Ribbon核心原理与架构深度详解

[Client Application]
       ↓
[Ribbon Client]
       ↓
[Load Balancer] → [Server List Filter] → [Rule] → [Ping]
       ↓
[HTTP/TCP Client]

// 伪代码流程
public Response execute(Request request) {
    // 1. 通过Rule选择实例
    Server server = loadBalancer.chooseServer(); 
    // 2. 构造请求
    LBRequest lbRequest = buildRequest(request, server);
    // 3. 执行请求（支持重试机制）
    return client.execute(lbRequest); 
}

# 全局配置
service-name:
  ribbon:
    NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule
# 或通过注解指定
@RibbonClient(name = "service-name", 
              configuration = CustomConfig.class)

public class CustomRule extends AbstractLoadBalancerRule {
    @Override
    public Server choose(Object key) {
        // 实现自定义选择逻辑
        List<Server> servers = lb.getAllServers();
        return servers.get(0); // 示例：总是选第一个
    }
}

# 最大重试次数（不包括首次请求）
service-name.ribbon.MaxAutoRetries=1
# 切换实例的重试次数
service-name.ribbon.MaxAutoRetriesNextServer=1
# 是否所有操作都重试
service-name.ribbon.OkToRetryOnAllOperations=true

ribbon:
  ReadTimeout: 5000   # 请求超时(ms)
  ConnectTimeout: 2000 # 连接超时(ms)
  eager-load:
    enabled: true     # 启动时立即加载
    clients: service-a,service-b

// 自定义配置类
@Configuration
public class MyRibbonConfig {
    @Bean
    public IRule ribbonRule() {
        return new RandomRule(); // 替换默认策略
    }
    @Bean
    public IPing ribbonPing() {
        return new PingUrl(); // 主动健康检查
    }
}