Exemple #1
0
// TODO: change etcdserver to raft interface when we have it.
//       add test for healthHandler when we have the interface ready.
func healthHandler(server *etcdserver.EtcdServer) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if !allowMethod(w, r.Method, "GET") {
			return
		}

		if uint64(server.Leader()) == raft.None {
			http.Error(w, `{"health": "false"}`, http.StatusServiceUnavailable)
			return
		}

		// wait for raft's progress
		index := server.Index()
		for i := 0; i < 3; i++ {
			time.Sleep(250 * time.Millisecond)
			if server.Index() > index {
				w.WriteHeader(http.StatusOK)
				w.Write([]byte(`{"health": "true"}`))
				return
			}
		}

		http.Error(w, `{"health": "false"}`, http.StatusServiceUnavailable)
		return
	}
}
Exemple #2
0
func newStreamInterceptor(s *etcdserver.EtcdServer) grpc.StreamServerInterceptor {
	smap := monitorLeader(s)

	return func(srv interface{}, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
		if !api.IsCapabilityEnabled(api.V3rpcCapability) {
			return rpctypes.ErrGRPCNotCapable
		}

		md, ok := metadata.FromContext(ss.Context())
		if ok {
			if ks := md[rpctypes.MetadataRequireLeaderKey]; len(ks) > 0 && ks[0] == rpctypes.MetadataHasLeader {
				if s.Leader() == types.ID(raft.None) {
					return rpctypes.ErrGRPCNoLeader
				}

				cctx, cancel := context.WithCancel(ss.Context())
				ss = serverStreamWithCtx{ctx: cctx, cancel: &cancel, ServerStream: ss}

				smap.mu.Lock()
				smap.streams[ss] = struct{}{}
				smap.mu.Unlock()

				defer func() {
					smap.mu.Lock()
					delete(smap.streams, ss)
					smap.mu.Unlock()
					cancel()
				}()

			}
		}
		return metricsStreamInterceptor(srv, ss, info, handler)
	}
}
Exemple #3
0
func newUnaryInterceptor(s *etcdserver.EtcdServer) grpc.UnaryServerInterceptor {
	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (resp interface{}, err error) {
		if !api.IsCapabilityEnabled(api.V3rpcCapability) {
			return nil, rpctypes.ErrGRPCNotCapable
		}

		md, ok := metadata.FromContext(ctx)
		if ok {
			if ks := md[rpctypes.MetadataRequireLeaderKey]; len(ks) > 0 && ks[0] == rpctypes.MetadataHasLeader {
				if s.Leader() == types.ID(raft.None) {
					return nil, rpctypes.ErrGRPCNoLeader
				}
			}
		}
		return metricsUnaryInterceptor(ctx, req, info, handler)
	}
}
Exemple #4
0
func monitorLeader(s *etcdserver.EtcdServer) *streamsMap {
	smap := &streamsMap{
		streams: make(map[grpc.ServerStream]struct{}),
	}

	go func() {
		election := time.Duration(s.Cfg.TickMs) * time.Duration(s.Cfg.ElectionTicks) * time.Millisecond
		noLeaderCnt := 0

		for {
			select {
			case <-s.StopNotify():
				return
			case <-time.After(election):
				if s.Leader() == types.ID(raft.None) {
					noLeaderCnt++
				} else {
					noLeaderCnt = 0
				}

				// We are more conservative on canceling existing streams. Reconnecting streams
				// cost much more than just rejecting new requests. So we wait until the member
				// cannot find a leader for maxNoLeaderCnt election timeouts to cancel existing streams.
				if noLeaderCnt >= maxNoLeaderCnt {
					smap.mu.Lock()
					for ss := range smap.streams {
						if ssWithCtx, ok := ss.(serverStreamWithCtx); ok {
							(*ssWithCtx.cancel)()
							<-ss.Context().Done()
						}
					}
					smap.streams = make(map[grpc.ServerStream]struct{})
					smap.mu.Unlock()
				}
			}
		}
	}()

	return smap
}