Method writeStatus

internal/transport/handler_server.go:228–288

(s *ServerStream, st *status.Status)

}

func (ht *serverHandlerTransport) writeStatus(s *ServerStream, st *status.Status) error {
	ht.writeStatusMu.Lock()
	defer ht.writeStatusMu.Unlock()

	headersWritten := s.updateHeaderSent()
	err := ht.do(func() {
		if !headersWritten {
			ht.writePendingHeaders(s)
		}

		// And flush, in case no header or body has been sent yet.
		// This forces a separation of headers and trailers if this is the
		// first call (for example, in end2end tests's TestNoService).
		ht.rw.(http.Flusher).Flush()

		h := ht.rw.Header()
		h.Set("Grpc-Status", fmt.Sprintf("%d", st.Code()))
		if m := st.Message(); m != "" {
			h.Set("Grpc-Message", encodeGrpcMessage(m))
		}

		s.hdrMu.Lock()
		defer s.hdrMu.Unlock()
		if p := st.Proto(); p != nil && len(p.Details) > 0 {
			delete(s.trailer, grpcStatusDetailsBinHeader)
			stBytes, err := proto.Marshal(p)
			if err != nil {
				// TODO: return error instead, when callers are able to handle it.
				panic(err)
			}

			h.Set(grpcStatusDetailsBinHeader, encodeBinHeader(stBytes))
		}

		if len(s.trailer) > 0 {
			for k, vv := range s.trailer {
				// Clients don't tolerate reading restricted headers after some non restricted ones were sent.
				if isReservedHeader(k) {
					continue
				}
				for _, v := range vv {
					// http2 ResponseWriter mechanism to send undeclared Trailers after
					// the headers have possibly been written.
					h.Add(http2.TrailerPrefix+k, encodeMetadataHeader(k, v))
				}
			}
		}
	})

	if err == nil && ht.stats != nil { // transport has not been closed
		// Note: The trailer fields are compressed with hpack after this call returns.
		// No WireLength field is set here.
		s.hdrMu.Lock()
		ht.stats.HandleRPC(s.Context(), &stats.OutTrailer{
			Trailer: s.trailer.Copy(),
		})
		s.hdrMu.Unlock()
	}