happstack-state-0.5.1: Event-based distributed state.

Happstack.State

Contents

Synopsis

ACID monad

data Ev m t Source

Monad for ACID event handlers.

type AnyEv a = forall t. (Monad (t STM), MonadTrans t) => Ev (t STM) aSource

ACID computations that work with any state and event types.

data TxControl Source

query :: (MonadIO m, QueryEvent ev res) => ev -> m resSource

Emit a state query and wait for the result.

update :: (MonadIO m, UpdateEvent ev res) => ev -> m resSource

Schedule an update and wait for it to complete. When this function returns, you're guaranteed the update will be persistent.

type Update state = Ev (StateT state STM)Source

type Query state = Ev (ReaderT state STM)Source

Types

type TxId = Int64Source

type EpochMilli = Int64Source

data Saver Source

Constructors

NullSaver

A saver that discards all output

FileSaver String

A saver that operates on files. The parameter is the prefix for the files.

Queue Saver

Enable queueing.

Memory (MVar Store) 

Misc utilities

module Happstack.State.Monad

getEventId :: Integral txId => AnyEv txIdSource

getTime :: Integral epochTime => AnyEv epochTimeSource

getEventClockTime :: AnyEv ClockTimeSource

getEventStream :: IO (IO EventItem)Source

data EventItem Source

Constructors

EventItem 

Fields

eventContext :: TxContext
 
eventData :: Dynamic
 

module Happstack.State.Util

Serialization

module Happstack.Data.Serialize

module Happstack.Data.SerializeTH

module Happstack.State.Control

module Happstack.State.ComponentTH

module Happstack.State.ComponentSystem

runTxSystem :: (Methods st, Component st) => Saver -> Proxy st -> IO (MVar TxControl)Source

Run the MACID system without multimaster support and with the given Saver.

createCheckpoint :: MVar TxControl -> IO ()Source

shutdownSystem :: MVar TxControl -> IO ()Source

Shuts down a transaction system

Unsafe things

unsafeIOToEv :: IO a -> AnyEv aSource