Introduction This article will cover the basics of Advanced Message Queuing Protocol (AMQP) and how to write good Integration tests using RabbitMQ in a Reactive Spring Boot application. Advanced Message Queuing Protocol (AMQP) AMQP is a message protocol that deals with publishers and consumers. A message broker (such as RabbitMQ) ensures published messages go to the…

Common Approach Layered Jars For this to work, layers configuration needs to be enabled for spring-boot-maven-plugin. 2. Build the fat jar by running the following command. This will generate a fat jar in the target directory. $ mvn package 3. Check layers by running the following command. Note that this is my…

Previously, I wrote an article covering how to create and test a Spring Boot app with GraphQL. At that time, it used an experimental graphql-spring-boot-starter dependency but now it is officially released as spring-boot-starter-graphql. While I was at a webinar, Korea Spring Meetup with Josh Long, he introduced @BatchMapping annotation…

This article will show a couple of ways on how to route requests to downstream services using Spring Cloud Gateway. In this simple example, the gateway will route to https://dummyjson.com/products. Implementation First of all, spring-cloud-starter-gateway dependency is required. pom.xml should look something similar to the one below. Creating routes via properties The first approach…

While I was reading Head First Design Patterns book, I came across Proxy pattern. Then, I ran into a brief introduction to Invocation Handler in Java. I remembered a conversation almost 3 years ago with a friend of mine that I worked with before via Pivotal App-Tx engagement (now a…

Previously, [Spring Boot] Unit Testing Kafka Producer with EmbeddedKafkaBroker [Spring Boot] Unit Testing Kafka Producer with Producer Callback Introduction This article covers how to write unit tests for Kafka Producers with Producer Listeners. It is similar to Producer Callback implementing ListenableFutureCallback. With this approach, there are a couple of drawbacks in my…

This article covers how to write unit tests for Kafka Producers with callbacks. Callbacks can be useful to handle success cases and failure cases because Kafka Producers are asynchronous. The send() method is asynchronous. When called it adds the record to a buffer of pending record sends and immediately returns…

Recently, I came across a user story where the frontend routes to an Error Page when it fails to communicate with the backend. GIVEN as 000 as user of this product WHEN navigating to a different page THEN I can see an error page when data was not fetched successfully …