raft

Documentation

Index

• Constants
• func DPrintf(format string, a ...interface{}) (n int, err error)
• type AppendEntryArgs
• type AppendEntryReply
• type ApplyMsg
• type LogEntry
• type Persister
  • func MakePersister() *Persister
  • func (ps *Persister) Copy() *Persister
  • func (ps *Persister) RaftStateSize() int
  • func (ps *Persister) ReadRaftState() []byte
  • func (ps *Persister) ReadSnapshot() []byte
  • func (ps *Persister) SaveRaftState(data []byte)
  • func (ps *Persister) SaveSnapshot(snapshot []byte)
• type Raft
  • func Make(peers []*labrpc.ClientEnd, me int, persister *Persister, applyCh chan ApplyMsg) *Raft
  • func (rf *Raft) AppendEntries(args AppendEntryArgs, reply *AppendEntryReply)
  • func (rf *Raft) GetState() (int, bool)
  • func (rf *Raft) Kill()
  • func (rf *Raft) RequestVote(args RequestVoteArgs, reply *RequestVoteReply)
  • func (rf *Raft) SendAppendEntriesToAllFollwer()
  • func (rf *Raft) SendAppendEntryToFollower(server int, args AppendEntryArgs, reply *AppendEntryReply) bool
  • func (rf *Raft) Start(command interface{}) (int, int, bool)
• type RequestVoteArgs
• type RequestVoteReply

Constants

const (
	STOPPED      = "stopped"
	INITIALIZED  = "initialized"
	FOLLOWER     = "follower"
	CANDIDATE    = "candidate"
	LEADER       = "leader"
	SNAPSHOTTING = "snapshotting"
)

const (
	HeartbeatCycle  = time.Millisecond * 50
	ElectionMinTime = 150
	ElectionMaxTime = 300
)

const Debug = 0

Debugging

Functions

func DPrintf

func DPrintf(format string, a ...interface{}) (n int, err error)

Types

type AppendEntryArgs

type AppendEntryArgs struct {
	Term         int
	Leader_id    int
	PrevLogIndex int
	PrevLogTerm  int
	Entries      []LogEntry
	LeaderCommit int
}

example AppendEntry RPC arguments structure.

type AppendEntryReply

type AppendEntryReply struct {
	Term        int
	Success     bool
	CommitIndex int
}

example AppendEntry RPC reply structure.

type ApplyMsg

type ApplyMsg struct {
	Index       int
	Command     interface{}
	UseSnapshot bool   // ignore for lab2; only used in lab3
	Snapshot    []byte // ignore for lab2; only used in lab3
}

as each Raft peer becomes aware that successive log entries are committed, the peer should send an ApplyMsg to the service (or tester) on the same server, via the applyCh passed to Make().

type LogEntry

type LogEntry struct {
	Command interface{}
	Term    int
}

log entry contains command for state machine, and term when entry was received by leader

type Persister

type Persister struct {
	// contains filtered or unexported fields
}

func MakePersister

func MakePersister() *Persister

func (*Persister) Copy

func (ps *Persister) Copy() *Persister

func (*Persister) RaftStateSize

func (ps *Persister) RaftStateSize() int

func (*Persister) ReadRaftState

func (ps *Persister) ReadRaftState() []byte

func (*Persister) ReadSnapshot

func (ps *Persister) ReadSnapshot() []byte

func (*Persister) SaveRaftState

func (ps *Persister) SaveRaftState(data []byte)

func (*Persister) SaveSnapshot

func (ps *Persister) SaveSnapshot(snapshot []byte)

type Raft

type Raft struct {
	// contains filtered or unexported fields
}

A Go object implementing a single Raft peer.

func Make

func Make(peers []*labrpc.ClientEnd, me int,
	persister *Persister, applyCh chan ApplyMsg) *Raft

the service or tester wants to create a Raft server. the ports of all the Raft servers (including this one) are in peers[]. this server's port is peers[me]. all the servers' peers[] arrays have the same order. persister is a place for this server to save its persistent state, and also initially holds the most recent saved state, if any. applyCh is a channel on which the tester or service expects Raft to send ApplyMsg messages. Make() must return quickly, so it should start goroutines for any long-running work.

func (*Raft) AppendEntries

func (rf *Raft) AppendEntries(args AppendEntryArgs, reply *AppendEntryReply)

append entries

func (*Raft) GetState

func (rf *Raft) GetState() (int, bool)

return currentTerm and whether this server believes it is the leader.

func (*Raft) Kill

func (rf *Raft) Kill()

the tester calls Kill() when a Raft instance won't be needed again. you are not required to do anything in Kill(), but it might be convenient to (for example) turn off debug output from this instance.

func (*Raft) RequestVote

func (rf *Raft) RequestVote(args RequestVoteArgs, reply *RequestVoteReply)

example RequestVote RPC handler.

func (*Raft) SendAppendEntriesToAllFollwer

func (rf *Raft) SendAppendEntriesToAllFollwer()

send appendetries to all follwer

func (*Raft) SendAppendEntryToFollower

func (rf *Raft) SendAppendEntryToFollower(server int, args AppendEntryArgs, reply *AppendEntryReply) bool

send appendetries to a follower

func (*Raft) Start

func (rf *Raft) Start(command interface{}) (int, int, bool)

the service using Raft (e.g. a k/v server) wants to start agreement on the next command to be appended to Raft's log. if this server isn't the leader, returns false. otherwise start the agreement and return immediately. there is no guarantee that this command will ever be committed to the Raft log, since the leader may fail or lose an election.

the first return value is the index that the command will appear at if it's ever committed. the second return value is the current term. the third return value is true if this server believes it is the leader.

type RequestVoteArgs

type RequestVoteArgs struct {
	// Your data here.
	Term         int // candidate's term
	CandidateId  int // candidate requesting vote
	LastLogIndex int // index of candidate's last log entry
	LastLogTerm  int // term of candidate's last log entry
}

example RequestVote RPC arguments structure.

type RequestVoteReply

type RequestVoteReply struct {
	// Your data here.
	Term        int  // currentTerm, for candidate to update itself
	VoteGranted bool // true means candidate received vote
}

example RequestVote RPC reply structure.