Example for Blog Post "Hexagonal Architecture: Structuring a project and the influence of granularity V2

driven_ports.go

##### the coarse-grained version #####

type ForStoringEvents interface {
  CreateEventStream(streamID lib.StreamID, event lib.Event) error
  AppendEventsToStream(
    streamID lib.StreamID,
	  expectedRevision uint64,
	  recordedEvents ...lib.Event,
  ) error
  ReadEventStream(streamID lib.StreamID) (lib.EventStream, error)
}

type ForReadingDeckSets interface {
  Read() (game.DeckSet, error)
}

type ForReadingProjections interface {
  ReadActivePlayersProjection() (game.ActivePlayersView, error)
  ReadLeaderboardProjection() (game.LeaderboardView, error)
}


##### the fine-grained version #####

type ForCreatingEventStreams interface {
  Create(streamID lib.StreamID, event lib.Event) error
}

type ForAppendingEventsToStreams interface {
  Append(
    streamID lib.StreamID,
	  expectedRevision uint64,
	  recordedEvents ...lib.Event,
  ) error
}

type ForReadingEventStreams interface {
  Read(streamID lib.StreamID) (lib.EventStream, error)
}

###

type ForReadingDeckSets interface {
  Read() (game.DeckSet, error)
}

###

type ForReadingActivePlayersProjections interface {
  Read() (game.ActivePlayersView, error)
}

type ForReadingLeaderboardProjections interface {
  Read() (game.LeaderboardView, error)
}