微服务注册中心:Consul——服务注册
系列文章:
微服务网关:Spring Cloud Gateway —— Zuul
微服务网关:Spring Cloud Config- 配置中心
一 简介
微服务注册中心:Consul——概念与基础操作介绍了 consul 的安装和基本操作,本篇开始在 consul 上进行服务注册与发现,语言使用 Java,框架使用 Spring Boot 整合 Consul。
二 Spring Boot 整合 Consul
通常 demo 比较好找,导入后观察需要引入哪些依赖,然后启动。最多微调版本和配置问题即可。
2.1 网上 demo
打脸来的如此迅速,百度上搜了一堆,最后发现都是官方文档的翻译,版本不清,代码不全,尝试几个未果。再次感叹现在很多文章的质量。
2.2 官方文档
不得已还是先尝试查看官方文档,Spring Cloud Consul是基于 3.0.2 版本,给出的集成 demo。不过很遗憾,官方给出的 sample 地址,访问一直是 404 状态。
上面 Consul Sample 的查看结果:
2.3 spring-cloud 的 github
考虑下一种渠道,寻找官方github。官方的 pom.xml 配置建议如下:
<project>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>{spring-boot-version}</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-consul-discovery</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
事实上,springboot 的版本选择过程中也遇到不少问题,几个典型的错误如下(为了节省空间,只截取了关键错误信息):
2.3.1 启动报错信息 1
Description:
An attempt was made to call a method that does not exist. The attempt was made from the following location:
org.springframework.cloud.client.discovery.health.DiscoveryCompositeHealthIndicator.<init>(DiscoveryCompositeHealthIndicator.java:41)
The following method did not exist:
org.springframework.boot.actuate.health.CompositeHealthIndicator.<init>(Lorg/springframework/boot/actuate/health/HealthAggregator;)V
The method's class, org.springframework.boot.actuate.health.CompositeHealthIndicator, is available from the following locations:
jar:file:/Users/lijingyong/.m2/repository/org/springframework/boot/spring-boot-actuator/2.2.6.RELEASE/spring-boot-actuator-2.2.6.RELEASE.jar!/org/springframework/boot/actuate/health/CompositeHealthIndicator.class
It was loaded from the following location:
file:/Users/lijingyong/.m2/repository/org/springframework/boot/spring-boot-actuator/2.2.6.RELEASE/spring-boot-actuator-2.2.6.RELEASE.jar
Action:
Correct the classpath of your application so that it contains a single, compatible version of org.springframework.boot.actuate.health.CompositeHealthIndicator
Process finished with exit code 1
2.3.2 报错 2
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.cloud.consul.serviceregistry.ConsulAutoRegistration]: Factory method 'consulRegistration' threw exception; nested exception is java.lang.IllegalArgumentException: Consul service ids must not be empty, must start with a letter, end with a letter or digit, and have as interior characters only letters, digits, and hyphen: null
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:185) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
at org.springframework.beans.factory.support.ConstructorResolver.instantiate(ConstructorResolver.java:651) ~[spring-beans-5.2.5.RELEASE.jar:5.2.5.RELEASE]
... 96 common frames omitted
Caused by: java.lang.IllegalArgumentException: Consul service ids must not be empty, must start with a letter, end with a letter or digit, and have as interior characters only letters, digits, and hyphen: null
at org.springframework.cloud.consul.serviceregistry.ConsulAutoRegistration.normalizeForDns(ConsulAutoRegistration.java:178) ~[spring-cloud-consul-discovery-2.2.1.RELEASE.jar:2.2.1.RELEASE]
2.4 一个可用 demo
根据官方说明,并参考另一个 demo:https://github.com/RobbieXie/springboot-consul 后,整理如下,不过是使用的较旧版本 springboot,可以根据需要更新到适合的版本信息。
关键配置和代码:
2.4.1 pom.xml
<?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>
<groupId>org.example</groupId>
<artifactId>springboot-consul</artifactId>
<description>Spring Boot整合consul示例</description>
<version>1.0-SNAPSHOT</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.9.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<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-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.orbitz.consul</groupId>
<artifactId>consul-client</artifactId>
<version>1.0.0</version>
</dependency>
<dependency>
<groupId>com.ecwid.consul</groupId>
<artifactId>consul-api</artifactId>
<version>1.3.0</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<snapshots>
<enabled>false</enabled>
</snapshots>
<id>central</id>
<name>bintray</name>
<url>http://jcenter.bintray.com</url>
</repository>
</repositories>
</project>
2.4.2 应用启动类 SpringBootConsulApplication
package com.flamingskys.learn.springboot.consul;
import com.flamingskys.learn.springboot.consul.service.ConsulService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import javax.annotation.PreDestroy;
@SpringBootApplication
@EnableAutoConfiguration
public class SpringBootConsulApplication {
@Value("${consul.instanceId}")
private String instanceId;
@Bean
public String getInstanceId(){
return instanceId;
}
@Autowired
private ConsulService consulService;
public static void main(String[] args) {
SpringApplication.run(SpringBootConsulApplication.class, args);
}
@PreDestroy
public void beforeExit(){
System.out.println("-----------------------------BEFORE EXIT--------------------------------");
consulService.deregisterService(instanceId);
}
}
2.4.3 资源配置 application.properties
spring.application.name=first-consul-client
consul.host=127.0.0.1
consul.port=8500
consul.instanceId=${spring.application.name}:${spring.application.instanceid:${random.value}}
spring.cloud.consul.discovery.heartbeat.enabled=true
应用启动后,查看 console 上注册的服务列表,first-consul-client 就是我们的服务:
完整代码已上传到了gitee。可关注公众号:程序员架构进阶 随时获取更新。
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原文链接:【http://xie.infoq.cn/article/958de779686fa98c3ac22c5b5】。文章转载请联系作者。
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