Spring Boot + Kafka + Kafka UIローカル環境準備（docker-compose）

Kafka使ってstreamアプリケーション作るためのローカル環境準備

を使いつつ、producerとconsumerをSpringBootで準備。疎通用。

docker-compose

services:
  kafka:
    image: apache/kafka:latest
    container_name: kafka
    ports:
      - "9092:9092"
      - "9093:9093"
    environment:
      KAFKA_NODE_ID: 1
      KAFKA_PROCESS_ROLES: broker,controller
      KAFKA_LISTENERS: PLAINTEXT://0.0.0.0:9092,CONTROLLER://0.0.0.0:9093
      KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://kafka:9092
      KAFKA_CONTROLLER_LISTENER_NAMES: CONTROLLER
      KAFKA_LISTENER_SECURITY_PROTOCOL_MAP: CONTROLLER:PLAINTEXT,PLAINTEXT:PLAINTEXT
      KAFKA_CONTROLLER_QUORUM_VOTERS: 1@kafka:9093
      KAFKA_OFFSETS_TOPIC_REPLICATION_FACTOR: 1
      KAFKA_TRANSACTION_STATE_LOG_REPLICATION_FACTOR: 1
      KAFKA_TRANSACTION_STATE_LOG_MIN_ISR: 1
      KAFKA_GROUP_INITIAL_REBALANCE_DELAY_MS: 0
      KAFKA_NUM_PARTITIONS: 3

  producer:
    build:
      context: ./producer
    container_name: kafka-producer
    depends_on:
      - kafka
    environment:
      SPRING_KAFKA_BOOTSTRAP_SERVERS: kafka:9092

  consumer:
    build:
      context: ./consumer
    container_name: kafka-consumer
    depends_on:
      - kafka
    environment:
      SPRING_KAFKA_BOOTSTRAP_SERVERS: kafka:9092

  kafka-ui:
    image: provectuslabs/kafka-ui:latest
    container_name: kafka-ui
    ports:
      - "8080:8080"
    environment:
      KAFKA_CLUSTERS_0_NAME: local-kafka
      KAFKA_CLUSTERS_0_BOOTSTRAPSERVERS: kafka:9092
      KAFKA_CLUSTERS_0_METRICS_PORT: 8080
    depends_on:
      - kafka

ディレクトリ構成

my-kafka-spring-app/
├── docker-compose.yml
├── producer/
│   ├── Dockerfile
│   ├── build.gradle
│   └── src/
│       └── main/
│           ├── java/
│           │   └── com/example/kafka/
│           │       ├── KafkaProducerApplication.java
│           │       └── controller/
│           │           └── MessageController.java
│           └── resources/
│               └── application.yml
├── consumer/
│   ├── Dockerfile
│   ├── build.gradle
│   └── src/
│       └── main/
│           ├── java/
│           │   └── com/example/kafka/
│           │       ├── KafkaConsumerApplication.java
│           │       └── listener/
│           │           └── MessageListener.java
│           └── resources/
│               └── application.yml

producer

ディレクトリ構成

producer/
├── build.gradle
├── Dockerfile
└── src/
    └── main/
        ├── java/
        │   └── com/example/kafka/
        │       ├── KafkaProducerApplication.java
        │       └── controller/
        │           └── MessageController.java
        └── resources/
            └── application.yml

build.gradle

plugins {
    id 'org.springframework.boot' version '3.1.5'
    id 'io.spring.dependency-management' version '1.1.3'
    id 'java'
}

group = 'com.example.kafka'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '17'

repositories {
    mavenCentral()
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-web'
    implementation 'org.springframework.kafka:spring-kafka'
}

Dockerfile

FROM gradle:8.4-jdk17 AS builder
WORKDIR /app
COPY . /app
RUN gradle bootJar --no-daemon

FROM eclipse-temurin:17-jre
WORKDIR /app
COPY --from=builder /app/build/libs/*.jar app.jar
ENTRYPOINT ["java", "-jar", "app.jar"]

KafkaProducerApplication.java

package com.example.kafka;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class KafkaProducerApplication {
    public static void main(String[] args) {
        SpringApplication.run(KafkaProducerApplication.class, args);
    }
}

MessageController.java

package com.example.kafka.controller;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/api/messages")
public class MessageController {

    private final KafkaTemplate<String, String> kafkaTemplate;

    @Value("${kafka.topic:test-topic}")
    private String topic;

    public MessageController(KafkaTemplate<String, String> kafkaTemplate) {
        this.kafkaTemplate = kafkaTemplate;
    }

    @PostMapping
    public String sendMessage(@RequestBody String message) {
        kafkaTemplate.send(topic, message);
        return "Message sent to Kafka: " + message;
    }
}

application.yml

server:
  port: 8080

spring:
  kafka:
    bootstrap-servers: ${SPRING_KAFKA_BOOTSTRAP_SERVERS:kafka:9092}
    producer:
      key-serializer: org.apache.kafka.common.serialization.StringSerializer
      value-serializer: org.apache.kafka.common.serialization.StringSerializer

kafka:
  topic: test-topic

consumer

ディレクトリ構成

consumer/
├── build.gradle
├── Dockerfile
└── src/
    └── main/
        ├── java/
        │   └── com/example/kafka/
        │       ├── KafkaConsumerApplication.java
        │       └── listener/
        │           └── MessageListener.java
        └── resources/
            └── application.yml

bulid.gradleとDockerfileはproducerと同じ内容

KafkaConsumerApplication.java

package com.example.kafka;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class KafkaConsumerApplication {
    public static void main(String[] args) {
        SpringApplication.run(KafkaConsumerApplication.class, args);
    }
}

MessageListener.java

package com.example.kafka.listener;

import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Component;

@Component
public class MessageListener {

    @KafkaListener(topics = "${kafka.topic:test-topic}", groupId = "test-group")
    public void listen(String message) {
        System.out.println("Received message from Kafka: " + message);
    }
}

application.yml

spring:
  kafka:
    bootstrap-servers: ${SPRING_KAFKA_BOOTSTRAP_SERVERS:kafka:9092}
    consumer:
      group-id: test-group
      auto-offset-reset: earliest
      key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
      value-deserializer: org.apache.kafka.common.serialization.StringDeserializer

kafka:
  topic: test-topic

接続確認

test-topicに対してメッセージ送信

messageがtopicにあることを確認

consumerがメッセージを処理したことをログで確認
kafka-consumer | Received message from Kafka: hello

おわり