Eventful.ProcessManager

Documentation

data ProcessManager state event command

A ProcessManager manages interaction between aggregates. It works by listening to events on an event bus (see processManagerHandler) and applying events to its internal Projection. 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 event
• processManagerPendingCommands :: state -> [ProcessManagerCommand event command]
• processManagerPendingEvents :: state -> [ProcessManagerEvent 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

data ProcessManagerEvent event

This is an event paired with the UUID of the stream to which the event will be applied.

Constructors

ProcessManagerEvent

Fields

• processManagerEventProjectionId :: UUID
• processManagerEventEvent :: event

Instances

Eq event => Eq (ProcessManagerEvent event)

Methods

(==) :: ProcessManagerEvent event -> ProcessManagerEvent event -> Bool

(/=) :: ProcessManagerEvent event -> ProcessManagerEvent event -> Bool

Show event => Show (ProcessManagerEvent event)

Methods

showsPrec :: Int -> ProcessManagerEvent event -> ShowS

show :: ProcessManagerEvent event -> String

showList :: [ProcessManagerEvent event] -> ShowS

data ProcessManagerRouter state event command

A ProcessManagerRouter decides which process manager projection ID to use for a given event.

Constructors

ProcessManagerRouter

Fields

• processManagerRouterGetManagerId :: UUID -> event -> Maybe UUID
• processManagerRouterManager :: ProcessManager state event command

processManagerHandler :: Monad m => ProcessManagerRouter state event command -> EventStore event m -> UUID -> event -> m ()

This is an event handler for a ProcessManager that applies all events to the ProcessManagerRouter, and then applied any pending commands or events to the appropriate places.