Eventful.ProcessManager

Documentation

data ProcessManager state event command

A ProcessManager manages interaction between aggregates. It works by listening to events on an event bus and applying events to its internal Projection (see applyProcessManagerCommandsAndEvents). Then, pending commands and events are plucked off of that Projection and applied to the appropriate Aggregates or Projections in other streams.

Constructors

ProcessManager

Fields

• processManagerProjection :: Projection state (ProjectionEvent event)
• processManagerPendingCommands :: state -> [ProcessManagerCommand event command]
• processManagerPendingEvents :: state -> [ProjectionEvent event]

data ProcessManagerCommand event command

This is a command along with the UUID of the target Aggregate, and well as the Aggregate instance. Note that this uses an existential type to hide the state type parameter on the Aggregate.

Constructors

ProcessManagerCommand

Fields

• processManagerCommandAggregateId :: UUID
• processManagerCommandAggregate :: Aggregate state event command
• processManagerCommandCommand :: command

Instances

(Show command, Show event) => Show (ProcessManagerCommand event command)

Methods

showsPrec :: Int -> ProcessManagerCommand event command -> ShowS

show :: ProcessManagerCommand event command -> String

showList :: [ProcessManagerCommand event command] -> ShowS

applyProcessManagerCommandsAndEvents :: Monad m => ProcessManager state event command -> EventStore event m -> state -> m ()

Plucks the pending commands and events off of the process manager's state and applies them to the appropriate locations in the event store.