Safe Haskell	Safe-Inferred
Language	GHC2021

Hydra.Events

Description

This module defines the types and functions for creating EventSource and EventSink instances and is intended to be used as an extension point.

A single EventSource and zero or more EventSink handles are used by the main HydraNode handle to load and send out events.

See FileBased for an example implementation and FileBasedSpec for the corresponding test suite.

Custom implementations should be located under Hydra.Events to avoid conflicts.

Synopsis

type EventId = Word64
class HasEventId a where
- getEventId :: a -> EventId
newtype EventSource e m = EventSource {
- sourceEvents :: HasEventId e => ConduitT () e (ResourceT m) ()
}
getEvents :: (HasEventId e, MonadUnliftIO m) => EventSource e m -> m [e]
newtype EventSink e m = EventSink {
- putEvent :: HasEventId e => e -> m ()
}
putEventsToSinks :: (Monad m, HasEventId e) => [EventSink e m] -> [e] -> m ()

Documentation

Methods

Instances details

HasEventId Word64 Source #
Instance details Defined in Hydra.Events Methods getEventId :: Word64 -> EventId Source #
HasEventId (StateEvent tx) Source #
Instance details Defined in Hydra.HeadLogic.StateEvent Methods getEventId :: StateEvent tx -> EventId Source #

Constructors

EventSource
Fields sourceEvents :: HasEventId e => ConduitT () e (ResourceT m) () Stream all events from the event source.

getEvents :: (HasEventId e, MonadUnliftIO m) => EventSource e m -> m [e] Source #

Retrieve all events from the event source as a list.

Constructors

EventSink
Fields putEvent :: HasEventId e => e -> m () Send a single event to the event sink.

Put a list of events to a list of event sinks in a round-robin fashion.