherErrorHandler handles the following error used by the gateway: StatusMethodNotAllowed StatusNotFound and StatusBadRequest
OtherErrorHandler = DefaultOtherErrorHandler
)
type errorBody struct {
Error string `protobuf:"bytes,1,name=error" json:"error"`
// This is to make the error more compatible with users that expect errors to be Status objects:
// https://github.com/grpc/grpc/blob/master/src/proto/grpc/status/status.proto
// It should be the exact same message as the Error field.
Message string `protobuf:"bytes,1,name=message" json:"message"`
Code int32 `protobuf:"varint,2,name=code" json:"code"`
Details []*any.Any `protobuf:"bytes,3,rep,name=details" json:"details,omitempty"`
}
// Make this also conform to proto.Message for builtin JSONPb Marshaler
func (e *errorBody) Reset() { *e = errorBody{} }
func (e *errorBody) String() string { return proto.CompactTextString(e) }
func (*errorBody) ProtoMessage() {}
// DefaultHTTPError is the default implementation of HTTPError.
// If "err" is an error from gRPC system, the function replies with the status code mapped by HTTPStatusFromCode.
// If otherwise, it replies with http.StatusInternalServerError.
//
// The response body returned by this function is a JSON object,
// which contains a member whose key is "error" and whose value is err.Error().
func DefaultHTTPError(ctx context.Context, mux *ServeMux, marshaler Marshaler, w http.ResponseWriter, _ *http.Request, err error) {
const fallback = `{"error": "failed to marshal error message"}`
w.Header().Del("Trailer")
w.Header().Set("Content-Type", marshaler.ContentType())
s, ok := status.FromError(err)
if !ok {
s = status.New(codes.Unknown, err.Error())
}
body := &errorBody{
Error: s.Message(),
Message: s.Message(),
Code: int32(s.Code()),
Details: s.Proto().GetDetails(),
}
buf, merr := marshaler.Marshal(body)
if merr != nil {
grpclog.Infof("Failed to marshal error message %q: %v", body, merr)
w.WriteHeader(http.StatusInternalServerError)
if _, err := io.WriteString(w, fallback); err != nil {
grpclog.Infof("Failed to write response: %v", err)
}
return
}
md, ok := ServerMetadataFromContext(ctx)
if !ok {
grpclog.Infof("Failed to extract ServerMetadata from context")
}
handleForwardResponseServerMetadata(w, mux, md)
handleForwardResponseTrailerHeader(w, md)
st := HTTPStatusFromCode(s.Code())
w.WriteHeader(st)
if _, err := w.Write(buf); err != nil {
grpclog.Infof("Failed to write response: %v", err)
}
handleForwardResponseTrailer(w, md)
}
// DefaultOtherErrorHandler is the default implementation of OtherErrorHandler.
// It simply writes a string representation of the given error into "w".
func DefaultOtherErrorHandler(w http.ResponseWriter, _ *http.Request, msg string, code int) {
http.Error(w, msg, code)
}
https://github.com/googleapis/googleapis/blob/master/google/rpc/code.proto
// Copyright 2017 Google Inc.
//
// 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.
syntax = "proto3";
package google.rpc;
option go_package = "google.golang.org/genproto/googleapis/rpc/code;code";
option java_multiple_files = true;
option java_outer_classname = "CodeProto";
option java_package = "com.google.rpc";
option objc_class_prefix = "RPC";
// The canonical error codes for Google APIs.
//
//
// Sometimes multiple error codes may apply. Services should return
// the most specific error code that applies. For example, prefer
// `OUT_OF_RANGE` over `FAILED_PRECONDITION` if both codes apply.
// Similarly prefer `NOT_FOUND` or `ALREADY_EXISTS` over `FAILED_PRECONDITION`.
enum Code {
// Not an error; returned on success
//
// HTTP Mapping: 200 OK
OK = 0;
// The operation was cancelled, typically by the caller.
//
// HTTP Mapping: 499 Client Closed Request
CANCELLED = 1;
// Unknown error. For example, this error may be returned when
// a `Status` value received from another address space belongs to
// an error space that is not known in this address space. Also
// errors raised by APIs that do not return enough error information
// may be converted to this error.
//
// HTTP Mapping: 500 Internal Server Error
UNKNOWN = 2;
// The client specified an invalid argument. Note that this differs
// from `FAILED_PRECONDITION`. `INVALID_ARGUMENT` indicates arguments
// that are problematic regardless of the state of the system
// (e.g., a malformed file name).
//
// HTTP Mapping: 400 Bad Request
INVALID_ARGUMENT = 3;
// The deadline expired before the operation could complete. For operations
// that change the state of the system, this error may be returned
// even if the operation has completed successfully. For example, a
// successful response from a server could have been delayed long
// enough for the deadline to expire.
//
// HTTP Mapping: 504 Gateway Timeout
DEADLINE_EXCEEDED = 4;
// Some requested entity (e.g., file or directory) was not found.
//
// Note to server developers: if a request is denied for an entire class
// of users, such as gradual feature rollout or undocumented whitelist,
// `NOT_FOUND` may be used. If a request is denied for some users within
// a class of users, such as user-based access control, `PERMISSION_DENIED`
// must be used.
//
// HTTP Mapping: 404 Not Found
NOT_FOUND = 5;
// The entity that a client attempted to create (e.g., file or directory)
// already exists.
//
// HTTP Mapping: 409 Conflict
ALREADY_EXISTS = 6;
// The caller does not have permission to execute the specified
// operation. `PERMISSION_DENIED` must not be used for rejections
// caused by exhausting some resource (use `RESOURCE_EXHAUSTED`
// instead for those errors). `PERMISSION_DENIED` must not be
// used if the caller can not be identified (use `UNAUTHENTICATED`
// instead for those errors). This error code does not imply the
// request is valid or the requested entity exists or satisfies
// other pre-conditions.
//
// HTTP Mapping: 403 Forbidden
PERMISSION_DENIED = 7;
// The request does not have valid authentication credentials for the
// operation.
//
// HTTP Mapping: 401 Unauthorized
UNAUTHENTICATED = 16;
// Some resource has been exhausted, perhaps a per-user quota, or
// perhaps the entire file system is out of space.
//
// HTTP Mapping: 429 Too Many Requests
RESOURCE_EXHAUSTED = 8;
// The operation was rejected because the system is not in a state
// required for the operation's execution. For example, the directory
// to be deleted is non-empty, an rmdir operation is applied to
// a non-directory, etc.
//
// Service implementors can use the following guidelines to decide
// between `FAILED_PRECONDITION`, `ABORTED`, and `UNAVAILABLE`:
// (a) Use `UNAVAILABLE` if the client can retry just the failing call.
// (b) Use `ABORTED` if the client should retry at a higher level
// (e.g., when a client-specified test-and-set fails, indicating the
// client should restart a read-modify-write sequence).
// (c) Use `FAILED_PRECONDITION` if the client should not retry until
// the system state has been explicitly fixed. E.g., if an "rmdir"
// fails because the directory is non-empty, `FAILED_PRECONDITION`
// should be returned since the client should not retry unless
// the files are deleted from the directory.
//
// HTTP Mapping: 400 Bad Request
FAILED_PRECONDITION = 9;
// The operation was aborted, typically due to a concurrency issue such as
// a sequencer check failure or transaction abort.
//
// See the guidelines above for deciding between `FAILED_PRECONDITION`,
// `ABORTED`, and `UNAVAILABLE`.
//
// HTTP Mapping: 409 Conflict
ABORTED = 10;
// The operation was attempted past the valid range. E.g., seeking or
// reading past end-of-file.
//
// Unlike `INVALID_ARGUMENT`, this error indicates a problem that may
// be fixed if the system state changes. For example, a 32-bit file
// system will generate `INVALID_ARGUMENT` if asked to read at an
// offset that is not in the range [0,2^32-1], but it will generate
// `OUT_OF_RANGE` if asked to read from an offset past the current
// file size.
//
// There is a fair bit of overlap between `FAILED_PRECONDITION` and
// `OUT_OF_RANGE`. We recommend using `OUT_OF_RANGE` (the more specific
// error) when it applies so that callers who are iterating through
// a space can easily look for an `OUT_OF_RANGE` error to detect when
// they are done.
//
// HTTP Mapping: 400 Bad Request
OUT_OF_RANGE = 11;
// The operation is not implemented or is not supported/enabled in this
// service.
//
// HTTP Mapping: 501 Not Implemented
UNIMPLEMENTED = 12;
// Internal errors. This means that some invariants expected by the
// underlying system have been broken. This error code is reserved
// for serious errors.
//
// HTTP Mapping: 500 Internal Server Error
INTERNAL = 13;
// The service is currently unavailable. This is most likely a
// transient condition, which can be corrected by retrying with
// a backoff.
//
// See the guidelines above for deciding between `FAILED_PRECONDITION`,
// `ABORTED`, and `UNAVAILABLE`.
//
// HTTP Mapping: 503 Service Unavailable
UNAVAILABLE = 14;
// Unrecoverable data loss or corruption.
//
// HTTP Mapping: 500 Internal Server Error
DATA_LOSS = 15;
}
grpc-ecosystem/grpc-gateway: gRPC to JSON proxy generator following the gRPC HTTP spec
https://github.com/grpc-ecosystem/grpc-gateway
