Raft.NodeState

Documentation

data Mode

Constructors

Follower

Candidate

Leader

Instances

Show Mode

Defined in Raft.NodeState

Methods

showsPrec :: Int -> Mode -> ShowS

show :: Mode -> String

showList :: [Mode] -> ShowS

data Transition (init :: Mode) (res :: Mode) where

All valid state transitions of a Raft node

Constructors

StartElection :: Transition Follower Candidate

HigherTermFoundFollower :: Transition Follower Follower

RestartElection :: Transition Candidate Candidate

DiscoverLeader :: Transition Candidate Follower

HigherTermFoundCandidate :: Transition Candidate Follower

BecomeLeader :: Transition Candidate Leader

SendHeartbeat :: Transition Leader Leader

DiscoverNewLeader :: Transition Leader Follower

HigherTermFoundLeader :: Transition Leader Follower

Noop :: Transition init init

Instances

Show (Transition init res)

Defined in Raft.NodeState

Methods

showsPrec :: Int -> Transition init res -> ShowS

show :: Transition init res -> String

showList :: [Transition init res] -> ShowS

data ResultState init where

Existential type hiding the result type of a transition

Constructors

ResultState :: Transition init res -> NodeState res -> ResultState init

Instances

Show (ResultState init)

Defined in Raft.NodeState

Methods

showsPrec :: Int -> ResultState init -> ShowS

show :: ResultState init -> String

showList :: [ResultState init] -> ShowS

followerResultState :: Transition init Follower -> FollowerState -> ResultState init

candidateResultState :: Transition init Candidate -> CandidateState -> ResultState init

leaderResultState :: Transition init Leader -> LeaderState -> ResultState init

data RaftNodeState where

Existential type hiding the internal node state

Constructors

RaftNodeState

Fields

• :: { unRaftNodeState :: NodeState s
•    } -> RaftNodeState

Instances

Show RaftNodeState

Defined in Raft.NodeState

Methods

showsPrec :: Int -> RaftNodeState -> ShowS

show :: RaftNodeState -> String

showList :: [RaftNodeState] -> ShowS

nodeMode :: RaftNodeState -> Mode

initRaftNodeState :: RaftNodeState

A node in Raft begins as a follower

data NodeState (a :: Mode) where

The volatile state of a Raft Node

Constructors

NodeFollowerState :: FollowerState -> NodeState Follower

NodeCandidateState :: CandidateState -> NodeState Candidate

NodeLeaderState :: LeaderState -> NodeState Leader

Instances

Show (NodeState v)

Defined in Raft.NodeState

Methods

showsPrec :: Int -> NodeState v -> ShowS

show :: NodeState v -> String

showList :: [NodeState v] -> ShowS

data CurrentLeader

Representation of the current leader in the cluster. The system is considered to be unavailable if there is no leader

Constructors

CurrentLeader LeaderId

NoLeader

Instances

Eq CurrentLeader

Defined in Raft.NodeState

Methods

(==) :: CurrentLeader -> CurrentLeader -> Bool

(/=) :: CurrentLeader -> CurrentLeader -> Bool

Show CurrentLeader

Defined in Raft.NodeState

Methods

showsPrec :: Int -> CurrentLeader -> ShowS

show :: CurrentLeader -> String

showList :: [CurrentLeader] -> ShowS

Generic CurrentLeader

Defined in Raft.NodeState

Associated Types

type Rep CurrentLeader :: Type -> Type

Methods

from :: CurrentLeader -> Rep CurrentLeader x

to :: Rep CurrentLeader x -> CurrentLeader

Serialize CurrentLeader

Defined in Raft.NodeState

Methods

put :: Putter CurrentLeader

get :: Get CurrentLeader

type Rep CurrentLeader

Defined in Raft.NodeState

type Rep CurrentLeader = D1 (MetaData "CurrentLeader" "Raft.NodeState" "libraft-0.1.1.0-8nwazCMBvi7EUIW9UIbZhF" False) (C1 (MetaCons "CurrentLeader" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 LeaderId)) :+: C1 (MetaCons "NoLeader" PrefixI False) (U1 :: Type -> Type))

data FollowerState

Constructors

FollowerState

Fields

• fsCurrentLeader :: CurrentLeader

  Id of the current leader

• fsCommitIndex :: Index

  Index of highest log entry known to be committed

• fsLastApplied :: Index

  Index of highest log entry applied to state machine

• fsLastLogEntryData :: (Index, Term)

  Index and term of the last log entry in the node's log

• fsTermAtAEPrevIndex :: Maybe Term

  The term of the log entry specified in and AppendEntriesRPC

Instances

Show FollowerState

Defined in Raft.NodeState

Methods

showsPrec :: Int -> FollowerState -> ShowS

show :: FollowerState -> String

showList :: [FollowerState] -> ShowS

data CandidateState

Constructors

CandidateState

Fields

• csCommitIndex :: Index

  Index of highest log entry known to be committed

• csLastApplied :: Index

  Index of highest log entry applied to state machine

• csVotes :: NodeIds

  Votes from other nodes in the raft network

• csLastLogEntryData :: (Index, Term)

  Index and term of the last log entry in the node's log

Instances

Show CandidateState

Defined in Raft.NodeState

Methods

showsPrec :: Int -> CandidateState -> ShowS

show :: CandidateState -> String

showList :: [CandidateState] -> ShowS

type ClientReadReqs = Map Int (ClientId, Int)

data LeaderState

Constructors

LeaderState

Fields

• lsCommitIndex :: Index

  Index of highest log entry known to be committed

• lsLastApplied :: Index

  Index of highest log entry applied to state machine

• lsNextIndex :: Map NodeId Index

  For each server, index of the next log entry to send to that server

• lsMatchIndex :: Map NodeId Index

  For each server, index of highest log entry known to be replicated on server

• lsLastLogEntryData :: (Index, Term, Maybe EntryIssuer)

  Index, term, and client id of the last log entry in the node's log. The only time `Maybe ClientId` will be Nothing is at the initial term.

• lsReadReqsHandled :: Int

  Number of read requests handled this term

• lsReadRequest :: ClientReadReqs

  The number of successful responses received regarding a specific read request heartbeat.

Instances

Show LeaderState

Defined in Raft.NodeState

Methods

showsPrec :: Int -> LeaderState -> ShowS

show :: LeaderState -> String

showList :: [LeaderState] -> ShowS

setLastLogEntryData :: NodeState ns -> Entries v -> NodeState ns

Update the last log entry in the node's log

getLastLogEntryData :: NodeState ns -> (Index, Term)

Get the last applied index and the commit index of the last log entry in the node's log

getLastAppliedAndCommitIndex :: NodeState ns -> (Index, Index)

Get the index of highest log entry applied to state machine and the index of highest log entry known to be committed

isFollower :: NodeState s -> Bool

Check if node is in a follower state

isCandidate :: NodeState s -> Bool

Check if node is in a candidate state

isLeader :: NodeState s -> Bool

Check if node is in a leader state