sslobodr | d046be8 | 2019-01-16 10:02:22 -0500 | [diff] [blame] | 1 | package runtime |
| 2 | |
| 3 | import ( |
| 4 | "io" |
| 5 | "net/http" |
| 6 | |
| 7 | "context" |
| 8 | "google.golang.org/grpc/codes" |
| 9 | "google.golang.org/grpc/grpclog" |
| 10 | "google.golang.org/grpc/status" |
| 11 | ) |
| 12 | |
| 13 | // ProtoErrorHandlerFunc handles the error as a gRPC error generated via status package and replies to the request. |
| 14 | type ProtoErrorHandlerFunc func(context.Context, *ServeMux, Marshaler, http.ResponseWriter, *http.Request, error) |
| 15 | |
| 16 | var _ ProtoErrorHandlerFunc = DefaultHTTPProtoErrorHandler |
| 17 | |
| 18 | // DefaultHTTPProtoErrorHandler is an implementation of HTTPError. |
| 19 | // If "err" is an error from gRPC system, the function replies with the status code mapped by HTTPStatusFromCode. |
| 20 | // If otherwise, it replies with http.StatusInternalServerError. |
| 21 | // |
| 22 | // The response body returned by this function is a Status message marshaled by a Marshaler. |
| 23 | // |
| 24 | // Do not set this function to HTTPError variable directly, use WithProtoErrorHandler option instead. |
| 25 | func DefaultHTTPProtoErrorHandler(ctx context.Context, mux *ServeMux, marshaler Marshaler, w http.ResponseWriter, _ *http.Request, err error) { |
| 26 | // return Internal when Marshal failed |
| 27 | const fallback = `{"code": 13, "message": "failed to marshal error message"}` |
| 28 | |
| 29 | w.Header().Del("Trailer") |
| 30 | w.Header().Set("Content-Type", marshaler.ContentType()) |
| 31 | |
| 32 | s, ok := status.FromError(err) |
| 33 | if !ok { |
| 34 | s = status.New(codes.Unknown, err.Error()) |
| 35 | } |
| 36 | |
| 37 | buf, merr := marshaler.Marshal(s.Proto()) |
| 38 | if merr != nil { |
| 39 | grpclog.Infof("Failed to marshal error message %q: %v", s.Proto(), merr) |
| 40 | w.WriteHeader(http.StatusInternalServerError) |
| 41 | if _, err := io.WriteString(w, fallback); err != nil { |
| 42 | grpclog.Infof("Failed to write response: %v", err) |
| 43 | } |
| 44 | return |
| 45 | } |
| 46 | |
| 47 | md, ok := ServerMetadataFromContext(ctx) |
| 48 | if !ok { |
| 49 | grpclog.Infof("Failed to extract ServerMetadata from context") |
| 50 | } |
| 51 | |
| 52 | handleForwardResponseServerMetadata(w, mux, md) |
| 53 | handleForwardResponseTrailerHeader(w, md) |
| 54 | st := HTTPStatusFromCode(s.Code()) |
| 55 | w.WriteHeader(st) |
| 56 | if _, err := w.Write(buf); err != nil { |
| 57 | grpclog.Infof("Failed to write response: %v", err) |
| 58 | } |
| 59 | |
| 60 | handleForwardResponseTrailer(w, md) |
| 61 | } |