The purpose of the series is to uncover some of theAkka Streams essentials. There are few major principles that lie behinds this topic. They are: Asynchronous Backpressured Incremental And potentially infinite STREAMS of elements These terms are inextricably linked to the Reactive Streams concepts: Reactive Streams is an initiative to...
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Hands-on: Akka + Akka HTTP + Akka Streams + Alpakka Java Tutorial
Which technologies will be used Today Akka offers a great technology stack that is built on top of the Actor paradigm. It delivers a great Akka Stream API which together with a simplified concurrency model and great abilities for use and control backpressure empowers us with top-class tools to create...
Continue reading...Literally a silver bullet for sbt merge strategies in projects using Spark structured streaming and Kafka
Recently it was an intolerable pain for me to build a so-called fat jar‘s for my Spark jobs in Scala using sbt. Well, what’s was happening there? (NOTE: if you’re don’t use fat jars to submit Spark jobs and —this is a better way to deal with Spark though– then...
Continue reading...Get custom parameters from application.conf in Akka HTTP
Hi there! I decided to introduce a new type of posts which called a “Quick Tip”. So this post will be the first in that category. It is a common situation when you find some interesting feature (and maybe not only for you) but it is pretty small for creating...
Continue reading...“No dockerHost given, no DOCKER_HOST environment variable” error in Ubuntu
I was struggling against an issue of: while trying to deploy a project to docker using docker-maven-plugin. Need to say that I’ve installed and created a docker-machine and then exported all related env‘s to the Ubuntu environment variables. Then I tried to execute the following maven goals using maven from...
Continue reading...Debugging drools project using KieRuntimeLogger (audit log)
I’m currently working under a project which utilizes Red Hat Decision Manager as a runtime to provide a real-time decisions for banking. It is not a secret that it has drools rule engine under the hood. It’s possible to debug drools applications using different tools and approaches, the one which...
Continue reading...Immutable class built on mutable underlying object
I’m currently reading the “Java Concurrency in Practice” by Brian Goetz. There are a plenty of brilliant code snippets here concerning concurrency in Java. So I want to analyze some of the examples to understand it more detailed. Today we will talk about immutable objects which contain a mutable objects...
Continue reading...Backup unhandled events to Kafka with shutdown hook using @PreDestroy
I was struggling with a task which I’ve mentally called “a distributed back-ups using Kafka”. So the idea in a few words was that we had a service used to invoke database functions. The service had a few RESTful endpoints and was accepting a predefined set of input objects along...
Continue reading...Visualizing Kafka Streams topology
Kafka Streams generates an ASCII Kafka Topology and prints it to the console during startup. These ASCII topologies can be huge and hard to understand. There is a handy tool which allows you to visualize your ASCII topology to a hand drawn diagram. Just copy the topology from the console...
Continue reading...Experience in WebFlux (Netty) highload optimization
For the last three weeks our team was brainstorming a strange bug. We have a Spring Boot-based microservice deployed on OpenShift cluster which provides a REST endpoint, retrieving a user data from a NoSQL database. For some unknown reasons we were unable to gain more requests-per-second. The mystic power was...
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