Safe Haskell	None
Language	Haskell2010

Raft.StateMachine

Synopsis

class RaftStateMachinePure sm v | sm -> v where
- data RaftStateMachinePureError sm v
- type RaftStateMachinePureCtx sm v = ctx | ctx -> sm v
- rsmTransition :: RaftStateMachinePureCtx sm v -> sm -> v -> Either (RaftStateMachinePureError sm v) sm
class (Monad m, RaftStateMachinePure sm v) => RaftStateMachine m sm v where
- validateCmd :: v -> m (Either (RaftStateMachinePureError sm v) ())
- preprocessCmd :: v -> m v
- askRaftStateMachinePureCtx :: m (RaftStateMachinePureCtx sm v)
data EntryValidation
- = NoMonadicValidation
- | MonadicValidation
applyLogEntry :: RaftStateMachine m sm v => EntryValidation -> sm -> Entry v -> m (Either (RaftStateMachinePureError sm v) sm)
applyLogCmd :: forall sm cmd m. RaftStateMachine m sm cmd => EntryValidation -> sm -> cmd -> m (Either (RaftStateMachinePureError sm cmd) sm)

Documentation

class RaftStateMachinePure sm v | sm -> v where Source #

Interface to handle commands in the underlying state machine. Functional dependency permitting only a single state machine command to be defined to update the state machine.

Associated Types

data RaftStateMachinePureError sm v Source #

type RaftStateMachinePureCtx sm v = ctx | ctx -> sm v Source #

Methods

rsmTransition :: RaftStateMachinePureCtx sm v -> sm -> v -> Either (RaftStateMachinePureError sm v) sm Source #

class (Monad m, RaftStateMachinePure sm v) => RaftStateMachine m sm v where Source #

Minimal complete definition

validateCmd, askRaftStateMachinePureCtx

Methods

validateCmd :: v -> m (Either (RaftStateMachinePureError sm v) ()) Source #

Expensive validation using global state not cacheable in RaftStateMachinePureCtx

preprocessCmd :: v -> m v Source #

Some state machines need the leader to preprocess commands issued by client; e.g. attaching a timestamp before creating the log entry

askRaftStateMachinePureCtx :: m (RaftStateMachinePureCtx sm v) Source #

Query the RaftStateMachinePureCtx value from the monadic context

preprocessCmd :: v -> m v Source #

Some state machines need the leader to preprocess commands issued by client; e.g. attaching a timestamp before creating the log entry

Instances

RaftStateMachine m sm v => RaftStateMachine (RaftPostgresT m) sm v Source #
Instance details Defined in Raft.Log.PostgreSQL Methods validateCmd :: v -> RaftPostgresT m (Either (RaftStateMachinePureError sm v) ()) Source # preprocessCmd :: v -> RaftPostgresT m v Source # askRaftStateMachinePureCtx :: RaftPostgresT m (RaftStateMachinePureCtx sm v) Source #
RaftStateMachine m sm v => RaftStateMachine (RaftPersistFileStoreT m) sm v Source #
Instance details Defined in Examples.Raft.FileStore.Persistent Methods validateCmd :: v -> RaftPersistFileStoreT m (Either (RaftStateMachinePureError sm v) ()) Source # preprocessCmd :: v -> RaftPersistFileStoreT m v Source # askRaftStateMachinePureCtx :: RaftPersistFileStoreT m (RaftStateMachinePureCtx sm v) Source #
RaftStateMachine m sm v => RaftStateMachine (RaftLogFileStoreT m) sm v Source #
Instance details Defined in Examples.Raft.FileStore.Log Methods validateCmd :: v -> RaftLogFileStoreT m (Either (RaftStateMachinePureError sm v) ()) Source # preprocessCmd :: v -> RaftLogFileStoreT m v Source # askRaftStateMachinePureCtx :: RaftLogFileStoreT m (RaftStateMachinePureCtx sm v) Source #
RaftStateMachine m sm v => RaftStateMachine (RaftSocketT sm v m) sm v Source #
Instance details Defined in Examples.Raft.Socket.Node Methods validateCmd :: v -> RaftSocketT sm v m (Either (RaftStateMachinePureError sm v) ()) Source # preprocessCmd :: v -> RaftSocketT sm v m v Source # askRaftStateMachinePureCtx :: RaftSocketT sm v m (RaftStateMachinePureCtx sm v) Source #

data EntryValidation Source #

Constructors

NoMonadicValidation
MonadicValidation

applyLogEntry :: RaftStateMachine m sm v => EntryValidation -> sm -> Entry v -> m (Either (RaftStateMachinePureError sm v) sm) Source #

Apply a log entry to the supplied state machine, allowing the user to specify whether or not to monadically validate the command in addition to the pure validation logic.

This function first unwraps the log entry to see if it is a no-op or contains an actual state machine command to apply.

applyLogCmd :: forall sm cmd m. RaftStateMachine m sm cmd => EntryValidation -> sm -> cmd -> m (Either (RaftStateMachinePureError sm cmd) sm) Source #

Apply a state machine command to the supplied state machine, allowing the user to specify whether or not to monadically validate the command in addition to the pure validation logic.