Spring Cloud Eureka：服务注册与发现

Spring Cloud Eureka是Spring Cloud生态系统中的一个组件，它是用于实现服务注册与发现的服务治理组件。在微服务架构中，服务之间存在复杂的依赖关系，而Spring Cloud Eureka可以帮助解决服务之间相互查找和通信的问题

Eureka简介

Eureka是Netflix开源的服务发现组件，用于在分布式系统中实现服务注册与发现。它是Netflix公司在构建微服务架构时开发的核心组件之一，后来成为了Spring Cloud生态系统中的一部分

Eureka注册中心搭建

Eureka服务端搭建

eureka-server依赖导入

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>

启动类添加注解@EnableEurekaServer

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

配置文件application.yml配置

server:
  port: 8001 #指定运行端口
spring:
  application:
    name: eureka-server #指定服务名称
eureka:
  instance:
    hostname: localhost #指定主机地址
  client:
    fetch-registry: false #指定是否要从注册中心获取服务（注册中心不需要开启）
    register-with-eureka: false #指定是否要注册到注册中心（注册中心不需要开启）
  server:
    enable-self-preservation: false #关闭保护模式

Eureka客户端搭建

eureka-client依赖导入

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

启动类添加注解@EnableDiscoveryClient

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

配置文件application.yml配置

server:
  port: 8101 #运行端口号
spring:
  application:
    name: eureka-client #服务名称
eureka:
  client:
    register-with-eureka: true #注册到Eureka的注册中心
    fetch-registry: true #获取注册实例列表
    service-url:
      defaultZone: http://localhost:8001/eureka/ #配置注册中心地址

Eureka集群搭建

eureka-sever添加配置文件application-replica1.yml配置第一个注册中心

server:
  port: 8002
spring:
  application:
    name: eureka-server
eureka:
  instance:
    hostname: replica1
  client:
    serviceUrl:
      defaultZone: http://replica2:8003/eureka/ #注册到另一个Eureka注册中心
    fetch-registry: true
    register-with-eureka: true

给eureka-sever添加配置文件application-replica2.yml配置第二个注册中心

server:
  port: 8003
spring:
  application:
    name: eureka-server
eureka:
  instance:
    hostname: replica2
  client:
    serviceUrl:
      defaultZone: http://replica1:8002/eureka/ #注册到另一个Eureka注册中心
    fetch-registry: true
    register-with-eureka: true

修改Eureka-client，连接到集群

server:
  port: 8102
spring:
  application:
    name: eureka-client
eureka:
  client:
    register-with-eureka: true
    fetch-registry: true
    service-url:
      defaultZone: http://replica1:8002/eureka/,http://replica2:8003/eureka/ #同时注册到两个注册中心

Eureka添加认证

添加SpringSecurity依赖
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-security</artifactId>
</dependency>
添加application.yml配置文件（配置用户名、密码）
server:
  port: 8004
spring:
  application:
    name: eureka-security-server
  security: #配置SpringSecurity登录用户名和密码
    user:
      name: macro
      password: 123456
eureka:
  instance:
    hostname: localhost
  client:
    fetch-registry: false
    register-with-eureka: false
添加 Java 配置WebSecurityConfig

默认情况下，Spring Security会开启CSRF（Cross-Site Request Forgery）保护，这是一种用于防止跨站点请求伪造攻击的安全机制。当你添加了Spring Security依赖到应用程序中时，每个POST、PUT、DELETE等修改类请求都需要在请求头中包含CSRF token才能被服务器接受

默认情况下添加SpringSecurity依赖的应用每个请求都需要添加CSRF token才能访问，Eureka客户端注册时并不会添加，所以需要配置/eureka/**路径不需要CSRF token
@EnableWebSecurity
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.csrf().ignoringAntMatchers("/eureka/**");
        super.configure(http);
    }
}