akka / alpakka-samples

Example projects building Reactive Integrations using Alpakka

Alpakka samples

Alpakka documentation

Akka is licensed under the Business Source License 1.1, please see the Akka License FAQ.

alpakka-samples's Issues

bug: akka-sample-persistence-dc-java not working

README.md in akka-sample-persistence-dc-java is wrong
and even trying to point to the real class also fails

 mvn exec:java -Dexec.mainClass="sample.persistence.res.MainApp" -Dexec.args="cassandra"

with

java.lang.ClassNotFoundException: sample.persistence.res.MainApp
    at org.codehaus.mojo.exec.URLClassLoaderBuilder$ExecJavaClassLoader.loadClass (URLClassLoaderBuilder.java:198)
    at java.lang.ClassLoader.loadClass (ClassLoader.java:521)
    at org.codehaus.mojo.exec.ExecJavaMojo$1.run (ExecJavaMojo.java:271)
    at java.lang.Thread.run (Thread.java:834)

Also the name of the project in the pom.xml is different from the name of the folder. Which one is correct?

SQS read - Upstream failed. java.util.concurrent.CompletionException

When am trying to run your code, I get this run time exception being thrown. I have my AWS SQS queue configured and the URLs replaced in the source code. Not sure if I am missing anything else?

SEVERE: [sending to publish queue] Upstream failed. java.util.concurrent.CompletionException: akka.pattern.AskTimeoutException: Ask timed out on [Actor[akka://default/user/$a#923390501]] after [2000 ms]. Message of type [java.lang.String]. A typical reason for AskTimeoutException is that the recipient actor didn't send a reply. at java.util.concurrent.CompletableFuture.encodeThrowable(CompletableFuture.java:292) at java.util.concurrent.CompletableFuture.completeThrowable(CompletableFuture.java:308) at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:593) at java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:577) at java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:474) at java.util.concurrent.CompletableFuture.completeExceptionally(CompletableFuture.java:1977) at scala.concurrent.java8.FuturesConvertersImpl$CF.apply(FutureConvertersImpl.scala:21) at scala.concurrent.java8.FuturesConvertersImpl$CF.apply(FutureConvertersImpl.scala:18) at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:60) at scala.concurrent.BatchingExecutor$Batch.processBatch$1(BatchingExecutor.scala:63) at scala.concurrent.BatchingExecutor$Batch.$anonfun$run$1(BatchingExecutor.scala:78) at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12) at scala.concurrent.BlockContext$.withBlockContext(BlockContext.scala:81) at scala.concurrent.BatchingExecutor$Batch.run(BatchingExecutor.scala:55) at scala.concurrent.Future$InternalCallbackExecutor$.unbatchedExecute(Future.scala:870) at scala.concurrent.BatchingExecutor.execute(BatchingExecutor.scala:106) at scala.concurrent.BatchingExecutor.execute$(BatchingExecutor.scala:103) at scala.concurrent.Future$InternalCallbackExecutor$.execute(Future.scala:868) at scala.concurrent.impl.CallbackRunnable.executeWithValue(Promise.scala:68) at scala.concurrent.impl.Promise$DefaultPromise.$anonfun$tryComplete$1(Promise.scala:284) at scala.concurrent.impl.Promise$DefaultPromise.$anonfun$tryComplete$1$adapted(Promise.scala:284) at scala.concurrent.impl.Promise$DefaultPromise.tryComplete(Promise.scala:284) at akka.pattern.PromiseActorRef$.$anonfun$apply$1(AskSupport.scala:650) at akka.actor.Scheduler$$anon$4.run(Scheduler.scala:205) at scala.concurrent.Future$InternalCallbackExecutor$.unbatchedExecute(Future.scala:870) at scala.concurrent.BatchingExecutor.execute(BatchingExecutor.scala:109) at scala.concurrent.BatchingExecutor.execute$(BatchingExecutor.scala:103) at scala.concurrent.Future$InternalCallbackExecutor$.execute(Future.scala:868) at akka.actor.LightArrayRevolverScheduler$TaskHolder.executeTask(LightArrayRevolverScheduler.scala:328) at akka.actor.LightArrayRevolverScheduler$$anon$3.executeBucket$1(LightArrayRevolverScheduler.scala:279) at akka.actor.LightArrayRevolverScheduler$$anon$3.nextTick(LightArrayRevolverScheduler.scala:283) at akka.actor.LightArrayRevolverScheduler$$anon$3.run(LightArrayRevolverScheduler.scala:235) at java.lang.Thread.run(Thread.java:748) Caused by: akka.pattern.AskTimeoutException: Ask timed out on [Actor[akka://default/user/$a#923390501]] after [2000 ms]. Message of type [java.lang.String]. A typical reason for AskTimeoutException is that the recipient actor didn't send a reply.

Move Elasticsearch self-contained example from Alpakka Docs

Short description

Elasticsearch self-contained example (https://doc.akka.io/docs/alpakka/current/examples/elasticsearch-samples.html) should be moved to this repository as a step-by-step example (as Kafka example was: #13).

Move FTP self-contained example from Alpakka Docs

Short description

FTP self-contained example (https://doc.akka.io/docs/alpakka/current/examples/ftp-samples.html) should be moved to this repository as a step-by-step example (as Kafka example was: #13).

Update to Alpakka 3.0.0 and Alpakka Kafka 2.1.0

Akka HTTP, CSV to Kafka: add Java code

Short description

Parts of that example exist in Java in https://doc.akka.io/docs/alpakka/current/examples/csv-samples.html#example-fetch-csv-from-internet-and-publish-the-data-as-json-to-kafka
This would need to be split into the same steps as in the Scala example and needs a few additions.

Update to Alpakka 5.0

Example idea: Streaming HTTP download and XML parsing

Short description

For example, the GLEI files from https://www.gleif.org/en/lei-data/gleif-concatenated-file/download-the-concatenated-file# are a great use case for streaming XML parsing.

Details

The files are in ZIP format which we don't have good support for right now (see akka/alpakka#658).

New example: publish events from some queue to connected websocket clients

Something of that kind seems to come up quite often. One of the questions here is whether you would create a consumer for the queue (e.g. kafka, or some pubsub) per client or if you would try to cache the consumer in the server and put it behind a BroadcastHub so you can more efficiently handle multiple WS clients.

Update Alpakka Samples to Scala 2.13 and Akka 2.6

Move JMS self-contained example from Alpakka Docs

Short description

JMS self-contained example (https://doc.akka.io/docs/alpakka/current/examples/jms-samples.html) should be moved to this repository as a step-by-step example (as Kafka example was: #13).

Akka Kafka Sample Problem

Hi,

When I am trying to run the Kafka Akka sample I am having a problem in this line of code, in line 103 of Main.java;
.run(actorSystem);

Here my IDE is saying that it's expecting a Materializer, not an ActorSystem

Here are the library versions i am using;

Maybe I have got something wrong?

Thanks

MQTT to S3: Adapt to the latest Alpakka S3 API

Upgrade to Alpakka 2.0.0-RC1

Adapt to new SQS API

Short description

Alpakka SQS changed the API in 1.0.1, the example should show that API.

Remove studentify from sample projects

Short description

The examples currently use the studentify training aid to instruct users how to interatively develop any given example. This is good for training purposes, but it can make quick references from documentation difficult, especially since the studentify implementation is not explained to the user. I recommend reverting these examples to the standard SBT scala project directory structure and remove the studentify SBT code. We can tag the repo before this change if we want to explore providing Alpakka training examples some time in the future.

Could there be a Scala version available?

Could there be a Scala version available?

Create a site and deploy to ghPages

The alpakka-sample-http-csv-to-kafka example is capable of creating a site showing step-by-step changes to the example. This could be auto-deployed to ghPages.

Fix Publishing

Publishing seems broken since I tried to move it into a GH workflow.

https://github.com/akka/alpakka-samples/actions/workflows/publish.yml

Fix csv source for the alpakka-sample-http-csv-to-kafka

The nasdaq changed the way they share data with the outside world.
Just to see it working I've used another open source csv

val uriCsv = "https://www.stats.govt.nz/assets/Uploads/Annual-enterprise-survey/Annual-enterprise-survey-2019-financial-year-provisional/Download-data/annual-enterprise-survey-2019-financial-year-provisional-csv.csv"

It's probably not the best link to use but currently the project just doesn't work because of a missing source.

bug: akka-sample-distributed-workers-scala doesn't work with JRE17

Exception (java.lang.AssertionError) encountered during startup: java.lang.reflect.InaccessibleObjectException: Unable to make field private int java.io.FileDescriptor.fd accessible: module java.base does not "opens java.io" to unnamed module @41a962cf

We need to add instructions to `--add-open' in the README.md