| 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 {
- getEvents :: HasEventId e => m [e]
- newtype EventSink e m = EventSink {
- putEvent :: HasEventId e => e -> m ()
- putEventsToSinks :: (Monad m, HasEventId e) => [EventSink e m] -> [e] -> m ()
- data StateEvent tx = StateEvent {
- eventId :: EventId
- stateChanged :: StateChanged tx
- genStateEvent :: StateChanged tx -> Gen (StateEvent tx)
Documentation
class HasEventId a where Source #
Methods
getEventId :: a -> EventId Source #
Instances
| HasEventId (StateEvent tx) Source # | |
Defined in Hydra.Events Methods getEventId :: StateEvent tx -> EventId Source # | |
| HasEventId (EventId, a) Source # | |
Defined in Hydra.Events Methods getEventId :: (EventId, a) -> EventId Source # | |
newtype EventSource e m Source #
Constructors
| EventSource | |
Fields
| |
newtype EventSink e m Source #
Constructors
| EventSink | |
Fields
| |
putEventsToSinks :: (Monad m, HasEventId e) => [EventSink e m] -> [e] -> m () Source #
Put a list of events to a list of event sinks in a round-robin fashion.
State change events as used by Hydra.Node
data StateEvent tx Source #
A state change event with an event id that is the common entity to be
loaded from an EventSource and sent to EventSinks.
Constructors
| StateEvent | |
Fields
| |
Instances
genStateEvent :: StateChanged tx -> Gen (StateEvent tx) Source #