A filter wraps the messages a node receives

entered in registration order and unwound in reverse · a Spot handler is not wrapped

A filter wraps the messages a node receives entered in registration order and unwound in reverse · a Spot handler is not wrapped received message · channel · node direct · fanout · Architecture component received message channel · node direct · fanout first filter · registered first · what the filter wraps first filter registered first second filter · registered later · what the filter wraps second filter registered later handler · registered by the node · what the filter wraps handler registered by the node Spot handler · registered by the Spot · Architecture component Spot handler registered by the Spot next next unwinds in reverse does not pass a filter what the filter wraps

Registration order is execution order

  • • Filters pass in front of the handler in registration order, and unwind in reverse once next returns. Each filter calls next at most once.
  • • What a filter wraps is the messages a node receives. Handlers owned by a Spot or an Actor, subscriptions a Spot registers, and STREAM session handlers do not pass through it.