99 lines
3.0 KiB
Nim
99 lines
3.0 KiB
Nim
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import types
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import std/sequtils
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import std/[times]
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type
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RaftElectionResult* = enum
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Unknown = 0,
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Won = 1,
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Lost = 2
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RaftElectionTracker* = object
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all: seq[RaftNodeId]
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responded: seq[RaftNodeId]
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granted: int
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RaftVotes* = object
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voters*: seq[RaftNodeId]
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current: RaftElectionTracker
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RaftFollowerProgress = seq[RaftFollowerProgressTracker]
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RaftTracker* = object
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progress*: RaftFollowerProgress
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current: seq[RaftNodeId]
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RaftFollowerProgressTracker* = ref object
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id*: RaftNodeId
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nextIndex*: RaftLogIndex
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# Index of the highest log entry known to be replicated to this server.
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matchIndex*: RaftLogIndex
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commitIndex*: RaftLogIndex
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replayedIndex: RaftLogIndex
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lastMessageAt*: times.DateTime
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func initElectionTracker*(nodes: seq[RaftNodeId]): RaftElectionTracker =
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var r = RaftElectionTracker()
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r.all = nodes
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r.granted = 0
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return r
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func registerVote*(ret: var RaftElectionTracker, nodeId: RaftNodeId, granted: bool): bool =
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if not ret.all.contains nodeId:
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return false
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if not ret.responded.contains nodeId:
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ret.responded.add(nodeId)
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if granted:
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ret.granted += 1
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return true
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func tallyVote*(ret: var RaftElectionTracker): RaftElectionResult =
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let quorym = int(len(ret.all) / 2) + 1
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if ret.granted >= quorym:
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return RaftElectionResult.Won
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let unkown = len(ret.all) - len(ret.responded)
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if ret.granted + unkown >= quorym:
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return RaftElectionResult.Unknown
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else:
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return RaftElectionResult.Lost
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func initVotes*(nodes: seq[RaftNodeId]): RaftVotes =
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var r = RaftVotes(voters: nodes, current: initElectionTracker(nodes))
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return r
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func initVotes*(config: RaftConfig): RaftVotes =
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var r = RaftVotes(voters: config.currentSet, current: initElectionTracker(config.currentSet))
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return r
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func registerVote*(rv: var RaftVotes, nodeId: RaftNodeId, granted: bool): bool =
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# TODO: Add support for configuration
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return rv.current.registerVote(nodeId, granted)
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func tallyVote*(rv: var RaftVotes): RaftElectionResult =
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# TODO: Add support for configuration
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return rv.current.tallyVote()
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func find*(ls: RaftTracker, id: RaftnodeId): Option[RaftFollowerProgressTracker] =
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for follower in ls.progress:
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if follower.id == id:
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return some(follower)
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return none(RaftFollowerProgressTracker)
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func initFollowerProgressTracker*(follower: RaftNodeId, nextIndex: RaftLogIndex, now: times.DateTime): RaftFollowerProgressTracker =
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return RaftFollowerProgressTracker(id: follower, nextIndex: nextIndex, matchIndex: 0, commitIndex: 0, replayedIndex: 0, lastMessageAt: now)
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func initTracker*(config: RaftConfig, nextIndex: RaftLogIndex, now: times.DateTime): RaftTracker =
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var tracker = RaftTracker()
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for node in config.currentSet:
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tracker.progress.add(initFollowerProgressTracker(node, nextIndex, now))
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tracker.current.add(node)
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return tracker
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func accepted*(fpt: var RaftFollowerProgressTracker, index: RaftLogIndex)=
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fpt.matchIndex = max(fpt.matchIndex, index)
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fpt.nextIndex = max(fpt.nextIndex, index)
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