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:\Windows\System32\drivers\etc\hosts 里写入 172.16.23.203 kafka

物联网架构成长之路(28)-Docker练习之MQ中间件(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

物联网架构成长之路(28)-Docker练习之MQ中间件(Kafka)

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();

     }

 }