如何使用Docker内的kafka服务
2019-01-22 本文已影响12人
金桔文案
基于Docker可以很轻松的搭建一个kafka集群，其他机器上的应用如何使用这个kafka集群服务呢？本次实战就来解决这个问题。
基本情况
整个实战环境一共有三台机器，各自的职责如下图所示：
image.png
整个环境的部署情况如下图：
image.png
版本信息
1.操作系统：Centos7
2.docker：17.03.2-ce
3.docker-compose：1.23.2
4.kafka：0.11.0.3
5.zookeeper：3.4.9
6.JDK：1.8.0_191
7.spring boot：1.5.9.RELEASE
8.spring-kafka：1.3.8.RELEASE
重点介绍
本次实战有几处重点需要注意：
1.spring-kafka和kafka的版本匹配问题，请关注官方文档：https://spring.io/projects/spring-kafka
2.kafka的kafka的advertised.listeners配置，应用通过此配置来连接broker；
3.应用所在服务器要配置host，才能连接到broker；
接下来开始实战吧；
配置host
为了让生产和消费消息的应用能够连接kafka成功，需要配置应用所在服务器的/etc/hosts文件，增加以下一行内容：
192.168.1.101 kafka1
192.168.1.101是docker所在机器的IP地址；
请注意，生产和消费消息的应用所在服务器都要做上述配置；
可能有的读者在此会有疑问：为什么要配置host呢？我把kafka配置的advertised.listeners配置成kafka的IP地址不就行了么？这样的配置我试过，但是用kafka-console-producer.sh和kafka-console-consumer.sh连接kafka的时候会报错"LEADER_NOT_AVAILABLE"。
在docker上部署kafka
1.在docker机器上编写docker-compose.yml文件，内容如下：
version: '2'
services:
zookeeper:
image: wurstmeister/zookeeper
ports:
- "2181:2181"
kafka1:
image: wurstmeister/kafka:2.11-0.11.0.3
ports:
- "9092:9092"
environment:
KAFKA_ADVERTISED_LISTENERS: PLAINTEXT://kafka1:9092
KAFKA_LISTENERS: PLAINTEXT://:9092
KAFKA_ZOOKEEPER_CONNECT: zookeeper:2181
KAFKA_CREATE_TOPICS: "topic001:2:1"
volumes:
- /var/run/docker.sock:/var/run/docker.sock
上述配置中有两处需要注意：
第一，KAFKA_ADVERTISED_LISTENERS的配置，这个参数会写到kafka配置的advertised.listeners这一项中，应用会用来连接broker；
第二，KAFKA_CREATE_TOPICS的配置，表示容器启动时会创建名为"topic001"的主题，并且partition等于2，副本为1；
2.在docker-compose.yml所在目录执行命令docker-compose up -d，启动容器；
3.执行命令docker ps，可见容器情况，kafka的容器名为temp_kafka1_1：
[root@hedy temp]# docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
ba5374d6245c wurstmeister/zookeeper "/bin/sh -c '/usr/..." About an hour ago Up About an hour 22/tcp, 2888/tcp, 3888/tcp, 0.0.0.0:2181->2181/tcp temp_zookeeper_1
2c58f46bb772 wurstmeister/kafka:2.11-0.11.0.3 "start-kafka.sh" About an hour ago Up About an hour 0.0.0.0:9092->9092/tcp temp_kafka1_1
4.执行以下命令可以查看topic001的基本情况：
docker exec temp_kafka1_1 \
kafka-topics.sh \
--describe \
--topic topic001 \
--zookeeper zookeeper:2181
看到的信息如下：
Topic:topic001 PartitionCount:2 ReplicationFactor:1 Configs:
Topic: topic001 Partition: 0 Leader: 1001 Replicas: 1001 Isr: 1001
Topic: topic001 Partition: 1 Leader: 1001 Replicas: 1001 Isr: 1001
源码下载
接下来的实战是编写生产消息和消费消息的两个应用的源码，您可以选择直接从GitHub下载这两个工程的源码，地址和链接信息如下表所示：
image.png
这个git项目中有多个文件夹，本章源码在kafka01103consumer和kafka01103producer这两个文件夹下，如下图红框所示：
image.png
接下来开始编码：
开发生产消息的应用
- 创建一个maven工程，pom.xml内容如下：
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.9.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.bolingcavalry</groupId>
<artifactId>kafka01103producer</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>kafka01103producer</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.kafka</groupId>
<artifactId>spring-kafka</artifactId>
<version>1.3.8.RELEASE</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.28</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
再次强调spring-kafka版本和kafka版本的匹配很重要；
- 配置文件application.properties内容：
#kafka相关配置
spring.kafka.bootstrap-servers=kafka1:9092
#设置一个默认组
spring.kafka.consumer.group-id=0
#key-value序列化反序列化
spring.kafka.consumer.key-deserializer=org.apache.kafka.common.serialization.StringDeserializer
spring.kafka.consumer.value-deserializer=org.apache.kafka.common.serialization.StringDeserializer
spring.kafka.producer.key-serializer=org.apache.kafka.common.serialization.StringSerializer
spring.kafka.producer.value-serializer=org.apache.kafka.common.serialization.StringSerializer
#每次批量发送消息的数量
spring.kafka.producer.batch-size=65536
spring.kafka.producer.buffer-memory=524288
3.发送消息的业务代码只有一个MessageController类：
package com.bolingcavalry.kafka01103producer.controller;
import com.alibaba.fastjson.JSONObject;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.util.concurrent.ListenableFuture;
import org.springframework.web.bind.annotation.*;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.UUID;
/**
* @Description: 接收web请求，发送消息到kafka
* @author: willzhao E-mail: zq2599@gmail.com
* @date: 2019/1/1 11:44
*/
@RestController
public class MessageController {
@Autowired
private KafkaTemplate kafkaTemplate;
@RequestMapping(value = "/send/{name}/{message}", method = RequestMethod.GET)
public @ResponseBody
String send(@PathVariable("name") final String name, @PathVariable("message") final String message) {
SimpleDateFormat simpleDateFormat=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String timeStr = simpleDateFormat.format(new Date());
JSONObject jsonObject = new JSONObject();
jsonObject.put("name", name);
jsonObject.put("message", message);
jsonObject.put("time", timeStr);
jsonObject.put("timeLong", System.currentTimeMillis());
jsonObject.put("bizID", UUID.randomUUID());
String sendMessage = jsonObject.toJSONString();
ListenableFuture future = kafkaTemplate.send("topic001", sendMessage);
future.addCallback(o -> System.out.println("send message success : " + sendMessage),
throwable -> System.out.println("send message fail : " + sendMessage));
return "send message to [" + name + "] success (" + timeStr + ")";
}
}
4.编码完成后，在pom.xml所在目录执行命令mvn clean package -U -DskipTests，即可在target目录下发现文件kafka01103producer-0.0.1-SNAPSHOT.jar，将此文件复制到192.168.1.102机器上；
5.登录192.168.1.102，在文件kafka01103producer-0.0.1-SNAPSHOT.jar所在目录执行命令java -jar kafka01103producer-0.0.1-SNAPSHOT.jar，即可启动生产消息的应用；
开发消费消息的应用
1.创建一个maven工程，pom.xml内容如下：
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.9.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.bolingcavalry</groupId>
<artifactId>kafka01103consumer</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>kafka01103consumer</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.kafka</groupId>
<artifactId>spring-kafka</artifactId>
<version>1.3.8.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
再次强调spring-kafka版本和kafka版本的匹配很重要；
- 配置文件application.properties内容：
#kafka相关配置
spring.kafka.bootstrap-servers=192.168.1.101:9092
#设置一个默认组
spring.kafka.consumer.group-id=0
#key-value序列化反序列化
spring.kafka.consumer.key-deserializer=org.apache.kafka.common.serialization.StringDeserializer
spring.kafka.consumer.value-deserializer=org.apache.kafka.common.serialization.StringDeserializer
spring.kafka.producer.key-serializer=org.apache.kafka.common.serialization.StringSerializer
spring.kafka.producer.value-serializer=org.apache.kafka.common.serialization.StringSerializer
#每次批量发送消息的数量
spring.kafka.producer.batch-size=65536
spring.kafka.producer.buffer-memory=524288
3.消费消息的业务代码只有一个Consumer类，收到消息后，会将内容内容和消息的详情打印出来：
@Component
public class Consumer {
@KafkaListener(topics = {"topic001"})
public void listen(ConsumerRecord<?, ?> record) {
Optional<?> kafkaMessage = Optional.ofNullable(record.value());
if (kafkaMessage.isPresent()) {
Object message = kafkaMessage.get();
System.out.println("----------------- record =" + record);
System.out.println("------------------ message =" + message);
}
}
}
4.编码完成后，在pom.xml所在目录执行命令mvn clean package -U -DskipTests，即可在target目录下发现文件kafka01103consumer-0.0.1-SNAPSHOT.jar，将此文件复制到192.168.1.104机器上；
5.登录192.168.1.104，在文件kafka01103consumer-0.0.1-SNAPSHOT.jar所在目录执行命令java -jar kafka01103consumer-0.0.1-SNAPSHOT.jar，即可启动消费消息的应用，控制台输出如下：
2019-01-01 13:41:41.747 INFO 1422 --- [ main] o.a.kafka.common.utils.AppInfoParser : Kafka version : 0.11.0.2
2019-01-01 13:41:41.748 INFO 1422 --- [ main] o.a.kafka.common.utils.AppInfoParser : Kafka commitId : 73be1e1168f91ee2
2019-01-01 13:41:41.787 INFO 1422 --- [ main] o.s.s.c.ThreadPoolTaskScheduler : Initializing ExecutorService
2019-01-01 13:41:41.912 INFO 1422 --- [ main] c.b.k.Kafka01103consumerApplication : Started Kafka01103consumerApplication in 11.876 seconds (JVM running for 16.06)
2019-01-01 13:41:42.699 INFO 1422 --- [ntainer#0-0-C-1] o.a.k.c.c.internals.AbstractCoordinator : Discovered coordinator kafka1:9092 (id: 2147482646 rack: null) for group 0.
2019-01-01 13:41:42.721 INFO 1422 --- [ntainer#0-0-C-1] o.a.k.c.c.internals.ConsumerCoordinator : Revoking previously assigned partitions [] for group 0
2019-01-01 13:41:42.723 INFO 1422 --- [ntainer#0-0-C-1] o.s.k.l.KafkaMessageListenerContainer : partitions revoked:[]
2019-01-01 13:41:42.724 INFO 1422 --- [ntainer#0-0-C-1] o.a.k.c.c.internals.AbstractCoordinator : (Re-)joining group 0
2019-01-01 13:41:42.782 INFO 1422 --- [ntainer#0-0-C-1] o.a.k.c.c.internals.AbstractCoordinator : Successfully joined group 0 with generation 5
2019-01-01 13:41:42.788 INFO 1422 --- [ntainer#0-0-C-1] o.a.k.c.c.internals.ConsumerCoordinator : Setting newly assigned partitions [topic001-1, topic001-0] for group 0
2019-01-01 13:41:42.805 INFO 1422 --- [ntainer#0-0-C-1] o.s.k.l.KafkaMessageListenerContainer : partitions assigned:[topic001-1, topic001-0]
2019-01-01 13:48:00.938 INFO 1422 --- [ntainer#0-0-C-1] o.a.k.c.c.internals.ConsumerCoordinator : Revoking previously assigned partitions [topic001-1, topic001-0] for group 0
2019-01-01 13:48:00.939 INFO 1422 --- [ntainer#0-0-C-1] o.s.k.l.KafkaMessageListenerContainer : partitions revoked:[topic001-1, topic001-0]
上述内容显示了当前应用消费了两个partition；
6.再启动一个同样的应用，这样每个应用负责一个parititon的消费，做法是在文件kafka01103consumer-0.0.1-SNAPSHOT.jar所在目录执行命令java -jar kafka01103consumer-0.0.1-SNAPSHOT.jar --server.port=8081，看看控制台的输出：
2019-01-01 13:47:58.068 INFO 1460 --- [ main] o.a.kafka.common.utils.AppInfoParser : Kafka version : 0.11.0.2
2019-01-01 13:47:58.069 INFO 1460 --- [ main] o.a.kafka.common.utils.AppInfoParser : Kafka commitId : 73be1e1168f91ee2
2019-01-01 13:47:58.103 INFO 1460 --- [ main] o.s.s.c.ThreadPoolTaskScheduler : Initializing ExecutorService
2019-01-01 13:47:58.226 INFO 1460 --- [ main] c.b.k.Kafka01103consumerApplication : Started Kafka01103consumerApplication in 11.513 seconds (JVM running for 14.442)
2019-01-01 13:47:59.007 INFO 1460 --- [ntainer#0-0-C-1] o.a.k.c.c.internals.AbstractCoordinator : Discovered coordinator kafka1:9092 (id: 2147482646 rack: null) for group 0.
2019-01-01 13:47:59.030 INFO 1460 --- [ntainer#0-0-C-1] o.a.k.c.c.internals.ConsumerCoordinator : Revoking previously assigned partitions [] for group 0
2019-01-01 13:47:59.031 INFO 1460 --- [ntainer#0-0-C-1] o.s.k.l.KafkaMessageListenerContainer : partitions revoked:[]
2019-01-01 13:47:59.032 INFO 1460 --- [ntainer#0-0-C-1] o.a.k.c.c.internals.AbstractCoordinator : (Re-)joining group 0
2019-01-01 13:48:00.967 INFO 1460 --- [ntainer#0-0-C-1] o.a.k.c.c.internals.AbstractCoordinator : Successfully joined group 0 with generation 6
2019-01-01 13:48:00.985 INFO 1460 --- [ntainer#0-0-C-1] o.a.k.c.c.internals.ConsumerCoordinator : Setting newly assigned partitions [topic001-0] for group 0
2019-01-01 13:48:01.015 INFO 1460 --- [ntainer#0-0-C-1] o.s.k.l.KafkaMessageListenerContainer : partitions assigned:[topic001-0]
可见新的进程消费的是0号partition，此时再去看看先启动的进程的控制台，见到了新的日志，显示该进程只消费1号pairtition了：
2019-01-01 13:48:00.955 INFO 1422 --- [ntainer#0-0-C-1] o.a.k.c.c.internals.AbstractCoordinator : Successfully joined group 0 with generation 6
2019-01-01 13:48:00.960 INFO 1422 --- [ntainer#0-0-C-1] o.a.k.c.c.internals.ConsumerCoordinator : Setting newly assigned partitions [topic001-1] for group 0
2019-01-01 13:48:00.967 INFO 1422 --- [ntainer#0-0-C-1] o.s.k.l.KafkaMessageListenerContainer : partitions assigned:[topic001-1]
验证消息的生产和消费
1.在浏览器输入以下地址：192.168.1.102:8080/send/Tom/hello
2.浏览器显示返回的结果是：send message to [Tom] success (2019-01-01 13:58:08)，表示操作成功；
3.去检查两个消费者进程的控制台，发现其中一个成功的消费了消息，如下：
----------------- record =ConsumerRecord(topic = topic001, partition = 0, offset = 0, CreateTime = 1546351226016, serialized key size = -1, serialized value size = 133, headers = RecordHeaders(headers = [], isReadOnly = false), key = null, value = {"timeLong":1546351225804,"name":"Tom","bizID":"4f1b6cf6-78d4-455d-b530-3956723a074f","time":"2019-01-01 22:00:25","message":"hello"})
------------------ message ={"timeLong":1546351225804,"name":"Tom","bizID":"4f1b6cf6-78d4-455d-b530-3956723a074f","time":"2019-01-01 22:00:25","message":"hello"}
至此，外部应用使用基于Docker的kafa服务实战就完成了，如果您也在用Docker部署kafka服务，给外部应用使用，希望本文能给您提供一些参考；
文章来源：https://blog.csdn.net/boling_cavalry/article/details/85528519
推荐阅读：https://www.roncoo.com/search/docker
