mirror of
https://github.com/etcd-io/etcd.git
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raft: clean stateMachine
This commit is contained in:
Xiang Li
Yicheng Qin
parent
5b052e1e10
commit
c223eca938
@ -13,7 +13,7 @@ type Node struct {
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func New(k, addr int, next Interface) *Node {
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n := &Node{
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sm: newStateMachine(k, addr, next),
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sm: newStateMachine(k, addr),
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}
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return n
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}
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56
raft/raft.go
56
raft/raft.go
@ -108,15 +108,15 @@ type stateMachine struct {
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votes map[int]bool
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next Interface
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msgs []Message
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// the leader addr
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lead int
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}
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func newStateMachine(k, addr int, next Interface) *stateMachine {
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func newStateMachine(k, addr int) *stateMachine {
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log := make([]Entry, 1, 1024)
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sm := &stateMachine{k: k, addr: addr, next: next, log: log}
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sm := &stateMachine{k: k, addr: addr, log: log}
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sm.reset()
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return sm
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}
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@ -145,6 +145,14 @@ func (sm *stateMachine) append(after int, ents ...Entry) int {
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return len(sm.log) - 1
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}
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func (sm *stateMachine) maybeAppend(index, logTerm int, ents ...Entry) bool {
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if sm.isLogOk(index, logTerm) {
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sm.append(index, ents...)
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return true
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}
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return false
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}
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func (sm *stateMachine) isLogOk(i, term int) bool {
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if i > sm.li() {
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return false
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@ -152,11 +160,11 @@ func (sm *stateMachine) isLogOk(i, term int) bool {
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return sm.log[i].Term == term
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}
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// send persists state to stable storage and then sends m over the network to m.To
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// send persists state to stable storage and then sends to its mailbox
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func (sm *stateMachine) send(m Message) {
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m.From = sm.addr
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m.Term = sm.term
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sm.next.Step(m)
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sm.msgs = append(sm.msgs, m)
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}
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// sendAppend sends RRPC, with entries to all peers that are not up-to-date according to sm.mis.
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@ -233,14 +241,39 @@ func (sm *stateMachine) becomeFollower(term, lead int) {
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sm.state = stateFollower
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}
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func (sm *stateMachine) becomeCandidate() {
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// TODO(xiangli) remove the panic when the raft implementation is stable
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if sm.state == stateLeader {
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panic("invalid transition [leader -> candidate]")
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}
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sm.reset()
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sm.term++
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sm.vote = sm.addr
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sm.state = stateCandidate
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sm.poll(sm.addr, true)
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}
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func (sm *stateMachine) becomeLeader() {
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// TODO(xiangli) remove the panic when the raft implementation is stable
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if sm.state == stateFollower {
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panic("invalid transition [follower -> leader]")
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}
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sm.reset()
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sm.lead = sm.addr
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sm.state = stateLeader
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}
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func (sm *stateMachine) Msgs() []Message {
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msgs := sm.msgs
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sm.msgs = make([]Message, 0)
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return msgs
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}
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func (sm *stateMachine) Step(m Message) {
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switch m.Type {
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case msgHup:
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sm.term++
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sm.reset()
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sm.state = stateCandidate
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sm.vote = sm.addr
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sm.poll(sm.addr, true)
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sm.becomeCandidate()
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for i := 0; i < sm.k; i++ {
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if i == sm.addr {
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continue
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@ -301,8 +334,7 @@ func (sm *stateMachine) Step(m Message) {
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gr := sm.poll(m.From, m.Index >= 0)
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switch sm.q() {
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case gr:
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sm.state = stateLeader
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sm.lead = sm.addr
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sm.becomeLeader()
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sm.sendAppend()
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case len(sm.votes) - gr:
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sm.becomeFollower(sm.term, none)
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@ -23,9 +23,9 @@ func TestLeaderElection(t *testing.T) {
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{
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newNetwork(
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nil,
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&stateMachine{log: []Entry{{}, {Term: 1}}},
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&stateMachine{log: []Entry{{}, {Term: 2}}},
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&stateMachine{log: []Entry{{}, {Term: 1}, {Term: 3}}},
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&nsm{stateMachine{log: []Entry{{}, {Term: 1}}}, nil},
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&nsm{stateMachine{log: []Entry{{}, {Term: 2}}}, nil},
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&nsm{stateMachine{log: []Entry{{}, {Term: 1}, {Term: 3}}}, nil},
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nil,
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),
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stateFollower,
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@ -34,10 +34,10 @@ func TestLeaderElection(t *testing.T) {
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// logs converge
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{
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newNetwork(
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&stateMachine{log: []Entry{{}, {Term: 1}}},
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&nsm{stateMachine{log: []Entry{{}, {Term: 1}}}, nil},
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nil,
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&stateMachine{log: []Entry{{}, {Term: 2}}},
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&stateMachine{log: []Entry{{}, {Term: 1}}},
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&nsm{stateMachine{log: []Entry{{}, {Term: 2}}}, nil},
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&nsm{stateMachine{log: []Entry{{}, {Term: 1}}}, nil},
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nil,
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),
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stateLeader,
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@ -46,7 +46,7 @@ func TestLeaderElection(t *testing.T) {
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for i, tt := range tests {
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tt.Step(Message{To: 0, Type: msgHup})
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sm := tt.network.ss[0].(*stateMachine)
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sm := tt.network.ss[0].(*nsm)
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if sm.state != tt.state {
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t.Errorf("#%d: state = %s, want %s", i, sm.state, tt.state)
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}
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@ -57,8 +57,8 @@ func TestLeaderElection(t *testing.T) {
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}
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func TestDualingCandidates(t *testing.T) {
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a := &stateMachine{log: defaultLog}
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c := &stateMachine{log: defaultLog}
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a := &nsm{stateMachine{log: defaultLog}, nil}
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c := &nsm{stateMachine{log: defaultLog}, nil}
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tt := newNetwork(a, nil, c)
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@ -82,7 +82,7 @@ func TestDualingCandidates(t *testing.T) {
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tt.Step(Message{To: 2, Type: msgHup})
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tests := []struct {
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sm *stateMachine
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sm *nsm
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state stateType
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term int
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}{
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@ -106,7 +106,7 @@ func TestDualingCandidates(t *testing.T) {
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}
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func TestCandidateConcede(t *testing.T) {
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a := &stateMachine{log: defaultLog}
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a := &nsm{stateMachine{log: defaultLog}, nil}
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tt := newNetwork(a, nil, nil)
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tt.tee = stepperFunc(func(m Message) {
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@ -143,7 +143,7 @@ func TestOldMessages(t *testing.T) {
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tt := newNetwork(nil, nil, nil)
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// make 0 leader @ term 3
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tt.Step(Message{To: 0, Type: msgHup})
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tt.Step(Message{To: 0, Type: msgHup})
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tt.Step(Message{To: 1, Type: msgHup})
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tt.Step(Message{To: 0, Type: msgHup})
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// pretend we're an old leader trying to make progress
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tt.Step(Message{To: 0, Type: msgApp, Term: 1, Entries: []Entry{{Term: 1}}})
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@ -204,7 +204,7 @@ func TestProposal(t *testing.T) {
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t.Errorf("#%d: diff:%s", i, diff)
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}
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}
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sm := tt.network.ss[0].(*stateMachine)
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sm := tt.network.ss[0].(*nsm)
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if g := sm.term; g != 1 {
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t.Errorf("#%d: term = %d, want %d", i, g, 1)
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}
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@ -235,7 +235,7 @@ func TestProposalByProxy(t *testing.T) {
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t.Errorf("#%d: bad entry: %s", i, diff)
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}
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}
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sm := tt.ss[0].(*stateMachine)
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sm := tt.ss[0].(*nsm)
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if g := sm.term; g != 1 {
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t.Errorf("#%d: term = %d, want %d", i, g, 1)
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}
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@ -305,7 +305,7 @@ func TestVote(t *testing.T) {
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for i, tt := range tests {
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called := false
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sm := &stateMachine{log: []Entry{{}, {Term: 2}, {Term: 2}}}
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sm := &nsm{stateMachine{log: []Entry{{}, {Term: 2}, {Term: 2}}}, nil}
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sm.next = stepperFunc(func(m Message) {
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called = true
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if m.Index != tt.w {
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@ -319,6 +319,46 @@ func TestVote(t *testing.T) {
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}
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}
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func TestAllServerStepdown(t *testing.T) {
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tests := []stateType{stateFollower, stateCandidate, stateLeader}
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want := struct {
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state stateType
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term int
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index int
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}{stateFollower, 3, 1}
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tmsgTypes := [...]messageType{msgVote, msgApp}
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tterm := 3
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for i, tt := range tests {
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sm := newStateMachine(3, 0)
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switch tt {
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case stateFollower:
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sm.becomeFollower(1, 0)
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case stateCandidate:
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sm.becomeCandidate()
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case stateLeader:
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sm.becomeCandidate()
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sm.becomeLeader()
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}
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for j, msgType := range tmsgTypes {
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sm.Step(Message{Type: msgType, Term: tterm, LogTerm: tterm})
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if sm.state != want.state {
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t.Errorf("#%d.%d state = %v , want %v", i, j, sm.state, want.state)
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}
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if sm.term != want.term {
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t.Errorf("#%d.%d term = %v , want %v", i, j, sm.term, want.term)
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}
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if len(sm.log) != want.index {
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t.Errorf("#%d.%d index = %v , want %v", i, j, len(sm.log), want.index)
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}
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}
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}
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}
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func TestLogDiff(t *testing.T) {
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a := []Entry{{}, {Term: 1}, {Term: 2}}
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b := []Entry{{}, {Term: 1}, {Term: 2}}
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@ -349,8 +389,8 @@ func newNetwork(nodes ...Interface) *network {
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for i, n := range nodes {
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switch v := n.(type) {
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case nil:
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nt.ss[i] = newStateMachine(len(nodes), i, nt)
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case *stateMachine:
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nt.ss[i] = &nsm{*newStateMachine(len(nodes), i), nt}
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case *nsm:
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v.k = len(nodes)
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v.addr = i
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if v.next == nil {
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@ -375,7 +415,7 @@ func (nt network) Step(m Message) {
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func (nt network) logs() [][]Entry {
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ls := make([][]Entry, len(nt.ss))
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for i, node := range nt.ss {
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if sm, ok := node.(*stateMachine); ok {
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if sm, ok := node.(*nsm); ok {
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ls[i] = sm.log
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}
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}
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@ -462,3 +502,16 @@ type stepperFunc func(Message)
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func (f stepperFunc) Step(m Message) { f(m) }
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var nopStepper = stepperFunc(func(Message) {})
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type nsm struct {
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stateMachine
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next Interface
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}
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func (n *nsm) Step(m Message) {
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(&n.stateMachine).Step(m)
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ms := n.Msgs()
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for _, m := range ms {
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n.next.Step(m)
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}
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}
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