SpringBoot3下Spring Cloud Config Server无法注册到Eureka的认证问题

在Spring Boot 3.0.0、Spring Cloud 2022.0.0-RC2环境中，Spring Cloud Config Server无法注册到开启用户名密码认证的Eureka注册中心。已在Config Server的eureka.client.serviceUrl.defaultZone中配置带认证信息的地址，但启动时控制台报错AuthScheme is null，且无法发送心跳。相同代码在Spring Boot 2.6版本可正常运行。

相关配置及报错日志如下：

Eureka Server 配置（application.yml） #

server:
  port: 8761

spring:
  application:
    name: eureka-server
  profiles:
    active: dev
  security:
    user:
      name: user
      password: password
 
eureka:
  instance:
    instance-id: ${spring.application.name}:${random.uuid}
  client:
    serviceUrl:
      defaultZone: ${EUREKA_SERVER:http://user:password@localhost:8761/eureka}
    lease-renewal-interval-in-seconds: 5
    registerWithEureka: true
    fetchRegistry: false

management:
  endpoints:
    web:
      exposure:
        include: "*"

Config Server 配置（application.yml） #

server:
   port: 8888

management:
  endpoints:
    web:
      exposure:
        include: "*"
  endpoint:
    env:
      post:
        enabled: true

        
logging:
  level:
    com.netflix.discovery: 'DEBUG'
    org.springframework.cloud: 'DEBUG'
    
spring:
   application:
      name: config-server
   profiles:
    active: dev
   devtools:
    livereload:
      port: 35730
   jmx:
    enabled: true
   cloud:
         config:
            fail-fast: true
            discovery.enabled: true
            server:
              git:
                cloneOnStart: true
                uri:  ${GIT_CONFIG_REPOSITORY}
                skipSslValidation: true
                default-label: master
eureka:
   registerWithEureka: true
   fetchRegistry: true
   client:
      serviceUrl:
         defaultZone: ${EUREKA_SERVER:http://username:password@localhost:8761/eureka}
   instance:
         instance-id: ${spring.application.name}:${random.uuid}

报错日志 #

2022-12-11T15:15:50.152+01:00[0;39m [32m INFO[0;39m [35m15612[0;39m [2m---[0;39m [2m[           main][0;39m [36mc.n.d.s.t.d.RedirectingEurekaHttpClient [0;39m [2m:[0;39m Request execution error. endpoint=DefaultEndpoint{ serviceUrl='http://username:password@localhost:8761/eureka/}, exception=AuthScheme is null stacktrace=java.lang.IllegalStateException: AuthScheme is null
    at org.apache.hc.core5.util.Asserts.notNull(Asserts.java:56)
    ...（省略重复栈信息）
2022-12-11T15:16:20.204+01:00[0;39m [31mERROR[0;39m [35m15612[0;39m [2m---[0;39m [2m[tbeatExecutor-0][0;39m [36mcom.netflix.discovery.DiscoveryClient   [0;39m [2m:[0;39m DiscoveryClient_CONFIG-SERVER/config-server:b3790bfa-41c5-42ca-8e27-b70b219c0ab9 - was unable to send heartbeat!
com.netflix.discovery.shared.transport.TransportException: Cannot execute request on any known server
    ...（省略重复栈信息）

解决方案 #

1. 显式配置Eureka Client的认证信息

Spring Boot 3.x升级了Apache HttpClient到5.x版本，Netflix Eureka Client不再自动解析defaultZone URL中的用户名密码来生成认证方案（AuthScheme），需要单独配置认证信息：

修改Config Server的application.yml，移除defaultZone中的用户名密码，添加eureka.client.username和eureka.client.password：

eureka:
  registerWithEureka: true
  fetchRegistry: true
  client:
    serviceUrl:
      defaultZone: ${EUREKA_SERVER:http://localhost:8761/eureka}
    # 显式配置Eureka认证用户名和密码
    username: username
    password: password
  instance:
    instance-id: ${spring.application.name}:${random.uuid}

如果使用环境变量，可调整为：

eureka:
  client:
    serviceUrl:
      defaultZone: ${EUREKA_SERVER:http://localhost:8761/eureka}
    username: ${EUREKA_USER:username}
    password: ${EUREKA_PASS:password}

2. （可选）兼容URL方式的临时方案

若需保留URL中的认证信息，需手动配置HttpClient的AuthScheme，但这种方式不如显式配置规范，不推荐。可以通过自定义EurekaHttpClientFactory来实现，但步骤繁琐，优先推荐第一种方案。

原因说明 #

Spring Cloud 2022.0.0（Kilburn版本）基于Spring Boot 3.x，底层依赖的Apache HttpClient从4.x升级到5.x。Netflix Eureka Client在适配HttpClient5时，移除了自动解析URL中认证信息的逻辑，导致直接在defaultZone中携带username:password@的方式无法生成有效的AuthScheme，从而抛出AuthScheme is null异常。而Spring Boot 2.6版本使用的是HttpClient4.x，Eureka Client可以正常解析URL中的认证信息，因此旧版本代码可正常运行。

内容的提问来源于stack exchange，提问作者omar