More refactoring

This commit is contained in:
Marto 2024-02-07 17:02:07 +02:00
parent 47e1e36294
commit fc50bf1271
6 changed files with 81 additions and 57 deletions

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@ -5,3 +5,19 @@ This project aims to develop an implementation of the Raft consensus protocol th
We plan to leverage the implementation to create a highly-efficient setup for operating a redundant set of Nimbus beacon nodes and/or validator clients that rely on BLS threshold signatures to achieve improved resilience and security. Further details can be found in our roadmap here:
https://github.com/status-im/nimbus-eth2/issues/3416
This project is heavily inspired by Raft implementation in ScyllaDB
https://github.com/scylladb/scylladb/tree/master/raft
# Design goals
The main goal is to separate implementation of the raft state machin from the other implementation details like (storage, rpc etc)
In order to achive this we want to keep the State machine absolutly deterministic every interaction the the world like
networking, logging, acquiring current time, random number generation, disc operation etc must happened trough the state machine interface.
It will ensure better testability and integrability.
# Run test
`./run_all_tests.sh`

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@ -10,6 +10,7 @@
import types
import log
import tracker
import state
import std/[times]
import std/sequtils
@ -47,8 +48,7 @@ type
term: RaftNodeTerm
case result: RaftRpcCode:
of Accepted: accepted: RaftRpcAppendReplayAccepted
of Rejected: rejected: RaftRpcAppendReplayRejected
of Rejected: rejected: RaftRpcAppendReplayRejected
RaftRpcVoteRequest* = object
currentTerm*: RaftNodeTerm
@ -60,15 +60,6 @@ type
currentTerm*: RaftNodeTerm
voteGranted*: bool
LeaderState* = object
tracker: RaftTracker
CandidateState* = object
votes: RaftVotes
FollowerState* = object
leader: RaftNodeId
RaftRpcMessage* = object
currentTerm*: RaftNodeTerm
sender*: RaftNodeId
@ -89,12 +80,6 @@ type
votedFor*: Option[RaftNodeId]
stateChange*: bool
RaftStateMachineState* = object
case state: RaftNodeState
of rnsFollower: follower : FollowerState
of rnsCandidate: candidate: CandidateState
of rnsLeader: leader: LeaderState
RaftStateMachine* = object
myId*: RaftNodeId
term*: RaftNodeTerm
@ -117,25 +102,6 @@ type
state*: RaftStateMachineState
func isLeader*(s: RaftStateMachineState): bool =
return s.state == RaftNodeState.rnsLeader
func isFollower*(s: RaftStateMachineState): bool =
return s.state == RaftNodeState.rnsFollower
func isCandidate*(s: RaftStateMachineState): bool =
return s.state == RaftNodeState.rnsCandidate
func leader*(s: var RaftStateMachineState): var LeaderState =
return s.leader
func follower*(s: var RaftStateMachineState): var FollowerState =
return s.follower
func candidate*(s: var RaftStateMachineState): var CandidateState =
return s.candidate
func leader*(sm: var RaftStateMachine): var LeaderState =
return sm.state.leader
@ -146,7 +112,7 @@ func candidate*(sm: var RaftStateMachine): var CandidateState =
return sm.state.candidate
func debug*(sm: var RaftStateMachine, log: string) =
sm.output.debugLogs.add("[" & $(sm.timeNow - sm.startTime).inMilliseconds & "ms] [" & (($sm.myId)[0..7]) & "...] [" & $sm.state.state & "]: " & log)
sm.output.debugLogs.add("[" & $(sm.timeNow - sm.startTime).inMilliseconds & "ms] [" & (($sm.myId)[0..7]) & "...] [" & $sm.state & "]: " & log)
proc resetElectionTimeout*(sm: var RaftStateMachine) =
# TODO actually pick random time
@ -157,7 +123,7 @@ proc initRaftStateMachine*(id: RaftnodeId, currentTerm: RaftNodeTerm, log: RaftL
sm.term = currentTerm
sm.log = log
sm.commitIndex = commitIndex
sm.state = RaftStateMachineState(state: RaftnodeState.rnsFollower)
sm.state = initFollower(RaftNodeId())
sm.config = config
sm.lastElectionTime = now
sm.timeNow = now
@ -168,7 +134,6 @@ proc initRaftStateMachine*(id: RaftnodeId, currentTerm: RaftNodeTerm, log: RaftL
sm.resetElectionTimeout()
return sm
func findFollowerProggressById(sm: var RaftStateMachine, id: RaftNodeId): Option[RaftFollowerProgressTracker] =
return sm.leader.tracker.find(id)
@ -247,7 +212,7 @@ func becomeFollower*(sm: var RaftStateMachine, leaderId: RaftNodeId) =
if sm.myId == leaderId:
sm.debug "Can't be follower of itself"
sm.output.stateChange = not sm.state.isFollower
sm.state = RaftStateMachineState(state: RaftNodeState.rnsFollower, follower: FollowerState(leader: leaderId))
sm.state = initFollower(leaderId)
if leaderId != RaftnodeId():
sm.pingLeader = false
# TODO: Update last election time
@ -258,9 +223,8 @@ func becomeLeader*(sm: var RaftStateMachine) =
return
sm.output.stateChange = true
sm.state = RaftStateMachineState(state: RaftnodeState.rnsLeader, leader: LeaderState())
sm.addEntry(Empty())
sm.leader.tracker = initTracker(sm.config, sm.log.lastIndex, sm.timeNow)
sm.state = initLeader(sm.config, sm.log.lastIndex, sm.timeNow)
sm.pingLeader = false
#TODO: Update last election time
return
@ -270,7 +234,7 @@ func becomeCandidate*(sm: var RaftStateMachine) =
if not sm.state.isCandidate:
sm.output.stateChange = true
sm.state = RaftStateMachineState(state: RaftnodeState.rnsCandidate, candidate: CandidateState(votes: initVotes(sm.config)))
sm.state = initCandidate(sm.config)
sm.lastElectionTime = sm.timeNow
# TODO: Add configuration change logic
@ -327,7 +291,6 @@ func tick*(sm: var RaftStateMachine, now: times.DateTime) =
sm.debug "Become candidate"
sm.becomeCandidate()
func poll*(sm: var RaftStateMachine): RaftStateMachineOutput =
# Should initiate replication if we have new entries
if sm.state.isLeader:
@ -338,7 +301,6 @@ func poll*(sm: var RaftStateMachine): RaftStateMachineOutput =
let output = sm.output
sm.output = RaftStateMachineOutput()
return output
func commit*(sm: var RaftStateMachine) =
@ -392,7 +354,6 @@ func advanceCommitIdx(sm: var RaftStateMachine, leaderIdx: RaftLogIndex) =
sm.commitIndex = newIdx
# TODO: signal the output for the update
func appendEntry*(sm: var RaftStateMachine, fromId: RaftNodeId, request: RaftRpcAppendRequest) =
if not sm.state.isFollower:
sm.debug "You can't append append request to the non follower"
@ -419,7 +380,6 @@ func requestVote*(sm: var RaftStateMachine, fromId: RaftNodeId, request: RaftRpc
let responce: RaftRpcVoteReplay = RaftRpcVoteReplay(currentTerm: sm.term, voteGranted: false)
sm.sendTo(fromId, responce)
func requestVoteReply*(sm: var RaftStateMachine, fromId: RaftNodeId, request: RaftRpcVoteReplay) =
if not sm.state.isCandidate:
sm.debug "Non candidate can't handle votes"

57
raft/state.nim Normal file
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@ -0,0 +1,57 @@
import types
import tracker
import std/[times]
type
RaftNodeState = enum
rnsFollower = 0, # Follower state
rnsCandidate = 1 # Candidate state
rnsLeader = 2 # Leader state
RaftStateMachineState* = object
case state: RaftNodeState
of rnsFollower: follower: FollowerState
of rnsCandidate: candidate: CandidateState
of rnsLeader: leader: LeaderState
LeaderState* = object
tracker*: RaftTracker
CandidateState* = object
votes*: RaftVotes
FollowerState* = object
leader*: RaftNodeId
func `$`*(s: RaftStateMachineState): string =
return $s.state
func initLeader*(cfg: RaftConfig, index: RaftLogIndex, now: times.DateTime): RaftStateMachineState =
var state = RaftStateMachineState(state: RaftnodeState.rnsLeader, leader: LeaderState())
state.leader.tracker = initTracker(cfg, index, now)
return state
func initFollower*(leaderId: RaftNodeId): RaftStateMachineState =
return RaftStateMachineState(state: RaftNodeState.rnsFollower, follower: FollowerState(leader: leaderId))
func initCandidate*(cfg: RaftConfig): RaftStateMachineState =
return RaftStateMachineState(state: RaftnodeState.rnsCandidate, candidate: CandidateState(votes: initVotes(cfg)))
func isLeader*(s: RaftStateMachineState): bool =
return s.state == RaftNodeState.rnsLeader
func isFollower*(s: RaftStateMachineState): bool =
return s.state == RaftNodeState.rnsFollower
func isCandidate*(s: RaftStateMachineState): bool =
return s.state == RaftNodeState.rnsCandidate
func leader*(s: var RaftStateMachineState): var LeaderState =
return s.leader
func follower*(s: var RaftStateMachineState): var FollowerState =
return s.follower
func candidate*(s: var RaftStateMachineState): var CandidateState =
return s.candidate

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@ -76,7 +76,6 @@ func tallyVote*(rv: var RaftVotes): RaftElectionResult =
# TODO: Add support for configuration
return rv.current.tallyVote()
func find*(ls: RaftTracker, id: RaftnodeId): Option[RaftFollowerProgressTracker] =
for follower in ls.progress:
if follower.id == id:

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@ -26,11 +26,6 @@ const
DefaultUUID* = initUUID(0, 0) # 00000000-0000-0000-0000-000000000000
type
RaftNodeState* = enum
rnsFollower = 0, # Follower state
rnsCandidate = 1 # Candidate state
rnsLeader = 2 # Leader state
RaftNodeId* = UUID # uuid4 uniquely identifying every Raft Node
RaftNodeTerm* = int # Raft Node Term Type
RaftLogIndex* = int # Raft Node Log Index Type

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@ -12,6 +12,7 @@ import ../raft/types
import ../raft/consensus_state_machine
import ../raft/log
import ../raft/tracker
import ../raft/state
import std/[times, sequtils]
import uuids
import tables
@ -57,16 +58,13 @@ proc advance(tc: var TestCluster, now: times.DateTime) =
#echo "rpc:" & $msg
tc.nodes[msg.receiver].advance(msg, now)
func getLeader(tc: TestCluster): Option[RaftStateMachine] =
for id, node in tc.nodes:
if node.state.isLeader:
return some(node)
return none(RaftStateMachine)
proc consensusstatemachineMain*() =
suite "Basic state machine tests":
test "create state machine":
@ -367,6 +365,5 @@ proc consensusstatemachineMain*() =
else:
check false
if isMainModule:
consensusstatemachineMain()