prometheus/vendor/github.com/grpc-ecosystem/grpc-gateway/runtime/errors.go
2017-07-06 14:38:20 +02:00

122 lines
3.8 KiB
Go

package runtime
import (
"io"
"net/http"
"github.com/golang/protobuf/proto"
"golang.org/x/net/context"
"google.golang.org/grpc"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/grpclog"
)
// HTTPStatusFromCode converts a gRPC error code into the corresponding HTTP response status.
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.StatusRequestTimeout
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.StatusForbidden
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.Printf("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"`
Code int32 `protobuf:"varint,2,name=code" json:"code"`
}
//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, 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())
body := &errorBody{
Error: grpc.ErrorDesc(err),
Code: int32(grpc.Code(err)),
}
buf, merr := marshaler.Marshal(body)
if merr != nil {
grpclog.Printf("Failed to marshal error message %q: %v", body, merr)
w.WriteHeader(http.StatusInternalServerError)
if _, err := io.WriteString(w, fallback); err != nil {
grpclog.Printf("Failed to write response: %v", err)
}
return
}
md, ok := ServerMetadataFromContext(ctx)
if !ok {
grpclog.Printf("Failed to extract ServerMetadata from context")
}
handleForwardResponseServerMetadata(w, md)
handleForwardResponseTrailerHeader(w, md)
st := HTTPStatusFromCode(grpc.Code(err))
w.WriteHeader(st)
if _, err := w.Write(buf); err != nil {
grpclog.Printf("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)
}