Ejemplo n.º 1
0
// Must be called from the processing goroutine.
func processAccept(node uint16, conn *connect.BaseConn, content []byte) {
	var msg coproto.Accept
	if err := proto.Unmarshal(content, &msg); err != nil {
		conn.Close()
		return
	}

	store.StartTransaction()
	defer store.EndTransaction()

	proposal, leader := store.Proposal()
	msgProposal, msgLeader := *msg.Proposal, node
	if proposal != msgProposal || leader != msgLeader {
		// Send a nack message and return,
		// if this accept relates to an earlier proposal.
		if store.CompareProposals(proposal, leader, msgProposal,
			msgLeader) {

			var nack coproto.Nack
			nack.Proposal = new(uint64)
			nack.Leader = new(uint32)
			*nack.Proposal = proposal
			*nack.Leader = uint32(leader)
			conn.SendProto(6, &nack)

			return
		}

		store.SetProposal(msgProposal, msgLeader)
	}

	addAccept(node, &msg)
}
Ejemplo n.º 2
0
// Must be called from the processing goroutine.
func processPrepare(node uint16, conn *connect.BaseConn, content []byte) {
	var msg coproto.Prepare
	if err := proto.Unmarshal(content, &msg); err != nil {
		conn.Close()
		return
	}

	store.StartTransaction()
	defer store.EndTransaction()

	newProposal, newLeader := *msg.Proposal, node
	proposal, leader := store.Proposal()
	if store.CompareProposals(newProposal, newLeader, proposal, leader) {

		log.Print("core/consensus: sending promise to ", newLeader)

		// Create a promise message to send back.
		var promise coproto.Promise
		promise.Proposal = new(uint64)
		promise.Leader = new(uint32)
		promise.PrevProposal = new(uint64)
		promise.PrevLeader = new(uint32)
		*promise.Proposal = newProposal
		*promise.Leader = uint32(newLeader)
		*promise.PrevProposal = proposal
		*promise.PrevLeader = uint32(leader)

		// Add all the instructions we've previously accepted or chosen.
		slots := store.InstructionSlots()
		theirFirstUnapplied := *msg.FirstUnapplied
		ourStart := store.InstructionStart()
		relativeSlot := int(theirFirstUnapplied - ourStart)
		if relativeSlot < 0 {
			relativeSlot = 0
		}
		var accepted []*coproto.Instruction
		for ; relativeSlot < len(slots); relativeSlot++ {
			slot := slots[relativeSlot]
			slotNum := ourStart + uint64(relativeSlot)
			for i, _ := range slot {
				if slot[i].IsChosen() {
					appendInst(&accepted, slotNum, slot[i])
					break
				}

				weAccepted := false
				for _, node := range slot[i].Accepted() {
					if node == config.Id() {
						weAccepted = true
						break
					}
				}

				if weAccepted {
					appendInst(&accepted, slotNum, slot[i])
					break
				}
			}
		}

		// Send promise message.
		conn.SendProto(3, &promise)

		// Accept the other node as our new leader.
		store.SetProposal(newProposal, newLeader)
	} else {
		var nack coproto.Nack
		nack.Proposal = new(uint64)
		nack.Leader = new(uint32)
		*nack.Proposal = proposal
		*nack.Leader = uint32(leader)
		conn.SendProto(6, &nack)
	}
}