Safe Haskell	Safe-Inferred
Language	Haskell2010

Hercules.Agent.Producer

Synopsis

data Producer p r = Producer {
- producerQueueRead :: STM (Msg p r)
- producerThread :: ThreadId
}
data ProducerCancelled = ProducerCancelled
data Msg p r
- = Payload p
- | Exception SomeException
- | Close r
forkProducer :: forall m p r. MonadUnliftIO m => ((p -> m ()) -> m r) -> m (Producer p r)
cancel :: MonadIO m => Producer p r -> m ()
withProducer :: MonadUnliftIO m => ((p -> m ()) -> m r) -> (Producer p r -> m a) -> m a
listen :: MonadIO m => Producer p r -> (p -> m a) -> (r -> m a) -> STM (m a)
joinSTM :: MonadIO m => STM (m a) -> m a
data Syncing a
- = Syncable a
- | Syncer (Maybe SomeException -> STM ())
withSync :: (MonadUnliftIO m, Traversable t) => t (Syncing a) -> (t (Maybe a) -> m b) -> m b
withBoundedDelayBatchProducer :: MonadUnliftIO m => Int -> Int -> Producer p r -> (Producer [p] r -> m a) -> m a
syncer :: MonadIO m => (Syncing a -> m ()) -> m ()

Documentation

A thread producing zero or more payloads and a final value. Handles exception propagation.

Constructors

Producer
Fields producerQueueRead :: STM (Msg p r) producerThread :: ThreadId

Instances details

Functor (Producer p) Source #
Instance details Defined in Hercules.Agent.Producer Methods fmap :: (a -> b) -> Producer p a -> Producer p b # (<$) :: a -> Producer p b -> Producer p a #

Constructors

Instances details

Exception ProducerCancelled Source #
Instance details Defined in Hercules.Agent.Producer Methods toException :: ProducerCancelled -> SomeException # fromException :: SomeException -> Maybe ProducerCancelled # displayException :: ProducerCancelled -> String #
Show ProducerCancelled Source #
Instance details Defined in Hercules.Agent.Producer Methods showsPrec :: Int -> ProducerCancelled -> ShowS # show :: ProducerCancelled -> String # showList :: [ProducerCancelled] -> ShowS #

data Msg p r Source #

Constructors

Payload p	One of possibly many payloads from the producer
Exception SomeException	The producer stopped due to an exception
Close r	The producer was done and produced a final value

Instances details

Functor (Msg p) Source #
Instance details Defined in Hercules.Agent.Producer Methods fmap :: (a -> b) -> Msg p a -> Msg p b # (<$) :: a -> Msg p b -> Msg p a #

forkProducer :: forall m p r. MonadUnliftIO m => ((p -> m ()) -> m r) -> m (Producer p r) Source #

forkProducer f produces a computation that forks a thread for f, which receives a function for returning payloads p.

f may produce a final result value r when it is done.

Throws ProducerCancelled as an async exception to the producer thread. Blocks until exception is raised. See throwTo.

withProducer :: MonadUnliftIO m => ((p -> m ()) -> m r) -> (Producer p r -> m a) -> m a Source #

Perform an computation while withProducer takes care of forking and cleaning up.

withProducer (write -> write "a" >> write "b") $ producer -> consume producer

listen :: MonadIO m => Producer p r -> (p -> m a) -> (r -> m a) -> STM (m a) Source #

joinSTM :: MonadIO m => STM (m a) -> m a Source #

Constructors

Syncable a
Syncer (Maybe SomeException -> STM ())

Sends sync notifications after the whole computation succeeds (or fails) Note: not exception safe in the presence of pure exceptions.

Arguments

:: MonadUnliftIO m
=> Int	Max time before flushing in microseconds
-> Int	Max number of items in batch
-> Producer p r
-> (Producer [p] r -> m a)
-> m a

syncer :: MonadIO m => (Syncing a -> m ()) -> m () Source #