Exemple #1
0
func outgoingConn(node uint16) {

	conn, err := connect.Dial(connect.CONSENSUS_PROTOCOL, node)
	if err != nil {
		// Can't reach the other node.
		return
	}

	receivedConnCh <- receivedConn{node: node, conn: conn}

	log.Print("core/consensus: made outgoing connection to ", node)
	handleConn(node, conn)
}
Exemple #2
0
// Try to make an outgoing connection to the given node ID.
func tryOutgoing(node uint16) {

	conn, err := connect.Dial(connect.FOLLOW_PROTOCOL, node)
	if err != nil {
		// No luck connecting.
		return
	}

	log.Print("shared/follow: made new outgoing connection to ", node)

	// Send the new outgoing connection to the processing goroutine.
	followConn := new(followConn)
	followConn.node = node
	followConn.conn = conn
	followConn.outgoing = true
	receivedConnCh <- followConn
}
Exemple #3
0
// Sends the given change forward message to the given node.
// Must not be called with our own node ID.
// Does not handle adding timeouts, or adding this node ID to the ignore list.
// Must be called from the processing goroutine.
func sendForward(node uint16, forward *chproto.ChangeForward) {

	// If we don't have a connection to this node,
	// establish an outgoing connection.
	if len(connections[node]) == 0 {
		conn, err := connect.Dial(connect.CHANGE_REQUEST_PROTOCOL, node)
		if err != nil {
			// Message is dropped.
			return
		}

		log.Print("shared/chrequest: made new outgoing conn to node ",
			node)

		connections[node] = append(connections[node], conn)
		go handleConn(node, conn)
	}

	connections[node][0].SendProto(2, forward)
}
Exemple #4
0
// Top-level function of the processing goroutine.
func process() {

	connections = make(map[uint16][]*connect.BaseConn)

	// On startup, make an outgoing connection attempt to all other
	// core nodes, before continuing.
	for _, node := range config.CoreNodes() {
		if node == config.Id() {
			continue
		}

		conn, err := connect.Dial(
			connect.CONSENSUS_PROTOCOL, node)
		if err != nil {
			// Can't reach the other node.
			continue
		}

		log.Print("core/consensus: made outgoing connection to ", node)
		connections[node] = append(connections[node], conn)
		go handleConn(node, conn)
	}

	// Retry connections once per config.CHANGE_TIMEOUT_PERIOD.
	// Largely arbitrary.
	reconnectTicker := time.Tick(config.CHANGE_TIMEOUT_PERIOD)

	for {
		select {

		// Connection retry tick.
		// We should try to make an outgoing connection to any node
		// that we do not have at least one connection to.
		// We need to make these asynchronously, because connections
		// are slow.
		case <-reconnectTicker:
			for _, node := range config.CoreNodes() {
				if node == config.Id() {
					continue
				}
				if len(connections[node]) > 0 {
					continue
				}

				go outgoingConn(node)
			}

		// New change request, for us to propose as leader.
		case req := <-newChangeCh:

			store.StartTransaction()

			if !amLeader && receivedPromises != nil {
				waitingRequests = append(waitingRequests, req)
			} else if !amLeader {
				waitingRequests = append(waitingRequests, req)

				// Start attempting to be leader.
				m := make(map[uint16]*coproto.Promise)
				receivedPromises = m

				proposal, _ := store.Proposal()
				proposal++
				store.SetProposal(proposal, config.Id())
				firstUn := store.InstructionFirstUnapplied()

				// Send prepare messages to all other nodes.
				var prepare coproto.Prepare
				prepare.Proposal = new(uint64)
				prepare.FirstUnapplied = new(uint64)
				*prepare.Proposal = proposal
				*prepare.FirstUnapplied = firstUn

				for _, node := range config.CoreNodes() {
					if node == config.Id() {
						continue
					}

					if len(connections[node]) != 0 {
						c := connections[node][0]
						c.SendProto(2, &prepare)
					}
				}

				// Behave as if we got a promise message
				// from ourselves.
				var promise coproto.Promise
				promise.Proposal = prepare.Proposal
				promise.PrevProposal = promise.Proposal
				promise.Leader = new(uint32)
				*promise.Leader = uint32(config.Id())
				promise.PrevLeader = promise.Leader
				addPromise(config.Id(), &promise)
			} else {
				newSlot := nextProposalSlot
				nextProposalSlot++

				addProposalTimeout(newSlot, req)

				proposal, leader := store.Proposal()
				inst := makeInst(newSlot, proposal, leader,
					req)

				sendProposal(inst)
			}

			store.EndTransaction()

		// Leadership attempt timed out.
		case timedOutProposal := <-leaderTimeoutCh:

			store.StartTransaction()

			proposal, leader := store.Proposal()

			// If the proposal has changed since that
			// leadership attempt, ignore it.
			if leader != config.Id() {
				return
			}
			if proposal != timedOutProposal {
				return
			}

			// If we successfully became leader, ignore it.
			if amLeader {
				return
			}

			// Otherwise, stop our attempt to become leader.
			stopBeingLeader()

			store.EndTransaction()

		// Proposal timed out.
		case timeout := <-proposalTimeoutCh:

			store.StartTransaction()

			// If this timeout was not canceled, a proposal failed.
			// We stop being leader.
			if proposalTimeouts[timeout.slot] == timeout {
				stopBeingLeader()
			}

			store.EndTransaction()

		// New received connection.
		case receivedConn := <-receivedConnCh:
			node := receivedConn.node
			conn := receivedConn.conn

			connections[node] = append(connections[node], conn)

		// Received message.
		case recvMsg := <-receivedMsgCh:
			node := recvMsg.node
			conn := recvMsg.conn
			msg := recvMsg.msg

			switch *msg.MsgType {
			case 2:
				processPrepare(node, conn, msg.Content)
			case 3:
				processPromise(node, conn, msg.Content)
			case 4:
				processAccept(node, conn, msg.Content)
			case 5:
				processAccepted(node, conn, msg.Content)
			case 6:
				processNack(node, conn, msg.Content)
			default:
				// Unknown message.
				conn.Close()
			}

		// Terminate received connection.
		case terminatedConn := <-terminatedConnCh:
			node := terminatedConn.node
			conn := terminatedConn.conn

			for i, other := range connections[node] {
				if other != conn {
					continue
				}

				conns := connections[node]
				conns = append(conns[:i], conns[i+1:]...)
				connections[node] = conns
				break
			}
		}
	}
}
Exemple #5
0
func process() {

	// Try to make an outgoing connection to all other client nodes,
	// if we're not in a degraded state.
	store.StartTransaction()
	if !store.Degraded() {

		for _, node := range config.ClientNodes() {
			if node == config.Id() {
				continue
			}

			conn, err := connect.Dial(connect.RELAY_PROTOCOL, node)
			if err != nil {
				// No luck connecting.
				continue
			}

			connections[node] = append(connections[node], conn)
			go handleConn(node, conn)
		}
	}
	store.EndTransaction()

	// Retry connections once per config.CHANGE_TIMEOUT_PERIOD
	// Largely arbitrary.
	reconnectTicker := time.Tick(config.CHANGE_TIMEOUT_PERIOD)

	for {
		select {

		// Connection retry tick.
		// If not degraded, try to make an outgoing connection to any
		// client node that we do not have at least one connection to.
		case <-reconnectTicker:

			store.StartTransaction()

			// Do not attempt to make connections while degraded.
			if store.Degraded() {
				store.EndTransaction()
				break
			}

			for _, node := range config.ClientNodes() {
				if node == config.Id() {
					continue
				}
				if len(connections[node]) > 0 {
					continue
				}

				conn, err := connect.Dial(
					connect.RELAY_PROTOCOL, node)

				if err != nil {
					// No luck connecting.
					continue
				}

				connections[node] =
					append(connections[node], conn)
				go handleConn(node, conn)
			}

			store.EndTransaction()

		// New received connection.
		case receivedConn := <-receivedConnCh:
			node := receivedConn.node
			conn := receivedConn.conn

			store.StartTransaction()

			// If we are degraded, reject the connection.
			if store.Degraded() {
				conn.Close()
				store.EndTransaction()
				break
			}

			// Add to our connections.
			connections[node] = append(connections[node], conn)

			store.EndTransaction()

		// Terminated connection.
		case receivedConn := <-terminatedConnCh:
			node := receivedConn.node
			conn := receivedConn.conn

			store.StartTransaction()

			// Remove this connection from our connection list.
			index := -1
			for i, _ := range connections[node] {
				if conn == connections[node][i] {
					index = i
					break
				}
			}
			if index != -1 {
				connections[node] =
					append(connections[node][:index],
						connections[node][index+1:]...)
			}

			store.EndTransaction()
		}
	}
}