Stream on Micha Kops' Tech Notes

Messaging with NATS and Java

Tue, 26 Nov 2024 00:00:00 +0100

Figure 1. NATS Architecture Component Diagram

NATS is a high-performance messaging system that offers simplicity, speed, and scalability. It is particularly suited for building distributed systems and microservices.

This article demonstrates how to integrate NATS with Java, showcasing the essential steps to set up, connect, and publish/subscribe to messages.

Prerequisites

Before diving in, we should ensure to have the following installed:

Java Development Kit (JDK) 11 or later.
Maven or Gradle for dependency management.
Docker (optional).

Implementing Reactive Client-Server Communication over TCP or Websockets with RSocket and Java

Sun, 25 Nov 2018 00:00:00 +0100

Reactive design or reactive architecture has an impact on how modern software systems are implemented. RSocket is a project that aims to adapt the benefits of the patterns described in the Reactive Manifesto and resulting tools like Reactive Streams or Reactive Extensions to a formal new communication protocol.

RSocket works with TCP, WebSockets and Aeron transport layers and offers additional features like session resumption.

In the following tutorial I’m going to demonstrate how to implement simple client-server communication over TCP and Websockets for different interaction models like request-response, request-stream, fire-and-forget and event subscription.

Unix-like data pipelines with Java 8 Streams and UStream

Sun, 08 Nov 2015 00:00:00 +0100

We all love the simplicity when chaining commands and pipes in an Unix derivative environment.

UStream takes this approach and extends Java 8′s stream API to mimic some of the well known commands and apply them on streams.

In the following tutorial, I’d like to share some slim examples for using UStream.

Figure 1. Data pipelines with UStream

Dependencies

We simply need to add one dependency to our pom.xml (using Maven): io.github.benas:ustream:0.2

Playing with Java 8 Lambda Expressions

Sun, 22 Sep 2013 00:00:00 +0200

Many articles have been written about JSR 335 aka Lambda Expressions for the Java^TM Programming Language but I like to try new things out for myself and that’s why I’d like to share my snippets here.

Figure 1. Lambda Hacking using the NetBeans Developer Version

Setup JDK and IDE

It takes just some short steps to setup your environment …

Download and install the Java 8 JDK with lambda support
Download and install the NetBeans IDE Development version
Configure NetBeans to use the Java 8 JDK (> Manage Platforms…)

Kafka Snippets

Mon, 01 Mar 2010 00:00:00 +0100

Start an Image with kcat / kafka-cat for Debugging

kubectl -n NAMESPACE run "$(whoami)-debug" -it --rm \
    --image=confluentinc/cp-kafkacat:6.1.9 \
    --restart=Never \
    -- bash

Dockerfile for Kafka Analysis Container with different Tools

With jq, kafka console tools, schema registry tools and kafkacat installed ….

Dockerfile

FROM confluentinc/cp-kafka:6.2.1 as cp-kafka
FROM confluentinc/cp-schema-registry:6.2.1 as cp-schema-registry

FROM debian:10-slim
ARG DEBIAN_FRONTEND=noninteractive

# Install necessary tools
RUN apt-get update && apt-get install -y \
    curl \
    jq \
    yq \
    && rm -rf /var/lib/apt/lists/*

# Install kafkacat binary
RUN apt-get update && apt-get install -y kafkacat && rm -rf /var/lib/apt/lists/*

# Copy Kafka binaries
COPY --from=cp-kafka /usr/bin/kafka-* /usr/bin/
COPY --from=cp-schema-registry /usr/bin/schema-registry* /usr/bin/

# Copy entrypoint script
COPY entrypoint.sh /usr/bin/entrypoint.sh
RUN chmod +x /usr/bin/entrypoint.sh

ENTRYPOINT ["/usr/bin/entrypoint.sh"]