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

5.2、commImpl结构体方法

//conn.serviceConnection()，启动连接服务
func (c *commImpl) GossipStream(stream proto.Gossip_GossipStreamServer) error
//return &proto.Empty{}
func (c *commImpl) Ping(context.Context, *proto.Empty) (*proto.Empty, error)

func (c *commImpl) GetPKIid() common.PKIidType
//向指定节点发送消息
func (c *commImpl) Send(msg *proto.SignedGossipMessage, peers ...*RemotePeer)
//探测远程节点是否有响应，_, err = cl.Ping(context.Background(), &proto.Empty{})
func (c *commImpl) Probe(remotePeer *RemotePeer) error
//握手验证远程节点，_, err = cl.Ping(context.Background(), &proto.Empty{})
func (c *commImpl) Handshake(remotePeer *RemotePeer) (api.PeerIdentityType, error)
func (c *commImpl) Accept(acceptor common.MessageAcceptor) <-chan proto.ReceivedMessage
func (c *commImpl) PresumedDead() <-chan common.PKIidType
func (c *commImpl) CloseConn(peer *RemotePeer)
func (c *commImpl) Stop()

//创建并启动gRPC Server，以及注册GossipServer实例
func NewCommInstanceWithServer(port int, idMapper identity.Mapper, peerIdentity api.PeerIdentityType,
//将GossipServer实例注册至peerServer
func NewCommInstance(s *grpc.Server, cert *tls.Certificate, idStore identity.Mapper,
func extractRemoteAddress(stream stream) string
func readWithTimeout(stream interface{}, timeout time.Duration, address string) (*proto.SignedGossipMessage, error) 
//创建gRPC Server，grpc.NewServer(serverOpts...)
func createGRPCLayer(port int) (*grpc.Server, net.Listener, api.PeerSecureDialOpts, []byte)

//创建与服务端连接
func (c *commImpl) createConnection(endpoint string, expectedPKIID common.PKIidType) (*connection, error)
//向指定节点发送消息
func (c *commImpl) sendToEndpoint(peer *RemotePeer, msg *proto.SignedGossipMessage)
//return atomic.LoadInt32(&c.stopping) == int32(1)
func (c *commImpl) isStopping() bool
func (c *commImpl) emptySubscriptions()
func (c *commImpl) authenticateRemotePeer(stream stream) (*proto.ConnectionInfo, error)
func (c *commImpl) disconnect(pkiID common.PKIidType)
func (c *commImpl) createConnectionMsg(pkiID common.PKIidType, certHash []byte, cert api.PeerIdentityType, signer proto.Signer) (*proto.SignedGossipMessage, error)
//代码在gossip/comm/comm_impl.go

5.2.1、func NewCommInstanceWithServer(port int, idMapper identity.Mapper, peerIdentity api.PeerIdentityType,secureDialOpts api.PeerSecureDialOpts, dialOpts ...grpc.DialOption) (Comm, error)

创建并启动gRPC Server，以及注册GossipServer实例

func NewCommInstanceWithServer(port int, idMapper identity.Mapper, peerIdentity api.PeerIdentityType,
????secureDialOpts api.PeerSecureDialOpts, dialOpts ...grpc.DialOption) (Comm, error) {

????var ll net.Listener
????var s *grpc.Server
????var certHash []byte

????if len(dialOpts) == 0 {
????????//peer.gossip.dialTimeout，gRPC连接拨号的超时
????????dialOpts = []grpc.DialOption{grpc.WithTimeout(util.GetDurationOrDefault("peer.gossip.dialTimeout", defDialTimeout))}
????}

????if port > 0 {
????????//创建gRPC Server，grpc.NewServer(serverOpts...)
????????s, ll, secureDialOpts, certHash = createGRPCLayer(port)
????}

????commInst := &commImpl{
????????selfCertHash:   certHash,
????????PKIID:          idMapper.GetPKIidOfCert(peerIdentity),
????????idMapper:       idMapper,
????????logger:         util.GetLogger(util.LoggingCommModule, fmt.Sprintf("%d", port)),
????????peerIdentity:   peerIdentity,
????????opts:           dialOpts,
????????secureDialOpts: secureDialOpts,
????????port:           port,
????????lsnr:           ll,
????????gSrv:           s,
????????msgPublisher:   NewChannelDemultiplexer(),
????????lock:           &sync.RWMutex{},
????????deadEndpoints:  make(chan common.PKIidType, 100),
????????stopping:       int32(0),
????????exitChan:       make(chan struct{}, 1),
????????subscriptions:  make([]chan proto.ReceivedMessage, 0),
????}
????commInst.connStore = newConnStore(commInst, commInst.logger)

????if port > 0 {
????????commInst.stopWG.Add(1)
????????go func() {
????????????defer commInst.stopWG.Done()
????????????s.Serve(ll) //启动gRPC Server
????????}()
????????//commInst注册到gRPC Server
????????proto.RegisterGossipServer(s, commInst)
????}

????return commInst, nil
}

//代码在gossip/comm/comm_impl.go

5.2.2、func NewCommInstance(s grpc.Server, cert tls.Certificate, idStore identity.Mapper,peerIdentity api.PeerIdentityType, secureDialOpts api.PeerSecureDialOpts,dialOpts ...grpc.DialOption) (Comm, error)

将GossipServer实例注册至peerServer

func NewCommInstance(s *grpc.Server, cert *tls.Certificate, idStore identity.Mapper,
????peerIdentity api.PeerIdentityType, secureDialOpts api.PeerSecureDialOpts,
????dialOpts ...grpc.DialOption) (Comm, error) {

????dialOpts = append(dialOpts, grpc.WithTimeout(util.GetDurationOrDefault("peer.gossip.dialTimeout", defDialTimeout)))
????//构造commImpl
????commInst, err := NewCommInstanceWithServer(-1, idStore, peerIdentity, secureDialOpts, dialOpts...)

????if cert != nil {
????????inst := commInst.(*commImpl)
????????inst.selfCertHash = certHashFromRawCert(cert.Certificate[0])
????}
????proto.RegisterGossipServer(s, commInst.(*commImpl))

????return commInst, nil
}

//代码在gossip/comm/comm_impl.go

//创建与服务端连接

5.2.3、func (c commImpl) createConnection(endpoint string, expectedPKIID common.PKIidType) (connection, error)

func (c *commImpl) createConnection(endpoint string, expectedPKIID common.PKIidType) (*connection, error) {
????var err error
????var cc *grpc.ClientConn
????var stream proto.Gossip_GossipStreamClient
????var pkiID common.PKIidType
????var connInfo *proto.ConnectionInfo
????var dialOpts []grpc.DialOption

????dialOpts = append(dialOpts, c.secureDialOpts()...)
????dialOpts = append(dialOpts, grpc.WithBlock())
????dialOpts = append(dialOpts, c.opts...)
????cc, err = grpc.Dial(endpoint, dialOpts...)

????cl := proto.NewGossipClient(cc)
????if _, err = cl.Ping(context.Background(), &proto.Empty{}); err != nil {
????????cc.Close()
????????return nil, err
????}

????ctx, cf := context.WithCancel(context.Background())
????stream, err = cl.GossipStream(ctx)
????connInfo, err = c.authenticateRemotePeer(stream)
????pkiID = connInfo.ID
????conn := newConnection(cl, cc, stream, nil)
????conn.pkiID = pkiID
????conn.info = connInfo
????conn.logger = c.logger
????conn.cancel = cf

????h := func(m *proto.SignedGossipMessage) {
????????c.msgPublisher.DeMultiplex(&ReceivedMessageImpl{
????????????conn:                conn,
????????????lock:                conn,
????????????SignedGossipMessage: m,
????????????connInfo:            connInfo,
????????})
????}
????conn.handler = h
????return conn, nil
}
//代码在gossip/comm/comm_impl.go

6、connectionStore和connection结构体及方法

6.1、connection结构体及方法

type connection struct {
????cancel       context.CancelFunc
????info         *proto.ConnectionInfo
????outBuff      chan *msgSending
????logger       *logging.Logger                 // logger
????pkiID        common.PKIidType                // pkiID of the remote endpoint
????handler      handler                         // function to invoke upon a message reception
????conn         *grpc.ClientConn                // gRPC connection to remote endpoint
????cl           proto.GossipClient              // gRPC stub of remote endpoint
????clientStream proto.Gossip_GossipStreamClient // client-side stream to remote endpoint
????serverStream proto.Gossip_GossipStreamServer // server-side stream to remote endpoint
????stopFlag     int32                           // indicates whether this connection is in process of stopping
????stopChan     chan struct{}                   // a method to stop the server-side gRPC call from a different go-routine
????sync.RWMutex                                 // synchronizes access to shared variables
}

//构造connection
func newConnection(cl proto.GossipClient, c *grpc.ClientConn, cs proto.Gossip_GossipStreamClient, ss proto.Gossip_GossipStreamServer) *connection
//关闭connection
func (conn *connection) close()
//atomic.LoadInt32(&(conn.stopFlag)) == int32(1)
func (conn *connection) toDie() bool
//conn.outBuff <- m，其中m为msgSending{envelope: msg.Envelope,onErr: onErr,}
func (conn *connection) send(msg *proto.SignedGossipMessage, onErr func(error))
//go conn.readFromStream(errChan, msgChan)、go conn.writeToStream()，同时msg := <-msgChan，conn.handler(msg)
func (conn *connection) serviceConnection() error
//循环不间断从conn.outBuff取数据，然后stream.Send(m.envelope)
func (conn *connection) writeToStream()
//循环不间断envelope, err := stream.Recv()、msg, err := envelope.ToGossipMessage()、msgChan <- msg
func (conn *connection) readFromStream(errChan chan error, msgChan chan *proto.SignedGossipMessage)
//获取conn.serverStream
func (conn *connection) getStream() stream
//代码在gossip/comm/conn.go

6.2、connectionStore结构体及方法

type connectionStore struct {
????logger           *logging.Logger          // logger
????isClosing        bool                     // whether this connection store is shutting down
????connFactory      connFactory              // creates a connection to remote peer
????sync.RWMutex                              // synchronize access to shared variables
????pki2Conn         map[string]*connection   //connection map, key为pkiID，value为connection
????destinationLocks map[string]*sync.RWMutex //mapping between pkiIDs and locks,
????// used to prevent concurrent connection establishment to the same remote endpoint
}

//构造connectionStore
func newConnStore(connFactory connFactory, logger *logging.Logger) *connectionStore
//从connection map中获取连接，如无则创建并启动连接，并写入connection map中
func (cs *connectionStore) getConnection(peer *RemotePeer) (*connection, error)
//连接数量
func (cs *connectionStore) connNum() int
//关闭指定连接
func (cs *connectionStore) closeConn(peer *RemotePeer)
//关闭所有连接
func (cs *connectionStore) shutdown()
func (cs *connectionStore) onConnected(serverStream proto.Gossip_GossipStreamServer, connInfo *proto.ConnectionInfo) *connection
//注册连接
func (cs *connectionStore) registerConn(connInfo *proto.ConnectionInfo, serverStream proto.Gossip_GossipStreamServer) *connection
//关闭指定连接
func (cs *connectionStore) closeByPKIid(pkiID common.PKIidType) 
//代码在gossip/comm/conn.go

6.2.1、func (cs connectionStore) getConnection(peer RemotePeer) (*connection, error)

func (cs *connectionStore) getConnection(peer *RemotePeer) (*connection, error) {
????cs.RLock()
????isClosing := cs.isClosing
????cs.RUnlock()

????pkiID := peer.PKIID
????endpoint := peer.Endpoint

????cs.Lock()
????destinationLock, hasConnected := cs.destinationLocks[string(pkiID)]
????if !hasConnected {
????????destinationLock = &sync.RWMutex{}
????????cs.destinationLocks[string(pkiID)] = destinationLock
????}
????cs.Unlock()

????destinationLock.Lock()
????cs.RLock()
????//从connection map中获取
????conn, exists := cs.pki2Conn[string(pkiID)]
????if exists {
????????cs.RUnlock()
????????destinationLock.Unlock()
????????return conn, nil
????}
????cs.RUnlock()

????//创建连接
????createdConnection, err := cs.connFactory.createConnection(endpoint, pkiID)
????destinationLock.Unlock()

????conn = createdConnection
????cs.pki2Conn[string(createdConnection.pkiID)] = conn
????go conn.serviceConnection() //启动连接的消息接收处理、以及向对方节点发送消息

????return conn, nil
}
//代码在gossip/comm/conn.go

7、ChannelDeMultiplexer结构体及方法（多路复用器）

type ChannelDeMultiplexer struct {
????channels []*channel
????lock     *sync.RWMutex
????closed   int32
}

//构造ChannelDeMultiplexer
func NewChannelDemultiplexer() *ChannelDeMultiplexer
//atomic.LoadInt32(&m.closed) == int32(1)
func (m *ChannelDeMultiplexer) isClosed() bool
//关闭
func (m *ChannelDeMultiplexer) Close() 
//添加通道
func (m *ChannelDeMultiplexer) AddChannel(predicate common.MessageAcceptor) chan interface{} 
//挨个通道发送消息
func (m *ChannelDeMultiplexer) DeMultiplex(msg interface{}) 

区块链教程Fabric1.0源代码分析流言算法Gossip服务端二

原文：http://blog.51cto.com/14041296/2311323