Data dodania Pytanie
2017-11-18 16:11 How to compose two Flows side-by-side? »
Is there an Akka streams combinator for doing the following (or something to that effect)? (Let's call it and for now.) (flow1: Flow[I, O, Mat]).and[...
(1) odpowiedzi
2017-11-03 22:11 Akka stream stays idle instead of throwing exception »
I am new to Akka/Scala and am trying to debug the code below. When the resultSetParser has an exception, it does not throw it. Instead the service tha...
(1) odpowiedzi
2017-10-12 17:10 Wait for a Scala Future to complete and continue with the next one »
I have a list of 500,000 elements and a queue with 20 consumers. The messages are processed at different speeds (1, 15, 30, 60 seconds; 3, 50 min; 3, ...
(2) odpowiedzi
2017-09-26 22:09 akka-stream + akka-http lifecycle »
TLDR: is it better to materialize a stream per request (i.e. use short-lived streams) or to use a single stream materialization across requests, when ...
(1) odpowiedzi
2017-09-04 17:09 Scala : File reading to Build an external Merge Sort »
I want to implement an external Merge Sort in Scala. It is used to sort huge files which can not fit in the main memory in their entirety. Details ca...
(1) odpowiedzi
2017-09-01 03:09 Akka Streams Inlets and Outlets match »
Here is the simplest graph using a Partition and Merge that I could come up with, but when run it gives the following error: requirement failed: The i...
(1) odpowiedzi
2017-08-02 20:08 Akka streams — filtering by the number of elements in stream »
I'm writing an app in Scala and I'm using Akka streams. At one point, I need to filter out streams that have less than N elements, with N given. So, ...
(2) odpowiedzi
2017-07-24 15:07 SHA256 of data stream »
I am having a use case where i am downloading the file from URL using GET request. Is it possible to calculate SHA256 of file stream without saving to...
(3) odpowiedzi
2017-06-26 15:06 Monadic short-circuiting in Akka Streams »
I'd like to chain a series of Flow's of the form a -> Try[b], where each successive stage handles the Success case of the previous, and the Sink at...
(1) odpowiedzi
2017-06-25 11:06 How do I preserve materialized value in custom Sink? »
Could you please tell me how to preserve materialized Future[Int] in example like this ? val test: Sink[Int, NotUsed] = MergeHub.source[Int].groupe...
(1) odpowiedzi
2017-06-20 16:06 Akka stream sort by id in java »
I need to sort my akka stream list by id in java I have list of objects in akka source: SystemCodeTracking{id=9, EntityName='table3'} SystemCodeTrack...
(1) odpowiedzi
2017-06-11 12:06 Akka Streams: validation of elements being streamed »
I'm new to Akka Streams and I'm wondering how to implement some kind of mid-stream validation. Example: FileIO .fromPath(file) .via(Framing.delim...
(3) odpowiedzi
2017-05-28 09:05 Why is the stream stopped immediately and how to prevent it »
In a simple test, I am expecting the flow to generate and print numbers for one second. I want to test stream operations dealing with backpressure and...
(1) odpowiedzi
2017-05-17 16:05 Why doesn't Keep.None affect the Akka stream execution result? »
I have a simple test code for Akka Streams (written in F# but Scala version isn't match different): var source = Source.From(Enumerable.Range(1, ...
(2) odpowiedzi
2017-05-17 07:05 How to clean up substreams in continuous Akka streams »
Given I have a very long running stream of events flowing through something as show below. When a long time has passed there will be lots of sub strea...
(1) odpowiedzi
2017-04-26 18:04 Dynamically creating Akka Stream Flows at Runtime »
I'm currently trying to dynamically create Akka Stream graph definitions at runtime. The idea being that users will be able to define flows interactiv...
(0) odpowiedzi
2017-04-24 15:04 Akka Stream, Source from function? »
I want to have a Source that evaluates a function at given intervals and emits its output. As a workaround, I can do it with a Source.queue + offer, b...
(2) odpowiedzi
2017-03-30 15:03 Akka Stream connect to multiple sinks »
I have implemented a custom component in akka stream which takes elements as input, groups and merges them based on a key and sends them out through o...
(2) odpowiedzi
2017-03-28 14:03 akka-http and JsonEntityStreamingSupport »
I'm currently doing some experiment with akka and its persistency stack, wrapped with akka-http stack. Note: For persistency, i'm using non-official ...
(1) odpowiedzi
2017-03-25 08:03 Is connection pooling in akka-http using the source queue Implementation thread safe? »
Refering to the following implementation mentioned in: http://doc.akka.io/docs/akka-http/10.0.5/scala/http/client-side/host-level.html val poolClie...
(2) odpowiedzi
2017-03-17 17:03 Can the subflows of groupBy depend on the keys they were generated from ? »
I have a flow with data associated to users. I also have a state for each user, that I can get asynchronously from DB. I want to separate my flow wit...
(0) odpowiedzi
2017-03-05 08:03 akka stream: how to reconnect TCP after disconnected »
I have a simple balancer that dispatch jobs to several external worker processes via TCP: val sinkBalance = Sink.fromGraph(GraphDSL.create() { implic...
(0) odpowiedzi
2017-02-24 17:02 akka-http: send element to akka sink from http route »
How can I send elements/messages to an Akka Sink from an Akka HTTP route? My HTTP route still needs to return a normal HTTP response. I imagine this ...
(2) odpowiedzi
2017-02-07 18:02 Composing BodyParser in Play 2.5 »
Given a function with this signature: def parser[A](otherParser: BodyParser[A]): BodyParser[A] How can I write the function in such a way that the ...
(1) odpowiedzi
2017-01-31 13:01 FTP does not work from mesos docker container »
I have scala application with akka steams. So the flow of my application is like this: 1. Check if file exists on FTP - I'm doing it with the org.apa...
(1) odpowiedzi
2016-12-30 15:12 Akka flow for multiple http requests »
In a project of mine I have an akka actor for sending post requests to my google fcm server. The actor takes a list of ids and should make as many req...
(1) odpowiedzi
2016-12-28 17:12 Elegant way of reusing akka-stream flows »
I am looking for a way to easily reuse akka-stream flows. I treat the Flow I intend to reuse as a function, so I would like to keep its signature lik...
(2) odpowiedzi
2016-12-26 14:12 Allow single connection with Akka stream as tcp server »
I am trying to build a simple tcp server using Akka streams. Tcp() .bind(props.host, props.port) .to(Sink.foreach(_.handleWith(handler))) .run...
(1) odpowiedzi
2016-12-06 10:12 Akka Stream Option output »
I have created an Akka Stream which has a simple Source, Flow and Sink. With this I can easily send elements through it. Now I want to change this str...
(3) odpowiedzi
2016-12-03 09:12 Flow which transforms List[A] into List[B] with flattening, given another Flow which transforms A to List[B] »
I have an "inner" flow which transforms A into List[B]. I'd like to create a Flow which transforms List[A] into List[B] by invoking the "inner" flow o...
(1) odpowiedzi
2016-12-01 12:12 Akka HTTP Websocket, how to identify connections inside of actor »
I'm working on simple mulitplayer game in scala that I would like to expose through websockets for JS clients. Here is my WebsocketServer class cl...
(1) odpowiedzi
2016-11-22 14:11 Handle Akka stream's first element specially »
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 sourc...
(2) odpowiedzi
2016-11-18 18:11 Why Source.fromIterator expects a Function0[Iterator[T]] as a parameter instead of Iterator[T]? »
Based on: source code I don't get why the parameter of Source.fromIterator is Function0[Iterator[T]] instead of Iterator[T]. Is there a pratical rea...
(1) odpowiedzi
2016-10-07 06:10 Create backpressure from a Future inside an Akka stream »
I'm new to Akka streams and streams in general so I might have completely misunderstood something at a conceptual level, but is there any way I can cr...
(1) odpowiedzi
2016-09-28 11:09 How to deal with source that emits Future[T]? »
Let's say I have some iterator: val nextElemIter: Iterator[Future[Int]] = Iterator.continually(...) And I want to build a source from that itera...
(1) odpowiedzi