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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