大数据之eureka 服务注册限流 并发控制 / 流量保护 实践

大数据阿木 发布于 9 天前 1 次阅读

摘要：

在分布式系统中，服务注册与发现是核心功能之一。Eureka作为Netflix开源的服务发现工具，在微服务架构中扮演着重要角色。随着服务数量的增加和访问量的提升，服务注册中心的稳定性成为关键问题。本文将围绕Eureka服务注册限流，探讨并发控制与流量保护实践，以保障服务注册中心的稳定运行。

一、

Eureka服务注册中心在微服务架构中负责服务实例的注册与发现。当服务实例启动时，它会向Eureka注册中心注册自己的信息；当服务实例停止时，它会注销自己的信息。在这个过程中，如果并发控制不当或流量过大，可能会导致服务注册中心崩溃，影响整个系统的稳定性。对Eureka服务注册进行限流和并发控制至关重要。

二、Eureka服务注册限流原理

1. 限流算法

Eureka服务注册限流主要采用令牌桶算法（Token Bucket）和漏桶算法（Leaky Bucket）两种算法。令牌桶算法允许一定数量的请求通过，而漏桶算法则保证请求以恒定的速率通过。

2. 限流策略

（1）固定窗口限流：在固定时间窗口内，只允许一定数量的请求通过。

（2）滑动窗口限流：在滑动时间窗口内，只允许一定数量的请求通过。

（3）令牌桶限流：根据令牌桶算法，控制请求通过速率。

（4）漏桶限流：根据漏桶算法，保证请求以恒定速率通过。

三、Eureka服务注册限流实践

1. 代码实现

以下是一个基于固定窗口限流的Eureka服务注册限流示例：

java
import com.netflix.appinfo.InstanceInfo;

import com.netflix.discovery.EurekaClient;

import com.netflix.discovery.shared.transport.EurekaTransportClient;

import com.netflix.discovery.shared.transport.jersey.JerseyEurekaHttpClient;

import org.glassfish.jersey.client.ClientConfig;

import org.glassfish.jersey.client.JerseyClientBuilder;



import javax.ws.rs.client.Client;

import javax.ws.rs.client.WebTarget;

import javax.ws.rs.core.MediaType;

import java.util.concurrent.ConcurrentHashMap;

import java.util.concurrent.atomic.AtomicInteger;



public class EurekaClientWithRateLimiting implements EurekaClient {

    private final EurekaClient delegate;

    private final ConcurrentHashMap<String, AtomicInteger> requestCountMap = new ConcurrentHashMap<>();

    private final int maxRequestsPerSecond;



public EurekaClientWithRateLimiting(EurekaClient delegate, int maxRequestsPerSecond) {

        this.delegate = delegate;

        this.maxRequestsPerSecond = maxRequestsPerSecond;

    }



@Override

    public void registerInstance(InstanceInfo instanceInfo) {

        if (canRegisterInstance()) {

            delegate.registerInstance(instanceInfo);

        }

    }



@Override

    public void unregisterInstance(String appName, String id) {

        delegate.unregisterInstance(appName, id);

    }



@Override

    public List<InstanceInfo> getInstancesByAppId(String appName) {

        return delegate.getInstancesByAppId(appName);

    }



@Override

    public void cancelHeartbeat(String appName, String id) {

        delegate.cancelHeartbeat(appName, id);

    }



@Override

    public void renewInstanceInstanceInfo(InstanceInfo instanceInfo) {

        delegate.renewInstanceInstanceInfo(instanceInfo);

    }



@Override

    public List<String> getApplications() {

        return delegate.getApplications();

    }



@Override

    public ApplicationInfo getApplicationInfoByName(String appName) {

        return delegate.getApplicationInfoByName(appName);

    }



@Override

    public void addInstanceInfo(InstanceInfo instanceInfo) {

        delegate.addInstanceInfo(instanceInfo);

    }



@Override

    public void removeInstanceInfo(InstanceInfo instanceInfo) {

        delegate.removeInstanceInfo(instanceInfo);

    }



@Override

    public void setTransportClient(EurekaTransportClient transportClient) {

        delegate.setTransportClient(transportClient);

    }



@Override

    public EurekaTransportClient getTransportClient() {

        return delegate.getTransportClient();

    }



private boolean canRegisterInstance() {

        String appName = delegate.getApplicationInfoByName("myApp").getAppName();

        AtomicInteger requestCount = requestCountMap.computeIfAbsent(appName, k -> new AtomicInteger(0));

        if (requestCount.incrementAndGet() <= maxRequestsPerSecond) {

            requestCount.decrementAndGet();

            return true;

        }

        return false;

    }

}

2. 配置Eureka客户端

在Spring Boot项目中，可以通过以下方式配置Eureka客户端：

java
import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import com.netflix.appinfo.InstanceInfo;

import com.netflix.discovery.EurekaClient;

import com.netflix.discovery.EurekaClientConfigBean;

import com.netflix.discovery.converters.JsonInstanceInfoConverter;

import com.netflix.discovery.converters.JsonInstanceStatusConverter;

import com.netflix.discovery.converters.JsonRepresentationConverter;

import com.netflix.discovery.converters.StringToInstanceStatusConverter;

import com.netflix.discovery.converters.StringToVersionedResponseConverter;

import com.netflix.discovery.converters.jackson.JacksonJsonInstanceInfoConverter;

import com.netflix.discovery.converters.jackson.JacksonJsonInstanceStatusConverter;

import com.netflix.discovery.converters.jackson.JacksonJsonRepresentationConverter;

import com.netflix.discovery.converters.jackson.StringToJacksonInstanceStatusConverter;

import com.netflix.discovery.converters.jackson.StringToJacksonVersionedResponseConverter;



@Configuration

public class EurekaClientConfig {



@Bean

    public EurekaClient eurekaClient(EurekaClientConfigBean clientConfigBean) {

        return new EurekaClientWithRateLimiting(clientConfigBean.getClient(), 100);

    }

}

四、流量保护实践

1. 代码实现

以下是一个基于漏桶算法的流量保护示例：

java
import com.netflix.appinfo.InstanceInfo;

import com.netflix.discovery.EurekaClient;

import com.netflix.discovery.shared.transport.EurekaTransportClient;

import com.netflix.discovery.shared.transport.jersey.JerseyEurekaHttpClient;

import org.glassfish.jersey.client.ClientConfig;

import org.glassfish.jersey.client.JerseyClientBuilder;



import javax.ws.rs.client.Client;

import javax.ws.rs.client.WebTarget;

import javax.ws.rs.core.MediaType;

import java.util.concurrent.ConcurrentHashMap;

import java.util.concurrent.atomic.AtomicInteger;



public class EurekaClientWithTrafficShaping implements EurekaClient {

    private final EurekaClient delegate;

    private final ConcurrentHashMap<String, AtomicInteger> requestCountMap = new ConcurrentHashMap<>();

    private final int maxRequestsPerSecond;

    private final int leakRate;



public EurekaClientWithTrafficShaping(EurekaClient delegate, int maxRequestsPerSecond, int leakRate) {

        this.delegate = delegate;

        this.maxRequestsPerSecond = maxRequestsPerSecond;

        this.leakRate = leakRate;

    }



@Override

    public void registerInstance(InstanceInfo instanceInfo) {

        if (canRegisterInstance()) {

            delegate.registerInstance(instanceInfo);

        }

    }



@Override

    // ... 其他方法与EurekaClientWithRateLimiting相同 ...



private boolean canRegisterInstance() {

        String appName = delegate.getApplicationInfoByName("myApp").getAppName();

        AtomicInteger requestCount = requestCountMap.computeIfAbsent(appName, k -> new AtomicInteger(0));

        if (requestCount.incrementAndGet() <= maxRequestsPerSecond) {

            requestCount.decrementAndGet();

            return true;

        }

        if (requestCount.get() > maxRequestsPerSecond) {

            int leakedRequests = requestCount.get() - maxRequestsPerSecond;

            requestCount.set(maxRequestsPerSecond);

            if (leakedRequests <= leakRate) {

                requestCount.addAndGet(-leakedRequests);

                return true;

            }

        }

        return false;

    }

}

2. 配置Eureka客户端

在Spring Boot项目中，可以通过以下方式配置Eureka客户端：

java
import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import com.netflix.appinfo.InstanceInfo;

import com.netflix.discovery.EurekaClient;

import com.netflix.discovery.EurekaClientConfigBean;

import com.netflix.discovery.converters.JsonInstanceInfoConverter;

import com.netflix.discovery.converters.JsonInstanceStatusConverter;

import com.netflix.discovery.converters.JsonRepresentationConverter;

import com.netflix.discovery.converters.StringToInstanceStatusConverter;

import com.netflix.discovery.converters.StringToVersionedResponseConverter;

import com.netflix.discovery.converters.jackson.JacksonJsonInstanceInfoConverter;

import com.netflix.discovery.converters.jackson.JacksonJsonInstanceStatusConverter;

import com.netflix.discovery.converters.jackson.JacksonJsonRepresentationConverter;

import com.netflix.discovery.converters.jackson.StringToJacksonInstanceStatusConverter;

import com.netflix.discovery.converters.jackson.StringToJacksonVersionedResponseConverter;



@Configuration

public class EurekaClientConfig {



@Bean

    public EurekaClient eurekaClient(EurekaClientConfigBean clientConfigBean) {

        return new EurekaClientWithTrafficShaping(clientConfigBean.getClient(), 100, 10);

    }

}

五、总结

本文介绍了Eureka服务注册限流和流量保护的实践。通过实现自定义的Eureka客户端，我们可以对服务注册进行限流和流量保护，从而提高服务注册中心的稳定性和可用性。在实际应用中，可以根据具体需求调整限流策略和流量保护参数，以达到最佳效果。