I would like to chain http request using akka-http-client as Stream. Each http request in a chain depends on a success/response of a previous requests and uses it to construct a new request. If a r...

I am working with a data publisher from a java library that I do not control. The publisher library uses a typical callback setup; somewhere in the library code (the library is java but I will desc...

I'm currently trying to dynamically create Akka Stream graph definitions at runtime. The idea being that users will be able to define flows interactively and attach them to existing/running Broadca...

I am currently working with Akka Stream Kafka to interact with kafka and I was wonderings what were the differences with Kafka Streams. I know that the Akka based approach implements the reactive ...

I have an external (that is, I cannot change it) Java API which looks like this: public interface Sender { void send(Event e); } I need to implement a Sender which accepts each event, transform...

I've been trying to set-up some instrumentation for Akka streams. Got it working, but, even though I named all my Flows that are part of the streams, I still get this sort of names in the metrics: ...

I'm new to akka-streams and not sure how to approach this problem. I have 3 source streams are sorted by a sequence ID. I want to group the values together which have the same ID. Values in each s...

I use Akka Stream on Scala. I'd like to set a scheduler which runs on every 24:00. I tried to search for it. But I could't find what I want to do. Could you tell me how to write code?

I have an Akka Streams Source which I want to split into two sources according to a predicate. E.g. having a source (types are simplified intentionally): val source: Source[Either[Throwable, Stri...

I'm trying to create a simple Proxy for Websocket connections using Play and akka streams. The traffic flow is like this: (Client) request -> -> request (Server) Proxy (Client) response &...

I have a WebSocket server I need to send and receive messages to it over the established WebSocket connection as Akka client-side WebSocket does not provide us the conventional websocket.send() fea...

In Slick's documentation examples for using Reactive Streams are presented just for reading data as a means of a DatabasePublisher. But what happens when you want to use your database as a Sink and...

Why is the exception in import akka.actor.ActorSystem import akka.stream.ActorMaterializer import akka.stream.scaladsl.Source object TestExceptionHandling { def main(args: Array[String]): Unit =...

I need to call an upstream service (Azure Blob Service) to push data to an OutputStream, which then i need to turn around and push it back to the client, thru akka. Without akka (and just servlet c...

While exploring Akka streams, I also came across Apache Flink which stream processing engine. Akka streams implements reactive streams and supports back pressure. So if I have to make decision be...

The code below does not compile, it says that ActorMaterializer is missing an implicit ActorRefFactory. How should I provide one? val guardian: Behavior[Done] = Behaviors.setup(_ => { Behavior...

I am trying to figure out how to work with slick streaming. I use slick 3.0.0 with postgres driver The situation is following: server have to give client sequences of data split into chunks limite...

Since 2.6 i get deprecation warning on this line: import akka.stream.ActorMaterializer implicit val actorMaterializer = ActorMaterializer() Warning: method apply in object ActorMaterializer...

I have a question. I have Akka HTTP Server and using Akka HTTP Client. The Client does a lot of external calls basically with Http.singleRequest(). This takes a lot of time and sometimes User clo...

I have example code to generate an unbound source and working with it: object Main { def main(args : Array[String]): Unit = { implicit val system = ActorSystem("Sys") import system.dispatcher...

I would like to create a Source and later push elements on it, like in: val src = ... // create the Source here // and then, do something like this pushElement(x1, src) pushElement(x2, src) What...

I want to read multiple big files using Akka Streams to process each line. Imagine that each key consists of an (identifier -> value). If a new identifier is found, I want to save it and its val...

Is there an idiomatic way of handling Akka stream's Source first element in a special way? What I have now is: var firstHandled = false source.map { elem => if(!firstHandled) { //handle spe...

I have a use case where I want to send a message to an external system but the flow that sends this message takes and returns a type I cant use downstream. This is a great use case for the pass thr...

We are trying to use Akka Streams with Alpakka Kafka to consume a stream of events in a service. For handling event processing errors we are using Kafka autocommit and more than one queue. For exam...