SpringCloud根据cookie进行gateway路由

发表于 2023-10-31 分类于 Spring ， SpringCloud ， SpringCloudGateway 阅读次数：阅读次数：本文字数： 529 阅读时长 ≈ 2 分钟

01.01-根据 cookie 进行 gateway 路由

1. 设计

参与角色：gateway, service-provider

2. 实现

2.1 LoadBalancer 实现类，参照 RoundRibonLoadBalancer 实现。

功能：跟进前端的 cookie 中的 zone，来匹配 nacos 注册信息中 metadata(元数据）的 version。进行匹配。

其他完全根据 gateway 的路由完成。

package com.alibaba.cloud.examples.loadbalancer;

import com.alibaba.cloud.commons.lang.StringUtils;
import java.util.List;
import java.util.Random;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.Collectors;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.DefaultResponse;
import org.springframework.cloud.client.loadbalancer.EmptyResponse;
import org.springframework.cloud.client.loadbalancer.Request;
import org.springframework.cloud.client.loadbalancer.RequestDataContext;
import org.springframework.cloud.client.loadbalancer.Response;
import org.springframework.cloud.loadbalancer.core.NoopServiceInstanceListSupplier;
import org.springframework.cloud.loadbalancer.core.ReactorServiceInstanceLoadBalancer;
import org.springframework.cloud.loadbalancer.core.SelectedInstanceCallback;
import org.springframework.cloud.loadbalancer.core.ServiceInstanceListSupplier;
import reactor.core.publisher.Mono;

/**
 * @Title : MyLoadBalancer
 * @Description: :
 * @author: libo@juzishuke.com
 * @date: 2023/9/11 16:51
 * @Version:1.0
 */
//@Component
public class MyLoadBalancer implements ReactorServiceInstanceLoadBalancer {

    private static final Log log = LogFactory.getLog(MyLoadBalancer.class);

    final AtomicInteger position;
    final String        serviceId;
    ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider;

    public MyLoadBalancer(
            ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider,
            String name) {
        this(serviceInstanceListSupplierProvider, name, new Random().nextInt(1000));
    }

    public MyLoadBalancer(
            ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider,
            String name, int seedPosition) {
        this.serviceId = name;
        this.serviceInstanceListSupplierProvider = serviceInstanceListSupplierProvider;
        this.position = new AtomicInteger(seedPosition);
    }

    @Override
    public Mono<Response<ServiceInstance>> choose(Request request) {
        ServiceInstanceListSupplier supplier = serviceInstanceListSupplierProvider.getIfAvailable(
                NoopServiceInstanceListSupplier::new);
        return supplier.get(request).next()
                .map(serviceInstances -> processInstanceResponse(request, supplier,
                        serviceInstances));
    }

    private Response<ServiceInstance> processInstanceResponse(Request request,
            ServiceInstanceListSupplier supplier, List<ServiceInstance> serviceInstances) {
        String zone = ((RequestDataContext) request.getContext()).getClientRequest().getCookies()
                .getFirst("zone");
        if (StringUtils.isNotBlank(zone)) {
            serviceInstances = serviceInstances.stream()
                    .filter(e -> zone.equalsIgnoreCase(e.getMetadata().get("version"))).collect(Collectors.toList());
        }
        Response<ServiceInstance> serviceInstanceResponse = getInstanceResponse(request,
                serviceInstances);
        if (supplier instanceof SelectedInstanceCallback && serviceInstanceResponse.hasServer()) {
            ((SelectedInstanceCallback) supplier).selectedServiceInstance(
                    serviceInstanceResponse.getServer());
        }
        return serviceInstanceResponse;
    }

    private Response<ServiceInstance> getInstanceResponse(Request request,
            List<ServiceInstance> instances) {
        if (instances.isEmpty()) {
            if (log.isWarnEnabled()) {
                log.warn("No servers available for service: " + serviceId);
            }
            return new EmptyResponse();
        }

        // Do not move position when there is only 1 instance, especially some suppliers
        // have already filtered instances
        if (instances.size() == 1) {
            return new DefaultResponse(instances.get(0));
        }

        // Ignore the sign bit, this allows pos to loop sequentially from 0 to
        // Integer.MAX_VALUE
        int pos = this.position.incrementAndGet() & Integer.MAX_VALUE;

        ServiceInstance instance = instances.get(pos % instances.size());

        return new DefaultResponse(instance);
    }
}

2.2 LoadBalancerConfiguration 配置类

package com.alibaba.cloud.examples.config;

import com.alibaba.cloud.examples.loadbalancer.MyLoadBalancer;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.loadbalancer.core.ReactorLoadBalancer;
import org.springframework.cloud.loadbalancer.core.ServiceInstanceListSupplier;
import org.springframework.cloud.loadbalancer.support.LoadBalancerClientFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.env.Environment;

/**
 * @Title : LoadBalancerConfiguration
 * @Description: :
 * @author: libo@juzishuke.com
 * @date: 2023/9/11 17:16
 * @Version:1.0
 */
@Configuration(proxyBeanMethods = false)
public class LoadBalancerConfiguration {


    @Bean
    public ReactorLoadBalancer<ServiceInstance> reactorServiceInstanceLoadBalancer(
            Environment environment, LoadBalancerClientFactory loadBalancerClientFactory) {
        String name = environment.getProperty(LoadBalancerClientFactory.PROPERTY_NAME);
        return new MyLoadBalancer(
                loadBalancerClientFactory.getLazyProvider(name, ServiceInstanceListSupplier.class),
                name);
    }
}