Example #1
0
//
// Synchronize with the leader.
//
func syncWithPeer(pipe *common.PeerPipe,
	handler ActionHandler,
	factory MsgFactory,
	killch <-chan bool) (success bool, isKilled bool) {

	log.Current.Debugf("WatcherServer.syncWithPeer(): Watcher start synchronization with peer (TCP %s)", pipe.GetAddr())
	proxy := NewFollowerSyncProxy(pipe, handler, factory, false)
	donech := proxy.GetDoneChannel()
	go proxy.Start()
	defer proxy.Terminate()

	// This will block until NewWatcherSyncProxy has sychronized with the peer (a bool is pushed to donech)
	select {
	case success = <-donech:
		if success {
			log.Current.Debugf("WatcherServer.syncWithPeer(): Watcher done synchronization with peer (TCP %s)", pipe.GetAddr())
		}
		return success, false
	case <-killch:
		// simply return. The pipe will eventually be closed and
		// cause WatcherSyncProxy to err out.
		log.Current.Debugf("WatcherServer.syncWithPeer(): Recieve kill singal.  Synchronization with peer (TCP %s) terminated.",
			pipe.GetAddr())
		return false, true
	}
}
Example #2
0
func send(packet common.Packet, pipe *common.PeerPipe) error {

	log.Current.Tracef("SyncProxy.send(): sending packet %s to peer (TCP %s)", packet.Name(), pipe.GetAddr())
	if !pipe.Send(packet) {
		return common.NewError(common.SERVER_ERROR, fmt.Sprintf("SyncProxy.listen(): Fail to send packet %s to peer (TCP %s)",
			packet.Name(), pipe.GetAddr()))
	}

	return nil
}
Example #3
0
//
// Synchronize with the leader.
//
func syncWithLeader(naddr string,
	pipe *common.PeerPipe,
	handler ActionHandler,
	factory MsgFactory,
	killch <-chan bool) bool {

	log.Current.Debugf("FollowerServer.syncWithLeader(): Follower %s start synchronization with leader (TCP %s)",
		naddr, pipe.GetAddr())
	proxy := NewFollowerSyncProxy(pipe, handler, factory, true)
	donech := proxy.GetDoneChannel()
	go proxy.Start()
	defer proxy.Terminate()

	// This will block until NewFollowerSyncProxy has sychronized with the leader (a bool is pushed to donech)
	select {
	case success := <-donech:
		if success {
			log.Current.Debugf("FollowerServer.syncWithLeader(): Follower %s done synchronization with leader (TCP %s)",
				naddr, pipe.GetAddr())
		}
		return success
	case <-killch:
		// simply return. The pipe will eventually be closed and
		// cause FollowerSyncProxy to err out.
		log.Current.Debugf("FollowerServer.syncWithLeader(): Recieve kill singal.  Synchronization with leader (TCP %s) terminated.",
			pipe.GetAddr())
	}

	return false
}
Example #4
0
//
// Start a LeaderSyncProxy to synchornize the leader
// and follower state.
//
func (l *LeaderServer) startProxy(peer *common.PeerPipe) {

	defer func() {
		if r := recover(); r != nil {
			log.Current.Errorf("panic in LeaderServer.startProxy() : %s\n", r)
			log.Current.Errorf("%s", log.Current.StackTrace())
		} else {
			log.Current.Debugf("LeaderServer.startProxy() : Terminates.")
			log.Current.Tracef(log.Current.StackTrace())
		}

		// deregister the proxy with the leader Server upon exit
		l.deregisterOutstandingProxy(peer.GetAddr())
	}()

	// create a proxy that will sycnhronize with the peer.
	log.Current.Debugf("LeaderServer.startProxy(): Start synchronization with follower. Peer TCP connection (%s)", peer.GetAddr())
	proxy := NewLeaderSyncProxy(l.leader, l.consentState, peer, l.handler, l.factory)
	donech := proxy.GetDoneChannel()

	// Create an observer for the leader.  The leader will put on-going proposal msg and commit msg
	// onto the observer queue.  This ensure that we can won't miss those mutations as the leader is
	// sync'ign withe follower.  The messages in observer queue will eventually route to follower.
	o := NewObserver()
	l.leader.AddObserver(peer.GetAddr(), o)
	defer l.leader.RemoveObserver(peer.GetAddr())

	// start the proxy
	go proxy.Start(o)
	defer proxy.Terminate()

	// Get the killch for this go-routine
	killch := l.getProxyKillChan(peer.GetAddr())
	if killch == nil {
		log.Current.Debugf("LeaderServer.startProxy(): Cannot find killch for proxy (TCP connection = %s).", peer.GetAddr())
		log.Current.Debugf("LeaderServer.startProxy(): Cannot start follower sync.")
		return
	}

	// this go-routine will be blocked until handshake is completed between the
	// leader and the follower.  By then, the leader will also get majority
	// confirmation that it is a leader.
	select {
	case success := <-donech:
		if success {
			// tell the leader to add this follower for processing request.  If there is a follower running already,
			// AddFollower() will terminate the existing follower instance, and then create a new one.
			fid := proxy.GetFid()
			if proxy.CanFollowerVote() {
				l.leader.AddFollower(fid, peer, o)
				log.Current.Debugf("LeaderServer.startProxy(): Synchronization with follower %s done (TCP conn = %s).  Add follower.",
					fid, peer.GetAddr())

				// At this point, the follower has voted this server as the leader.
				// Notify the request processor to start processing new request for this host
				l.notifyReady()
			} else {
				l.leader.AddWatcher(fid, peer, o)
				log.Current.Debugf("LeaderServer.startProxy(): Sync with watcher done.  Add Watcher %s (TCP conn = %s)",
					fid, peer.GetAddr())
			}
		} else {
			log.Current.Errorf("LeaderServer:startProxy(): Leader Fail to synchronization with follower (TCP conn = %s)", peer.GetAddr())
		}
	case <-killch:
		log.Current.Infof("LeaderServer:startProxy(): Sync proxy is killed while synchronizing with follower (TCP conn == %s)",
			peer.GetAddr())
	}
}