物联网架构成长之路(28)-Docker练习之MQ中间件(Kafka)

0. 前言

　　消息队列MQ，这个在一般的系统上都是会用到的一个中间件，我选择Kafka作为练手的一个中间件，Kafka依赖Zookeeper。Zookeeper安装上一篇博客已经介绍过了。

1. Kafka Image构建

　　Dockerfile

FROM openjdk:8-jdk-alpine

RUN apk add --no-cache bash && rm -rf /var/cache/apk/* && /bin/bash

RUN wget http://mirrors.aliyun.com/apache/kafka/2.0.1/kafka_2.12-2.0.1.tgz && 
    tar -zxvf kafka_2.12-2.0.1.tgz && 
    rm -rf kafka_2.12-2.0.1.tgz && 
    mv kafka_2.12-2.0.1 /var/app/

ENV PATH /var/app/bin:$PATH

COPY env.sh /env.sh
RUN chmod +x env.sh

EXPOSE 9092

ENTRYPOINT ["/env.sh"]

　　env.sh

#!/bin/sh

BROKER_ID=${BRODER_ID:-"0"}
LISTENERS=${LISTENERS:-"PLAINTEXT://:9092"}
ZOOKEEPER_CONNECT=${ZOOKEEPER_CONNECT:-"localhost:2181"}

sed -i "s/^broker.id=.*$/broker.id=$BROKER_ID/" /var/app/config/server.properties
sed -i "s;^#listeners=.*$;listeners=$LISTENERS;g" /var/app/config/server.properties
sed -i "s/^zookeeper.connect=.*$/zookeeper.connect=$ZOOKEEPER_CONNECT/" /var/app/config/server.properties

sed -i "s#/tmp/kafka-logs#/data#g" /var/app/config/server.properties

/var/app/bin/kafka-server-start.sh /var/app/config/server.properties

2. docker-compose配置Zookeeper、zkui、Kafka

　　docker-compose.yml

version: '3'
services:
    zookeeper:
        image: registry.cn-shenzhen.aliyuncs.com/wunaozai/zookeeper
        ports:
            - 2181:2181
    zkui:
        image: registry.cn-shenzhen.aliyuncs.com/wunaozai/zkui
        ports:
            - 9090:9090
        environment:
            - ZK_SERVER=zookeeper:2181
    kafka:
        image: registry.cn-shenzhen.aliyuncs.com/wunaozai/kafka
        ports:
            - 9092:9092
        environment:
            - BROKER_ID=1
            - LISTENERS=PLAINTEXT://kafka:9092
            - ZOOKEEPER_CONNECT=zookeeper:2181
        volumes:
            - /root/workspace/docker/kafka/kafka/data:/data

　　启动docker-compose、并通过zkui预览、注意由于kafka的监听是使用域名方式，因此需要往 /etc/hosts 中写入  127.0.0.1 kafka， 如果客户端开发，在Windows系统的，要往 C:WindowsSystem32driversetchosts 里写入 172.16.23.203  kafka

3. Kafka读写

　　创建主题(Topic)

./bin/kafka-topics.sh --create --zookeeper 172.16.23.203:2181 --replication-factor 1 --partitions 1 --topic wunaozai

　　查看主题(Topic)

./bin/kafka-topics.sh --list --zookeeper 172.16.23.203:2181 --list

　　发送消息(生产者)

./bin/kafka-console-producer.sh --broker-list 172.16.23.203:9092 --topic wunaozai

　　消费消息(消费者)

./bin/kafka-console-consumer.sh --bootstrap-server kafka:9092 --topic wunaozai

4. Kafka Java Client 测试

　　POM依赖

 <!-- https://mvnrepository.com/artifact/org.apache.kafka/kafka-clients -->
 <dependency>
     <groupId>org.apache.kafka</groupId>
     <artifactId>kafka-clients</artifactId>
     <version>2.0.1</version>
 </dependency>

　　生产者ProducerSample.java

package demo.kafka;

import java.util.HashMap;
import java.util.Map;

import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.Producer;
import org.apache.kafka.clients.producer.ProducerRecord;

public class ProducerSample {

    public static void main(String[] args) {
        Map<String, Object> props = new HashMap<>();
        props.put("zk.connect", "172.16.23.203:2181");
        props.put("bootstrap.servers", "172.16.23.203:9092");
        props.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        props.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
        props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
        props.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
        
        String topic = "wunaozai";
        Producer<String, String> producer = new KafkaProducer<>(props);
        producer.send(new ProducerRecord<String, String>(topic, "key1", "value111"));
        producer.send(new ProducerRecord<String, String>(topic, "key2", "value222"));
        producer.send(new ProducerRecord<String, String>(topic, "key3", "value333"));
        producer.close();
    }
}

　　消费者 ConsumerSample.java

package demo.kafka;

import java.time.Duration;
import java.util.Arrays;
import java.util.Properties;

import org.apache.kafka.clients.consumer.Consumer;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;

public class ConsumerSample {

    public static void main(String[] args) {
        String topic = "wunaozai";
        
        Properties props = new Properties();
        props.put("bootstrap.servers", "172.16.23.203:9092");
        props.put("group.id", "JLGroup");// Consumer Group Name
        props.put("enable.auto.commit", "true");// Consumer 的 offset 是否自动提交
        props.put("auto.commit.interval.ms", "1000");// 自动提交 offset 到 zookeeper
        props.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
        props.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
        Consumer<String, String> consumer = new KafkaConsumer<>(props);
        consumer.subscribe(Arrays.asList(topic));
        try {
            while (true) {
                //Duration timeout = Duration.ofMillis(10000);
                Duration timeout = Duration.ofSeconds(5); 
                ConsumerRecords<String, String> records = consumer.poll(timeout);
                for (ConsumerRecord<String, String> record : records)
                    System.out.printf("partition = %d, offset = %d, key = %s, value = %s%n", record.partition(), record.offset(), record.key(), record.value());
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        consumer.close();
    }
}

　　ProducerSample 生产消息，通过./bin/kafka-console-consumer.sh 消费消息

　　./bin/kafka-console-producer.sh 生产消息，通过ConsumerSample 消费消息

　　docker-compose 部分日志 

5. 小结

　　一路练习下来，发现这个Kafka配置还是有点复杂的，就先了解到这里，以后再深入了解。一步一步慢慢来。

参考资料:

　　https://hub.docker.com/r/wurstmeister/kafka/
　　https://raw.githubusercontent.com/wurstmeister/kafka-docker/master/docker-compose.yml
　　https://github.com/wurstmeister/kafka-docker
　　https://github.com/apache/kafka
　　https://www.cnblogs.com/smail-bao/p/7794636.html
　　https://www.cnblogs.com/wunaozai/p/8249657.html

本文地址: https://www.cnblogs.com/wunaozai/p/9985054.html