raft

Documentation

Index

• Constants
• Variables
• func Color(colorString string) func(...interface{}) string
• func Dlog(format string, a ...interface{}) (n int, err error)
• func MicroSecondNow() int64
• type AppendEntryArgs
• type AppendEntryReply
• type ApplyMsg
• type Entry
• type ErrNotFound
  • func (e *ErrNotFound) Error() string
• 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(state []byte)
  • func (ps *Persister) SaveSnapShot(data []byte)
  • func (ps *Persister) SaveStateAndSnapshot(state []byte, snapshot []byte)
  • func (ps *Persister) SnapshotSize() int
• type Raft
  • func Make(peers []*labrpc.ClientEnd, me int, persister *Persister, applyCh chan ApplyMsg) *Raft
  • func (rf *Raft) AppendEntry(args *AppendEntryArgs, reply *AppendEntryReply)
  • func (rf *Raft) DropBeforeIndex(index int, justCheck bool, snapshot []byte) int
  • func (rf *Raft) GetState() (int, bool)
  • func (rf *Raft) GetState2() (int, int, bool)
  • func (rf *Raft) InstallSnapshot(args *AppendEntryArgs, reply *AppendEntryReply)
  • func (rf *Raft) Kill()
  • func (rf *Raft) Killed() bool
  • func (rf *Raft) MaySaveSnapShot(snapShot []byte, index, term int) int
  • func (rf *Raft) ReadSnapShot() []byte
  • func (rf *Raft) RequestVote(args *RequestVoteArgs, reply *RequestVoteReply)
  • func (rf *Raft) SateSize() int
  • func (rf *Raft) SaveSnapShot(data []byte)
  • func (rf *Raft) Start(command interface{}) (int, int, bool)
• type RequestVoteArgs
• type RequestVoteReply

Constants

const (
	STATE_LEADER     = iota
	STATE_CANDIDATER = iota
	STATE_FOLLOWER   = iota
)

const (
	VOTED_FOR_NULL     = -1
	INIT_APPMSG_TERM   = -2
	INIT_APPMSG_INDEX  = -2
	INVALID_INDEX_HINT = -2
	NO_LEADER          = -1
	INVALID_TERM       = -2
)

const (
	NOT_FOUND_LEFT             = -1
	DROP_RAFT_STATE_FAILED     = -1
	NO_NEED_TO_DROP_RAFT_STATE = -2
)

const Debug = 0

Variables

var (
	NANO_TO_MILLI = int64(1000000)

	Black   = Color("\033[1;30m%s\033[0m")
	Red     = Color("\033[1;31m%s\033[0m")
	Blue    = Color("\033[0;31m%s\033[0m")
	Green   = Color("\033[1;32m%s\033[0m")
	Yellow  = Color("\033[1;33m%s\033[0m")
	Purple  = Color("\033[1;34m%s\033[0m")
	Magenta = Color("\033[1;35m%s\033[0m")
	Teal    = Color("\033[1;36m%s\033[0m")
	White   = Color("\033[1;37m%s\033[0m")
)

Functions

func Color

func Color(colorString string) func(...interface{}) string

func Dlog

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

func MicroSecondNow

func MicroSecondNow() int64

Types

type AppendEntryArgs

type AppendEntryArgs struct {
	Term                int
	LeaderId            int
	PrevLogIndex        int
	PrevLogTerm         int
	Entries             []Entry
	CommitIndex         int
	SnapShot            []byte
	WillInstallSnapShot bool
}

appendEntry RPC arguments structure.

type AppendEntryReply

type AppendEntryReply struct {
	Term      int // 为什么还需要 update it self
	Success   bool
	IndexHint int
}

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
	LatestIndex int
	LatestTerm  int
}

type Entry

type Entry struct {
	Command  interface{}
	Term     int
	Index    int
	SnapShot []byte
}

type ErrNotFound

type ErrNotFound struct {
	Msg string
}

func (*ErrNotFound) Error

func (e *ErrNotFound) Error() string

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(state []byte)

func (*Persister) SaveSnapShot

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

func (*Persister) SaveStateAndSnapshot

func (ps *Persister) SaveStateAndSnapshot(state []byte, snapshot []byte)

Save both Raft state and K/V snapshot as a single atomic action, to help avoid them getting out of sync.

func (*Persister) SnapshotSize

func (ps *Persister) SnapshotSize() int

type Raft

type Raft struct {
	LeaderId int
	Term     int
	State    int // Leader, Candidator, Follower

	VotedFor int

	MinElectTime      int
	MaxElectTime      int
	HeartBeatInterval time.Duration
	// 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) AppendEntry

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

func (*Raft) DropBeforeIndex

func (rf *Raft) DropBeforeIndex(index int, justCheck bool, snapshot []byte) int

raft.log 至少保存一条记录!

func (*Raft) GetState

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

believes it is the leader.

func (*Raft) GetState2

func (rf *Raft) GetState2() (int, int, bool)

believes it is the leader.

func (*Raft) InstallSnapshot

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

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) Killed

func (rf *Raft) Killed() bool

func (*Raft) MaySaveSnapShot

func (rf *Raft) MaySaveSnapShot(snapShot []byte, index, term int) int

func (*Raft) ReadSnapShot

func (rf *Raft) ReadSnapShot() []byte

func (*Raft) RequestVote

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

example RequestVote RPC handler.

func (*Raft) SateSize

func (rf *Raft) SateSize() int

func (*Raft) SaveSnapShot

func (rf *Raft) SaveSnapShot(data []byte)

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 {
	Term         int
	CandidateId  int
	LastLogIndex int
	LastLogTerm  int
}

type RequestVoteReply

type RequestVoteReply struct {
	Term        int
	VoteGranted bool
}

example RequestVote RPC reply structure. field names must start with capital letters!