Then you’d have to encode the message type into the Actor ref, which would drastically decrease the value of something like the ActorRegistry. Also, with powerful mechanics like “become” (which is fundamental to the actor model) typing the messages is less valuable. Since Akka doesn’t leak memory when a message is not matched to the … Read more
Both stop and PoisonPill will terminate the actor and stop the message queue. They will cause the actor to cease processing messages, send a stop call to all its children, wait for them to terminate, then call its postStop hook. All further messages are sent to the dead letters mailbox. The difference is in which … Read more
You need a Flow: import akka.stream.OverflowStrategy.fail import akka.stream.scaladsl.Source import akka.stream.scaladsl.{Sink, Flow} case class Weather(zip : String, temp : Double, raining : Boolean) val weatherSource = Source.actorRef[Weather](Int.MaxValue, fail) val sunnySource = weatherSource.filter(!_.raining) val ref = Flow[Weather] .to(Sink.ignore) .runWith(sunnySource) ref ! Weather(“02139”, 32.0, true) Remember this is all experimental and may change!
If you consider a project like hseeberger/constructr and its issue 179, a native Akka solution should be based on akka/akka-management: This repository contains interfaces to inspect, interact and manage various Parts of Akka, primarily Akka Cluster. Future additions may extend these concepts to other parts of Akka. There is a demo for kubernetes.
Scheduler tasks should be placed only in Global class. Create two tasks, schedule only once first with initialDelay = 0 milliseconds. For the second task, you need to calculate seconds between current DateTime and next planned occurrence (ie. tomorrow at 8:00 o’clock) using common date/time classes, then set this difference as initialDelay and also set … Read more
There are three ways this can be achieved: 1. Post Materialization with SourceQueue You can use Source.queue that materializes the Flow into a SourceQueue: case class Weather(zipCode : String, temperature : Double, raining : Boolean) val bufferSize = 100 //if the buffer fills up then this strategy drops the oldest elements //upon the arrival of … Read more
It seems that your problem is bundling into a jar-with-dependencies, which causes problems with Akka, as described in the documentation: Warning Akka’s configuration approach relies heavily on the notion of every module/jar having its own reference.conf file, all of these will be discovered by the configuration and loaded. Unfortunately this also means that if you … Read more
You are making a very common mistake of “closing over mutable state”. The closure you pass to onComplete does not make a copy of this.sender, so when your onComplete gets called, you are sending the message to whatever this.sender happens to point to at that time, not what it pointed to when you created the … Read more
The optimal number of threads to use depends on several factors, but mostly the number of available processors and how cpu-intensive your tasks are. Java Concurrency in Practice proposes the following formal formula to estimate the optimal number of threads: N_threads = N_cpu * U_cpu * (1 + W / C) Where: N_threads is the … Read more
I have used it so far in two real projects very successfully. both are in the near real-time traffic information field (traffic as in cars on highways), distributed over several nodes, integrating messages between several parties, reliable backend systems. I’m not at liberty to give specifics on clients yet, when I do get the OK … Read more