6 hours ago

[Spring Boot] 3 Ways of Dockerizing Spring Boot Application

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…

Docker

1 min read

6 days ago

[Spring Boot] Batching GraphQL Queries with @BatchMapping

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…

Spring Boot

4 min read

6 days ago

[Spring Boot] Routing Requests with Spring Cloud Gateway

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…

Spring Cloud Gateway

2 min read

Jun 14

[Spring Boot] Feign Client and JDK Dynamic Proxy

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…

Spring Boot

4 min read

Jun 13

[Spring Boot] Unit Testing Kafka Producer with Producer Listener

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. …

Kafka

2 min read

Jun 3

[Spring Boot] Unit Testing Kafka Producer with Producer Callback

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…

Kafka

1 min read

Jun 1

[React] Routing to an Error Page with axios interceptors

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 …

React

3 min read

May 15

[Docker] Multi-stage Docker Build for React and Spring Boot

React using NPM and Nginx Note that yarn can be used instead of npm. Feel free to use whichever works for your environment. Because my React application makes requests to the Spring Boot backend, nginx.conf was added to set up a reverse proxy. Spring Boot using Maven Note that Java Options can added in CMD. For example, when I set up an acceptance environment where Product Managers can test to accept or reject stories, I used this as CMD instead:

Docker

1 min read

[Docker] Multi-stage Docker Build for React and Spring Boot

React using NPM and Nginx

Note that yarn can be used instead of npm. Feel free to use whichever works for your environment.

Because my React application makes requests to the Spring Boot backend, nginx.conf was added to set up a reverse proxy.

Spring Boot using Maven

Note that Java Options can added in CMD.

For example, when I set up an acceptance environment where Product Managers can test to accept or reject stories, I used this as CMD instead:

CMD ["java", "-Dspring.profiles.active=docker", "-jar", "app.jar"]

May 10

[React] Scrolling to a specific element with useRef()

Demo:

React

1 min read

[React] Scrolling to a specific element with useRef()

Demo:

May 4

[React] Unit Testing with React Router

When writing unit tests, different people have different ideas on how to assert against whether navigating to a different page was successful or not. Let’s say I have a main page that can navigate to a secondary page. In order to navigate, the implementation needs to use useNavigate from react-router-dom. Here is what MainPage looks like: My preferred way of writing a unit test for MainPage to navigate to a different page is:

React

1 min read

[React] Unit Testing with React Router

When writing unit tests, different people have different ideas on how to assert against whether navigating to a different page was successful or not.

Let’s say I have a main page that can navigate to a secondary page. In order to navigate, the implementation needs to use useNavigate from react-router-dom.

Here is what MainPage looks like:

My preferred way of writing a unit test for MainPage to navigate to a different page is:

Note that this approach works with React Router v5 with useHistory as well.

Demo:

[Spring Boot] 3 Ways of Dockerizing Spring Boot Application

[Spring Boot] Batching GraphQL Queries with @BatchMapping

[Spring Boot] Routing Requests with Spring Cloud Gateway

[Spring Boot] Feign Client and JDK Dynamic Proxy

[Spring Boot] Unit Testing Kafka Producer with Producer Listener

[Spring Boot] Unit Testing Kafka Producer with Producer Callback

[React] Routing to an Error Page with axios interceptors

[Docker] Multi-stage Docker Build for React and Spring Boot

[Docker] Multi-stage Docker Build for React and Spring Boot

React using NPM and Nginx

Spring Boot using Maven

[React] Scrolling to a specific element with useRef()

[React] Scrolling to a specific element with useRef()

[React] Unit Testing with React Router

[React] Unit Testing with React Router

J.Kim