Don Newton | 379ae25 | 2019-04-01 12:17:06 -0400 | [diff] [blame^] | 1 | package runtime |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "io" |
| 6 | "net/http" |
| 7 | |
| 8 | "github.com/golang/protobuf/proto" |
| 9 | "github.com/golang/protobuf/ptypes/any" |
| 10 | "google.golang.org/grpc/codes" |
| 11 | "google.golang.org/grpc/grpclog" |
| 12 | "google.golang.org/grpc/status" |
| 13 | ) |
| 14 | |
| 15 | // HTTPStatusFromCode converts a gRPC error code into the corresponding HTTP response status. |
| 16 | // See: https://github.com/googleapis/googleapis/blob/master/google/rpc/code.proto |
| 17 | func HTTPStatusFromCode(code codes.Code) int { |
| 18 | switch code { |
| 19 | case codes.OK: |
| 20 | return http.StatusOK |
| 21 | case codes.Canceled: |
| 22 | return http.StatusRequestTimeout |
| 23 | case codes.Unknown: |
| 24 | return http.StatusInternalServerError |
| 25 | case codes.InvalidArgument: |
| 26 | return http.StatusBadRequest |
| 27 | case codes.DeadlineExceeded: |
| 28 | return http.StatusGatewayTimeout |
| 29 | case codes.NotFound: |
| 30 | return http.StatusNotFound |
| 31 | case codes.AlreadyExists: |
| 32 | return http.StatusConflict |
| 33 | case codes.PermissionDenied: |
| 34 | return http.StatusForbidden |
| 35 | case codes.Unauthenticated: |
| 36 | return http.StatusUnauthorized |
| 37 | case codes.ResourceExhausted: |
| 38 | return http.StatusTooManyRequests |
| 39 | case codes.FailedPrecondition: |
| 40 | return http.StatusPreconditionFailed |
| 41 | case codes.Aborted: |
| 42 | return http.StatusConflict |
| 43 | case codes.OutOfRange: |
| 44 | return http.StatusBadRequest |
| 45 | case codes.Unimplemented: |
| 46 | return http.StatusNotImplemented |
| 47 | case codes.Internal: |
| 48 | return http.StatusInternalServerError |
| 49 | case codes.Unavailable: |
| 50 | return http.StatusServiceUnavailable |
| 51 | case codes.DataLoss: |
| 52 | return http.StatusInternalServerError |
| 53 | } |
| 54 | |
| 55 | grpclog.Infof("Unknown gRPC error code: %v", code) |
| 56 | return http.StatusInternalServerError |
| 57 | } |
| 58 | |
| 59 | var ( |
| 60 | // HTTPError replies to the request with the error. |
| 61 | // You can set a custom function to this variable to customize error format. |
| 62 | HTTPError = DefaultHTTPError |
| 63 | // OtherErrorHandler handles the following error used by the gateway: StatusMethodNotAllowed StatusNotFound and StatusBadRequest |
| 64 | OtherErrorHandler = DefaultOtherErrorHandler |
| 65 | ) |
| 66 | |
| 67 | type errorBody struct { |
| 68 | Error string `protobuf:"bytes,1,name=error" json:"error"` |
| 69 | // This is to make the error more compatible with users that expect errors to be Status objects: |
| 70 | // https://github.com/grpc/grpc/blob/master/src/proto/grpc/status/status.proto |
| 71 | // It should be the exact same message as the Error field. |
| 72 | Message string `protobuf:"bytes,1,name=message" json:"message"` |
| 73 | Code int32 `protobuf:"varint,2,name=code" json:"code"` |
| 74 | Details []*any.Any `protobuf:"bytes,3,rep,name=details" json:"details,omitempty"` |
| 75 | } |
| 76 | |
| 77 | // Make this also conform to proto.Message for builtin JSONPb Marshaler |
| 78 | func (e *errorBody) Reset() { *e = errorBody{} } |
| 79 | func (e *errorBody) String() string { return proto.CompactTextString(e) } |
| 80 | func (*errorBody) ProtoMessage() {} |
| 81 | |
| 82 | // DefaultHTTPError is the default implementation of HTTPError. |
| 83 | // If "err" is an error from gRPC system, the function replies with the status code mapped by HTTPStatusFromCode. |
| 84 | // If otherwise, it replies with http.StatusInternalServerError. |
| 85 | // |
| 86 | // The response body returned by this function is a JSON object, |
| 87 | // which contains a member whose key is "error" and whose value is err.Error(). |
| 88 | func DefaultHTTPError(ctx context.Context, mux *ServeMux, marshaler Marshaler, w http.ResponseWriter, _ *http.Request, err error) { |
| 89 | const fallback = `{"error": "failed to marshal error message"}` |
| 90 | |
| 91 | s, ok := status.FromError(err) |
| 92 | if !ok { |
| 93 | s = status.New(codes.Unknown, err.Error()) |
| 94 | } |
| 95 | |
| 96 | w.Header().Del("Trailer") |
| 97 | |
| 98 | contentType := marshaler.ContentType() |
| 99 | // Check marshaler on run time in order to keep backwards compatability |
| 100 | // An interface param needs to be added to the ContentType() function on |
| 101 | // the Marshal interface to be able to remove this check |
| 102 | if httpBodyMarshaler, ok := marshaler.(*HTTPBodyMarshaler); ok { |
| 103 | pb := s.Proto() |
| 104 | contentType = httpBodyMarshaler.ContentTypeFromMessage(pb) |
| 105 | } |
| 106 | w.Header().Set("Content-Type", contentType) |
| 107 | |
| 108 | body := &errorBody{ |
| 109 | Error: s.Message(), |
| 110 | Message: s.Message(), |
| 111 | Code: int32(s.Code()), |
| 112 | Details: s.Proto().GetDetails(), |
| 113 | } |
| 114 | |
| 115 | buf, merr := marshaler.Marshal(body) |
| 116 | if merr != nil { |
| 117 | grpclog.Infof("Failed to marshal error message %q: %v", body, merr) |
| 118 | w.WriteHeader(http.StatusInternalServerError) |
| 119 | if _, err := io.WriteString(w, fallback); err != nil { |
| 120 | grpclog.Infof("Failed to write response: %v", err) |
| 121 | } |
| 122 | return |
| 123 | } |
| 124 | |
| 125 | md, ok := ServerMetadataFromContext(ctx) |
| 126 | if !ok { |
| 127 | grpclog.Infof("Failed to extract ServerMetadata from context") |
| 128 | } |
| 129 | |
| 130 | handleForwardResponseServerMetadata(w, mux, md) |
| 131 | handleForwardResponseTrailerHeader(w, md) |
| 132 | st := HTTPStatusFromCode(s.Code()) |
| 133 | w.WriteHeader(st) |
| 134 | if _, err := w.Write(buf); err != nil { |
| 135 | grpclog.Infof("Failed to write response: %v", err) |
| 136 | } |
| 137 | |
| 138 | handleForwardResponseTrailer(w, md) |
| 139 | } |
| 140 | |
| 141 | // DefaultOtherErrorHandler is the default implementation of OtherErrorHandler. |
| 142 | // It simply writes a string representation of the given error into "w". |
| 143 | func DefaultOtherErrorHandler(w http.ResponseWriter, _ *http.Request, msg string, code int) { |
| 144 | http.Error(w, msg, code) |
| 145 | } |