区块链教程Fabric1.0源代码分析流言算法Gossip服务端一，2018年下半年，区块链行业正逐渐褪去发展之初的浮躁、回归理性，表面上看相关人才需求与身价似乎正在回落。但事实上，正是初期泡沫的渐退，让人们更多的关注点放在了区块链真正的技术之上。

Fabric 1.0源代码笔记 之 gossip（流言算法） #GossipServer（Gossip服务端）

1、GossipServer概述

GossipServer相关代码，分布在protos/gossip、gossip/comm目录下。目录结构如下：

• protos/gossip目录：
      * message.pb.go，GossipClient接口定义及实现，GossipServer接口定义。
• gossip/comm目录：
      * comm.go，Comm接口定义。

    * conn.go，connFactory接口定义，以及connectionStore结构体及方法。
    * comm_impl.go，commImpl结构体及方法（同时实现GossipServer接口/Comm接口/connFactory接口）。
    * demux.go，ChannelDeMultiplexer结构体及方法。

2、GossipClient接口定义及实现

2.1、GossipClient接口定义

type GossipClient interface {     // GossipStream is the gRPC stream used for sending and receiving messages     GossipStream(ctx context.Context, opts ...grpc.CallOption) (Gossip_GossipStreamClient, error)     // Ping is used to probe a remote peer's aliveness     Ping(ctx context.Context, in *Empty, opts ...grpc.CallOption) (*Empty, error) } //代码在protos/gossip/message.pb.go

2.2、GossipClient接口实现

type gossipClient struct {     cc *grpc.ClientConn } func NewGossipClient(cc *grpc.ClientConn) GossipClient {     return &gossipClient{cc} } func (c *gossipClient) GossipStream(ctx context.Context, opts ...grpc.CallOption) (Gossip_GossipStreamClient, error) {     stream, err := grpc.NewClientStream(ctx, &_Gossip_serviceDesc.Streams[0], c.cc, "/gossip.Gossip/GossipStream", opts...)     if err != nil {         return nil, err     }     x := &gossipGossipStreamClient{stream}     return x, nil } func (c *gossipClient) Ping(ctx context.Context, in *Empty, opts ...grpc.CallOption) (*Empty, error) {     out := new(Empty)     err := grpc.Invoke(ctx, "/gossip.Gossip/Ping", in, out, c.cc, opts...)     if err != nil {         return nil, err     }     return out, nil } //代码在protos/gossip/message.pb.go

2.3、Gossip_GossipStreamClient接口定义及实现

type Gossip_GossipStreamClient interface {     Send(*Envelope) error     Recv() (*Envelope, error)     grpc.ClientStream } type gossipGossipStreamClient struct {     grpc.ClientStream } func (x *gossipGossipStreamClient) Send(m *Envelope) error {     return x.ClientStream.SendMsg(m) } func (x *gossipGossipStreamClient) Recv() (*Envelope, error) {     m := new(Envelope)     if err := x.ClientStream.RecvMsg(m); err != nil {         return nil, err     }     return m, nil } //代码在protos/gossip/message.pb.go

3、GossipServer接口定义

3.1、GossipServer接口定义

type GossipServer interface {     // GossipStream is the gRPC stream used for sending and receiving messages     GossipStream(Gossip_GossipStreamServer) error     // Ping is used to probe a remote peer's aliveness     Ping(context.Context, *Empty) (*Empty, error) } func RegisterGossipServer(s *grpc.Server, srv GossipServer) {     s.RegisterService(&_Gossip_serviceDesc, srv) } func _Gossip_GossipStream_Handler(srv interface{}, stream grpc.ServerStream) error {     return srv.(GossipServer).GossipStream(&gossipGossipStreamServer{stream}) } func _Gossip_Ping_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {     in := new(Empty)     if err := dec(in); err != nil {         return nil, err     }     if interceptor == nil {         return srv.(GossipServer).Ping(ctx, in)     }     info := &grpc.UnaryServerInfo{         Server: srv,         FullMethod: "/gossip.Gossip/Ping",     }     handler := func(ctx context.Context, req interface{}) (interface{}, error) {         return srv.(GossipServer).Ping(ctx, req.(*Empty))     }     return interceptor(ctx, in, info, handler) } var _Gossip_serviceDesc = grpc.ServiceDesc{     ServiceName: "gossip.Gossip",     HandlerType: (*GossipServer)(nil),     Methods: []grpc.MethodDesc{         {             MethodName: "Ping",             Handler: _Gossip_Ping_Handler,         },     },     Streams: []grpc.StreamDesc{         {             StreamName: "GossipStream",             Handler: _Gossip_GossipStream_Handler,             ServerStreams: true,             ClientStreams: true,         },     },     Metadata: "gossip/message.proto", } //代码在protos/gossip/message.pb.go

3.2、Gossip_GossipStreamServer接口定义及实现

type Gossip_GossipStreamServer interface {     Send(*Envelope) error     Recv() (*Envelope, error)     grpc.ServerStream } type gossipGossipStreamServer struct {     grpc.ServerStream } func (x *gossipGossipStreamServer) Send(m *Envelope) error {     return x.ServerStream.SendMsg(m) } func (x *gossipGossipStreamServer) Recv() (*Envelope, error) {     m := new(Envelope)     if err := x.ServerStream.RecvMsg(m); err != nil {         return nil, err     }     return m, nil } //代码在protos/gossip/message.pb.go

4、Comm接口/connFactory接口定义

4.1、Comm接口定义

type Comm interface {     //返回此实例的 PKI id     GetPKIid() common.PKIidType     //向节点发送消息     Send(msg *proto.SignedGossipMessage, peers ...*RemotePeer)     //探测远程节点是否有响应     Probe(peer *RemotePeer) error     //握手验证远程节点     Handshake(peer *RemotePeer) (api.PeerIdentityType, error)     Accept(common.MessageAcceptor) <-chan proto.ReceivedMessage     //获取怀疑脱机节点的只读通道     PresumedDead() <-chan common.PKIidType     //关闭到某个节点的连接     CloseConn(peer *RemotePeer)     //关闭     Stop() } //代码在gossip/comm/comm.go

4.2、connFactory接口定义

type connFactory interface {     createConnection(endpoint string, pkiID common.PKIidType) (*connection, error) } //代码在gossip/comm/conn.go

5、commImpl结构体及方法（同时实现GossipServer接口/Comm接口/connFactory接口）

5.1、commImpl结构体定义

type commImpl struct {     selfCertHash []byte     peerIdentity api.PeerIdentityType     idMapper identity.Mapper     logger *logging.Logger     opts []grpc.DialOption     secureDialOpts func() []grpc.DialOption     connStore *connectionStore     PKIID []byte     deadEndpoints chan common.PKIidType     msgPublisher *ChannelDeMultiplexer     lock *sync.RWMutex     lsnr net.Listener     gSrv *grpc.Server     exitChan chan struct{}     stopWG sync.WaitGroup     subscriptions []chan proto.ReceivedMessage     port int     stopping int32 } //代码在gossip/comm/comm_impl.go

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