Apache Kafka is an event streaming platform that aids developers in the development of event-driven architectures. Rather than using REST APIs for point-to-point communication, Kafka’s paradigm involves applications sending messages (events) to a pipeline, which can subsequently be consumed by consumers. Producers have no idea who and how their data is being consumed. Consumers, on the other hand, are not bound to producers and can consume messages at any place in the queue. The decoupling between producers and consumers that event-driven architecture relies on is achieved using this architecture.
The best user experience is what today’s app users desire. They’re used to using all of their gadgets to access their apps (computers, mobile phones, tablets, etc). Developers are continuously collaborating with strong technologies that can handle thousands of requests per second as platforms continue to shift to Software as a Service (SaaS). This is where Apache Kafka comes in, a powerful tool that is well-known for its ability to handle high-volume situations.
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Gradle build is a software development tool that is well-known for its adaptability. To automate the building of apps, a build automation tool is employed. Compiling, linking, and packaging the code are all part of the development process. With the use of build automation technologies, the process becomes more streamlined.
Its ability to construct automation in languages like Java, Scala, Android, C/C++, and Groovy has made it popular. Over XML, the tool provides groovy-based DSL. Gradle is a platform for developing, testing, and delivering applications.
Apache Kafka: A Quick Overview
Apache Kafka is a distributed streaming platform that interacts with applications using the publish/subscribe message pattern and is meant to create long-lasting messages.
Let’s take a closer look at those ideas.
Contents
1. Platform for Distributed Streaming
When you want to use Kafka, you must first start its broker, which is a simple Kafka instance operating on a system like any other server. The broker is in charge of sending, receiving, and storing messages to the disc.
To ensure Kafka can manage a high-throughput of messages, a single broker is insufficient. This is accomplished by a large number of brokers cooperating and interacting with one another at the same time.
One or more brokers are combined in a Kafka cluster. Instead of connecting to a single node, your programme connects to a cluster, which takes care of all the distributed details.
2. Messaging System That Allows You To Publish/Subscribe And Send Long-Lasting Messages
In distributed systems, the publish/subscribe pattern is ubiquitous. The basic structure of this pattern in Kafka is depicted in the graphic below:
Producers and Consumers, the two components that have yet to be stated.
An application that delivers messages to the cluster is referred to as a Producer. The cluster then chooses which broker will keep them and transmits them to the chosen brokers.
Consumers are on the other hand. A consumer is a programme that connects to the cluster and receives messages from the producers. Any application that wants to consume messages sent by producers has to connect to Kafka.
3. Install Kafka
Kafka is an open-source messaging system that is easy to set up and use.
Visit the Kafka website to obtain a copy. This compressed file’s contents should be extracted into a folder of your choice.
Go to the bin folder within the Kafka directory. Many bash scripts for operating a Kafka application may be found in this directory. You’ll find the identical scripts in the windows folder if you’re using Windows. If you’re using a Microsoft operating system, you can just use the comparable Windows commands.
4. To manage your Kafka cluster, start Zookeeper.
Apache Kafka is always deployed as a distributed system. This means that your cluster will face certain distributed issues along the way, such as synchronizing configurations or electing a cluster leader.
To keep track of that information, Kafka employs Zookeeper. However, don’t bother about downloading it. Kafka is pre-installed with Zookeeper, making it simple to get started.
Let’s get a Zookeeper instance started! Run the following command within your Kafka directory’s bin folder:
./zookeeper-server-start.sh ../config/zookeeper.properties
5. Establish a Kafka Broker
The broker will now be run. Run the following command from a different terminal, using the bin folder as a source:
./kafka-server-start.sh ../config/server.properties
6. Make a Topic in Kafka
You can define a subject to start delivering messages from a producer once the broker and Zookeeper are up and running. Just as you did in the previous steps, you’ll run the following command within the bin folder:
./kafka-topics.sh –create –topic myTopic -zookeeper \
localhost:2181 –replication-factor 1 –partitions 1
7. Make a Java + Kafka app
- Maven Project is a project that was started by a group of people who wanted to
- Java is the programming language that is used.
- com.okta.java kafka is a group of people who work together to solve problems.
- kafka-java is a piece of software.
Dependencies:
- Web Spring
- Apache Kafka for Spring
You can also use the command line to generate the project.
- curl https://start.spring.io/starter.zip -d language=java \
- -d dependencies=web,kafka \
- -d packageName=com.okta.javakafka \
- -d name=kafka-java \
- -d type=maven-project \
- -o kafka-java.zip
8. Using Your Java App to Send Messages to a Kafka Topic
Configuring the producers inside your Java programme is the first step in creating a producer that may send messages. Let’s accomplish just that by creating a configuration class.
Create a class in it of src/main/java/com/okta/javakafka/configuration folder, and a ProducerConfiguration.
9. In a Java application, consume messages from a Kafka topic
To enable the consumer to find the Kafka Broker, you’ll need to set configurations just like the producer. Create a class inside src/main/java/com/okta/javakafka/configuration
10. Java Kafka Application Security
Right now, your application isn’t very safe. Despite the fact that you are prepared to manage a large number of messages in a distributed environment, anyone who can identify the link to your endpoints can access those messages. This is a serious flaw, therefore let’s make sure it’s dealt with properly.
Only authenticated users will be able to access your endpoints, thus you’ll need OAuth 2.0.
11. Set up an account with Okta.
Create an account with Okta if you don’t have one currently. Follow the steps below after you’ve completed registration:
Please enter your username and password to gain access to your account.
Select Applications > Add Application from the drop-down menu. The following page will be displayed.
- Choose Web and click on to Next.
- Fill in the following things in the form:
- Name: Bootiful Kafka
- Base URIs: http://localhost:8080
- Login redirect URLs: http://localhost:8080/login/oauth2/code/okta
- Click on Done.
12. User Authentication Secures Your Java App
To begin, include Okta’s library in your project. Add the following dependent to your pom.xml in the dependencies section with
<dependency>
<groupId>com.okta.spring</groupId>
<artifactId>okta-spring-boot-starter</artifactId>
<version>1.3.0</version>
</dependency>