docs/cc.otavia/cc.otavia.core/cc.otavia.core.interceptor

cc.otavia.core.interceptor

Members list

Type members

Classlikes

Base class for interceptor actors that wrap a target Address and forward messages through a chain.

Interceptors are normal actors that use the standard Stack coroutine pattern (override resumeAsk / resumeNotice with state matching). The forwardAsk helper encapsulates the common pattern of forwarding to the next address and suspending until the reply arrives.

Concept mapping (for understanding, not API):

// Industry concept        -> Otavia equivalent
// chain.proceed()         -> forwardAsk(stack)
// preHandle return false  -> stack.return(rejectReply) without calling forwardAsk
// postHandle              -> match FutureState with ForwardStateId, process reply, then stack.return
// onion model             -> Stack StartState -> suspend -> FutureState naturally implements this

Example - logging interceptor:

class LoggingInterceptor(val next: Address[HttpRequest]) extends InterceptorActor[HttpRequest] {
  override protected def resumeAsk(stack: AskStack[HttpRequest & Ask[? <: Reply]]): StackYield = {
    stack.state match {
      case _: StartState =>
        stack.attach(System.nanoTime())
        forwardAsk(stack)
      case state: FutureState[_] if state.id == ForwardStateId =>
        val elapsed = (System.nanoTime() - stack.attach[Long]) / 1_000_000
        logger.info(s"${stack.ask.method} ${stack.ask.path} -> ${elapsed}ms")
        stack.`return`(state.future.getNow.asInstanceOf)
    }
  }
}

Type parameters

M: the message type this interceptor handles, must match the target actor's type

Attributes

Supertypes: class StateActor[M]

trait Actor[M]

class Object

trait Matchable

class Any

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