springcloud按版本发布微服务达到不停机更新的效果

本文基于以下环境完成

• spring-boot 2.3.2.RELEASE
• spring-cloud Hoxton.SR9
• spring-cloud-alibaba 2.2.6.RELEASE
• spring-cloud-starter-gateway 2.2.6.RELEASE
• spring-cloud-starter-loadbalancer 2.2.6.RELEASE
• nacos 2.0.3

一、思路

实现思路：
前端项目在请求后端接口时，携带一个版本号version，网关gateway在接收到这个version后，根据version的值去选择对应的微服务实例，服务之间的调用openfeign也通过版本号去选择对应的服务实例

举例：
每次更新项目时版本号递增，比如目前在使用的后端项目版本为1.0.0，那么前端携带的版本也是1.0.0,
当我们要更新项目时，后端新的版本为2.0.0 前端项目的版本也为2.0.0，如果用户没有刷新页面，那么还是携带旧的版本号1.0.0, 那么请求都会转发到后端1.0.0, 如果用户刷新页面，那么就会携带新版本号2.0.0，此时请求被转发后端2.0.0版本

实现方式：
排除自带的ribbon依赖

<exclusions>
    <exclusion>
        <groupId>org.springframework.cloud</groupId>
    </exclusion>
</exclusions>

引入spring-cloud-loadbalancer依赖

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-loadbalancer</artifactId>
    <version>2.2.6.RELEASE</version>
</dependency>

spring-cloud-loadbalancer文档地址：点我跳转

配置微服务版本号

spring:
  cloud:
    nacos:
      discovery:
        metadata:
          version: 2.0.0

后续可以在nacos中修改

二 、重写网关的负载策略

2.1 重写轮训负载均衡

spring-cloud-loadbalancer默认的负载策略是轮训，实现类为org.springframework.cloud.loadbalancer.core.RoundRobinLoadBalancer，我们主要看里面的choose和getInstanceResponse方法，在getInstanceResponse方法中传入ServiceInstance集合，然后从这个集合中选择一个合适的instance实例，那么我们只要在重写这个方法在里面添加版本的筛选
那么我们再看一下这个类是如何实例化的，主要是org.springframework.cloud.loadbalancer.annotation.LoadBalancerClientConfiguration

注意@ConditionalOnMissingBean这个注解，只有当spring容器中没有ReactorLoadBalancer类型的bean时才会实例化。

我们新建一个VersionLoadBalancer类，跟RoundRobinLoadBalancer一样去实现ReactorServiceInstanceLoadBalancer接口(其实就是把他的代码copy过来，然后添加我们自定义的筛选条件)

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.cloud.loadbalancer.core.*;
import org.springframework.http.HttpHeaders;
import org.springframework.util.StringUtils;
import reactor.core.publisher.Mono;

import org.springframework.beans.factory.ObjectProvider;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.reactive.DefaultResponse;
import org.springframework.cloud.client.loadbalancer.reactive.EmptyResponse;
import org.springframework.cloud.client.loadbalancer.reactive.Request;
import org.springframework.cloud.client.loadbalancer.reactive.Response;

/**
 * {@link org.springframework.cloud.loadbalancer.core.RoundRobinLoadBalancer}
 *
 * @Author 
 * @Date 2024/4/18 11:46
 * @Description
 **/
public class VersionLoadBalancer implements ReactorServiceInstanceLoadBalancer {

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

    private final AtomicInteger position;

    @Deprecated
    private ObjectProvider<ServiceInstanceSupplier> serviceInstanceSupplier;

    private ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider;

    private final String serviceId;

    /**
     * @param serviceId               id of the service for which to choose an instance
     * @param serviceInstanceSupplier a provider of {@link ServiceInstanceSupplier} that
     *                                will be used to get available instances
     * @deprecated Use {@link #VersionLoadBalancer(ObjectProvider, String)}} instead.
     */
    @Deprecated
    public VersionLoadBalancer(String serviceId,
                               ObjectProvider<ServiceInstanceSupplier> serviceInstanceSupplier) {
        this(serviceId, serviceInstanceSupplier, new Random().nextInt(1000));
    }

    /**
     * @param serviceInstanceListSupplierProvider a provider of
     *                                            {@link ServiceInstanceListSupplier} that will be used to get available instances
     * @param serviceId                           id of the service for which to choose an instance
     */
    public VersionLoadBalancer(
            ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider,
            String serviceId) {
        this(serviceInstanceListSupplierProvider, serviceId, new Random().nextInt(1000));
    }

    /**
     * @param serviceInstanceListSupplierProvider a provider of
     *                                            {@link ServiceInstanceListSupplier} that will be used to get available instances
     * @param serviceId                           id of the service for which to choose an instance
     * @param seedPosition                        Round Robin element position marker
     */
    public VersionLoadBalancer(
            ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider,
            String serviceId, int seedPosition) {
        this.serviceId = serviceId;
        this.serviceInstanceListSupplierProvider = serviceInstanceListSupplierProvider;
        this.position = new AtomicInteger(seedPosition);
    }

    /**
     * @param serviceId               id of the service for which to choose an instance
     * @param serviceInstanceSupplier a provider of {@link ServiceInstanceSupplier} that
     *                                will be used to get available instances
     * @param seedPosition            Round Robin element position marker
     * @deprecated Use {@link #VersionLoadBalancer(ObjectProvider, String, int)}}
     * instead.
     */
    @Deprecated
    public VersionLoadBalancer(String serviceId,
                               ObjectProvider<ServiceInstanceSupplier> serviceInstanceSupplier,
                               int seedPosition) {
        this.serviceId = serviceId;
        this.serviceInstanceSupplier = serviceInstanceSupplier;
        this.position = new AtomicInteger(seedPosition);
    }

    @SuppressWarnings("all")
    @Override
    // see original
    // https://github.com/Netflix/ocelli/blob/master/ocelli-core/
    // src/main/java/netflix/ocelli/loadbalancer/RoundRobinLoadBalancer.java
    public Mono<Response<ServiceInstance>> choose(Request request) {
        HttpHeaders headers = (HttpHeaders) request.getContext();
        String requestVersion = headers.getFirst("version");
        // TODO: move supplier to Request?
        // Temporary conditional logic till deprecated members are removed.
        if (serviceInstanceListSupplierProvider != null) {
            ServiceInstanceListSupplier supplier = serviceInstanceListSupplierProvider
                    .getIfAvailable(NoopServiceInstanceListSupplier::new);
            return supplier.get().next().map(m -> this.getInstanceResponse(m, requestVersion));
        }
        ServiceInstanceSupplier supplier = this.serviceInstanceSupplier
                .getIfAvailable(NoopServiceInstanceSupplier::new);
        return supplier.get().collectList().map(m -> this.getInstanceResponse(m, requestVersion));
    }

    @SuppressWarnings("deprecation")
    private Response<ServiceInstance> getInstanceResponse(
            List<ServiceInstance> instances, String requestVersion) {
        List<ServiceInstance> serviceInstances = this.filterInstance(instances, requestVersion);
        if (serviceInstances.isEmpty()) {
            log.warn("No servers available for service: " + this.serviceId + " ,request version: " + requestVersion);
            return new EmptyResponse();
        }
        // TODO: enforce order?
        int pos = Math.abs(this.position.incrementAndGet());

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

        return new DefaultResponse(instance);
    }

    /**
     * 获取对应的版本
     *
     * @param instances
     * @param requestVersion
     * @return
     */
    private List<ServiceInstance> filterInstance(List<ServiceInstance> instances, String requestVersion) {
        if (StringUtils.isEmpty(requestVersion)) {
            return instances;
        }
        return instances.stream().filter(f -> requestVersion.equals(f.getMetadata().get("version"))).collect(Collectors.toList());
    }

}

然后新建一个配置类VersionLoadBalancerConfig，注意不能使用@Configuration

import com.demo.gateway.filter.VersionLoadBalancer;
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.core.env.Environment;

/**
 * 注意: 这里不能使用@Configuration !!!
 * 参考 {@link org.springframework.cloud.loadbalancer.annotation.LoadBalancerClientConfiguration}
 *
 * @Author 
 * @Date 2024/4/18 11:50
 * @Description
 **/

public class VersionLoadBalancerConfig {

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

}

官方文档示例

然后在项目的启动类添加@LoadBalancerClients(defaultConfiguration = {VersionLoadBalancerConfig.class})

import com.demo.gateway.config.VersionLoadBalancerConfig;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.loadbalancer.annotation.LoadBalancerClients;

/**
 * @Author 
 * @Date 2022/10/10 16:38
 * @Description
 **/
@EnableDiscoveryClient
@SpringBootApplication
@LoadBalancerClients(defaultConfiguration = {VersionLoadBalancerConfig.class})
public class GatewayApplication {

    public static void main(String[] args) {
        SpringApplication.run(GatewayApplication.class, args);
    }

}

2.2 重写过滤器

此时运行项目发现碰到空指针异常，断点后发现是VersionLoadBalancer.choose方法里面request.getContext()是个null值，那么我们再看一下是在哪里调用了这个方法，主要是org.springframework.cloud.gateway.filter.ReactiveLoadBalancerClientFilter
那么我们需要重写这个过滤器，在choose方法里面将我们http请求的header对象传递给VersionLoadBalancer，我们再看一下ReactiveLoadBalancerClientFilter是怎么初始化的，主要是org.springframework.cloud.gateway.config.GatewayReactiveLoadBalancerClientAutoConfiguration

那么我们就可以新建一个VersionLoadBalancerFilter去覆盖原来的ReactiveLoadBalancerClientFilter(如果直接新增一个过滤器那么原来的过滤器也会执行，还会有过滤器的执行顺序问题)

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.LoadBalancerUriTools;
import org.springframework.cloud.client.loadbalancer.reactive.DefaultRequest;
import org.springframework.cloud.client.loadbalancer.reactive.Request;
import org.springframework.cloud.client.loadbalancer.reactive.Response;
import org.springframework.cloud.gateway.config.LoadBalancerProperties;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.cloud.gateway.filter.ReactiveLoadBalancerClientFilter;
import org.springframework.cloud.gateway.support.DelegatingServiceInstance;
import org.springframework.cloud.gateway.support.NotFoundException;
import org.springframework.cloud.gateway.support.ServerWebExchangeUtils;
import org.springframework.cloud.loadbalancer.core.ReactorLoadBalancer;
import org.springframework.cloud.loadbalancer.support.LoadBalancerClientFactory;
import org.springframework.core.Ordered;
import org.springframework.http.HttpHeaders;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import java.net.URI;

import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR;

/**
 * 参考 {@link ReactiveLoadBalancerClientFilter}
 * @Author SYLIANG
 * @Date 2024/4/19 10:48
 * @Description
 **/
public class VersionLoadBalancerFilter extends ReactiveLoadBalancerClientFilter implements GlobalFilter, Ordered {

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

    private static final int LOAD_BALANCER_CLIENT_FILTER_ORDER = 10250;

    private final LoadBalancerClientFactory clientFactory;

    private LoadBalancerProperties properties;

    public VersionLoadBalancerFilter(LoadBalancerClientFactory clientFactory, LoadBalancerProperties properties) {
        super(clientFactory, properties);
        this.clientFactory = clientFactory;
        this.properties = properties;
    }

    @Override
    public int getOrder() {
        return LOAD_BALANCER_CLIENT_FILTER_ORDER;
    }

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        URI url = (URI)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR);
        String schemePrefix = (String)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR);
        if (url != null && ("lb".equals(url.getScheme()) || "lb".equals(schemePrefix))) {
            ServerWebExchangeUtils.addOriginalRequestUrl(exchange, url);
            if (log.isTraceEnabled()) {
                log.trace(ReactiveLoadBalancerClientFilter.class.getSimpleName() + " url before: " + url);
            }

            return this.choose(exchange).doOnNext((response) -> {
                if (!response.hasServer()) {
                    throw NotFoundException.create(this.properties.isUse404(), "Unable to find instance for " + url.getHost());
                } else {
                    ServiceInstance retrievedInstance = (ServiceInstance)response.getServer();
                    URI uri = exchange.getRequest().getURI();
                    String overrideScheme = retrievedInstance.isSecure() ? "https" : "http";
                    if (schemePrefix != null) {
                        overrideScheme = url.getScheme();
                    }

                    DelegatingServiceInstance serviceInstance = new DelegatingServiceInstance(retrievedInstance, overrideScheme);
                    URI requestUrl = this.reconstructURI(serviceInstance, uri);
                    if (log.isTraceEnabled()) {
                        log.trace("LoadBalancerClientFilter url chosen: " + requestUrl);
                    }

                    exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR, requestUrl);
                }
            }).then(chain.filter(exchange));
        } else {
            return chain.filter(exchange);
        }
    }

    @Override
    protected URI reconstructURI(ServiceInstance serviceInstance, URI original) {
        return LoadBalancerUriTools.reconstructURI(serviceInstance, original);
    }

    @SuppressWarnings("deprecation")
    private Mono<Response<ServiceInstance>> choose(ServerWebExchange exchange) {
        URI uri = exchange.getAttribute(GATEWAY_REQUEST_URL_ATTR);
        ReactorLoadBalancer<ServiceInstance> loadBalancer = this.clientFactory
                .getInstance(uri.getHost(), VersionLoadBalancer.class);
        if (loadBalancer == null) {
            throw new NotFoundException("No loadbalancer available for " + uri.getHost());
        } else {
            return loadBalancer.choose(this.createRequest(exchange));
        }
    }

    @SuppressWarnings("deprecation")
    private Request createRequest(ServerWebExchange exchange) {
        HttpHeaders headers = exchange.getRequest().getHeaders();
        Request<HttpHeaders> request = new DefaultRequest<>(headers);
        return request;
    }
}

注意choose方法里面的ReactorLoadBalancer loadBalancer = this.clientFactory.getInstance(uri.getHost(), VersionLoadBalancer.class); 这里不能直接new，否则轮训会失效

新建配置类VersionFilterConfiguration

import com.personnel.gateway.filter.VersionLoadBalancerFilter;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
import org.springframework.boot.autoconfigure.AutoConfigureBefore;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.cloud.client.loadbalancer.reactive.ReactiveLoadBalancer;
import org.springframework.cloud.gateway.config.GatewayLoadBalancerClientAutoConfiguration;
import org.springframework.cloud.gateway.config.LoadBalancerProperties;
import org.springframework.cloud.gateway.filter.ReactiveLoadBalancerClientFilter;
import org.springframework.cloud.loadbalancer.config.LoadBalancerAutoConfiguration;
import org.springframework.cloud.loadbalancer.support.LoadBalancerClientFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.reactive.DispatcherHandler;

/**
 * ReactiveLoadBalancerClientFilter过滤器的Request没有请求头信息
 * 参考 {@link org.springframework.cloud.gateway.config.GatewayReactiveLoadBalancerClientAutoConfiguration}
 *
 * @Author 
 * @Date 2024/4/22 15:56
 * @Description
 **/
@Configuration(proxyBeanMethods = false)
@ConditionalOnClass({LoadBalancerClient.class, ReactiveLoadBalancer.class,
        LoadBalancerAutoConfiguration.class, DispatcherHandler.class})
@AutoConfigureBefore(GatewayLoadBalancerClientAutoConfiguration.class)
@AutoConfigureAfter(LoadBalancerAutoConfiguration.class)
@EnableConfigurationProperties(LoadBalancerProperties.class)
public class VersionFilterConfiguration {

    @Bean
    public ReactiveLoadBalancerClientFilter versionLoadBalancer(LoadBalancerClientFactory clientFactory,
                                                                LoadBalancerProperties properties) {
        return new VersionLoadBalancerFilter(clientFactory, properties);
    }

}

三、重写openfeign的负载策略

3.1 spring-cloud-loadbalancer负载

我们同样使用spring-cloud-loadbalancer作为负载均衡器，新建自定义负载策略VersionLoadBalancer类，注意这里面的版本号version通过spring-web的ServletRequestAttributes获取

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.reactive.DefaultResponse;
import org.springframework.cloud.client.loadbalancer.reactive.EmptyResponse;
import org.springframework.cloud.client.loadbalancer.reactive.Request;
import org.springframework.cloud.client.loadbalancer.reactive.Response;
import org.springframework.cloud.loadbalancer.core.*;
import org.springframework.http.HttpHeaders;
import org.springframework.util.StringUtils;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import reactor.core.publisher.Mono;

import java.util.List;
import java.util.Random;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.Collectors;

/**
 *
 * 重写负载均衡策略: 通过版本选择服务实例
 * {@link RoundRobinLoadBalancer}
 *
 * @Author 
 * @Date 2024/4/18 11:46
 * @Description
 **/
public class VersionLoadBalancer implements ReactorServiceInstanceLoadBalancer {

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

    private final AtomicInteger position;

    @Deprecated
    private ObjectProvider<ServiceInstanceSupplier> serviceInstanceSupplier;

    private ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider;

    private final String serviceId;

    private final String version = "version";

    /**
     * @param serviceId               id of the service for which to choose an instance
     * @param serviceInstanceSupplier a provider of {@link ServiceInstanceSupplier} that
     *                                will be used to get available instances
     * @deprecated Use {@link #VersionLoadBalancer(ObjectProvider, String)}} instead.
     */
    @Deprecated
    public VersionLoadBalancer(String serviceId,
                               ObjectProvider<ServiceInstanceSupplier> serviceInstanceSupplier) {
        this(serviceId, serviceInstanceSupplier, new Random().nextInt(1000));
    }

    /**
     * @param serviceInstanceListSupplierProvider a provider of
     *                                            {@link ServiceInstanceListSupplier} that will be used to get available instances
     * @param serviceId                           id of the service for which to choose an instance
     */
    public VersionLoadBalancer(
            ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider,
            String serviceId) {
        this(serviceInstanceListSupplierProvider, serviceId, new Random().nextInt(1000));
    }

    /**
     * @param serviceInstanceListSupplierProvider a provider of
     *                                            {@link ServiceInstanceListSupplier} that will be used to get available instances
     * @param serviceId                           id of the service for which to choose an instance
     * @param seedPosition                        Round Robin element position marker
     */
    public VersionLoadBalancer(
            ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider,
            String serviceId, int seedPosition) {
        this.serviceId = serviceId;
        this.serviceInstanceListSupplierProvider = serviceInstanceListSupplierProvider;
        this.position = new AtomicInteger(seedPosition);
    }

    /**
     * @param serviceId               id of the service for which to choose an instance
     * @param serviceInstanceSupplier a provider of {@link ServiceInstanceSupplier} that
     *                                will be used to get available instances
     * @param seedPosition            Round Robin element position marker
     * @deprecated Use {@link #VersionLoadBalancer(ObjectProvider, String, int)}}
     * instead.
     */
    @Deprecated
    public VersionLoadBalancer(String serviceId,
                               ObjectProvider<ServiceInstanceSupplier> serviceInstanceSupplier,
                               int seedPosition) {
        this.serviceId = serviceId;
        this.serviceInstanceSupplier = serviceInstanceSupplier;
        this.position = new AtomicInteger(seedPosition);
    }

    @SuppressWarnings("all")
    @Override
    // see original
    // https://github.com/Netflix/ocelli/blob/master/ocelli-core/
    // src/main/java/netflix/ocelli/loadbalancer/RoundRobinLoadBalancer.java
    public Mono<Response<ServiceInstance>> choose(Request request) {
        ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        String requestVersion = requestAttributes.getRequest().getHeader(version);
        // TODO: move supplier to Request?
        // Temporary conditional logic till deprecated members are removed.
        if (serviceInstanceListSupplierProvider != null) {
            ServiceInstanceListSupplier supplier = serviceInstanceListSupplierProvider
                    .getIfAvailable(NoopServiceInstanceListSupplier::new);
            return supplier.get().next().map(m -> this.getInstanceResponse(m, requestVersion));
        }
        ServiceInstanceSupplier supplier = this.serviceInstanceSupplier
                .getIfAvailable(NoopServiceInstanceSupplier::new);
        return supplier.get().collectList().map(m -> this.getInstanceResponse(m, requestVersion));
    }

    @SuppressWarnings("deprecation")
    private Response<ServiceInstance> getInstanceResponse(
            List<ServiceInstance> instances, String requestVersion) {
        List<ServiceInstance> serviceInstances = this.filterInstance(instances, requestVersion);
        if (serviceInstances.isEmpty()) {
            log.warn("No servers available for service: " + this.serviceId + " ,request version: " + requestVersion);
            return new EmptyResponse();
        }
        // TODO: enforce order?
        int pos = Math.abs(this.position.incrementAndGet());

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

        return new DefaultResponse(instance);
    }

    /**
     * 获取对应的版本
     *
     * @param instances
     * @param requestVersion
     * @return
     */
    private List<ServiceInstance> filterInstance(List<ServiceInstance> instances, String requestVersion) {
        if (StringUtils.isEmpty(requestVersion)) {
            return instances;
        }
        return instances.stream().filter(f -> requestVersion.equals(f.getMetadata().get(version))).collect(Collectors.toList());
    }

}

新建配置类VersionLoadBalancerConfig

import com.personnel.common.load.VersionLoadBalancer;
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.core.env.Environment;

/**
 * 注意: 这里不能使用@Configuration !!!
 * 参考 {@link org.springframework.cloud.loadbalancer.annotation.LoadBalancerClientConfiguration}
 *
 * @Author 
 * @Date 2024/4/18 11:50
 * @Description
 **/

public class VersionLoadBalancerConfig {

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

}

在启动类中添加@LoadBalancerClients(defaultConfiguration = {VersionLoadBalancerConfig.class})

3.2 ribbon负载

如果使用ribbon则使用以下配置

import com.alibaba.cloud.nacos.ribbon.NacosServer;
import com.google.common.base.Optional;
import com.netflix.loadbalancer.Server;
import com.netflix.loadbalancer.ZoneAvoidanceRule;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.stereotype.Component;
import org.springframework.util.CollectionUtils;
import org.springframework.util.StringUtils;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import java.util.ArrayList;
import java.util.List;

/**
 * openfeign调用根据版本选择对应的实例
 * @Author 
 * @Date 2024/1/18 14:16
 * @Description
 **/
@Component
public class VersionReleaseRule extends ZoneAvoidanceRule {

    private final String version = "version";

    @Override
    public Server choose(Object key) {
        ServletRequestAttributes requestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        String requestVersion = requestAttributes.getRequest().getHeader(version);
        if (!StringUtils.isEmpty(requestVersion)) {
            List<Server> serverList = this.getLoadBalancer().getAllServers();
            List<Server> versionServers = new ArrayList<>();
            for (Server server : serverList) {
                NacosServer nacosServer = (NacosServer) server;
                if (requestVersion.equals(nacosServer.getMetadata().get(version))) {
                    versionServers.add(server);
                }
            }
            if (!CollectionUtils.isEmpty(versionServers)) {
                Optional<Server> serverOptional = this.getPredicate().chooseRoundRobinAfterFiltering(versionServers, key);
                return serverOptional.isPresent() ? serverOptional.get() : null;
            }
        }
        return super.choose(key);
    }
}

四、openfeign携带token

在openfeign调用时如果没有携带token则添加以下配置

import feign.RequestInterceptor;
import feign.RequestTemplate;
import org.springframework.context.annotation.Bean;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

/**
 *  openfeign请求添加token
 * @Author SYLIANG
 * @Date 2024/4/25 11:22
 * @Description
 **/
@Configuration
public class FeignClientInterceptorConfig {

    private final String authorization = "Authorization";

    @Bean
    public RequestInterceptor requestInterceptor() {
        return new RequestInterceptor() {
            @Override
            public void apply(RequestTemplate requestTemplate) {
                // 从当前请求的 Header 中获取 token
                ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
                if (attributes != null) {
                    String token = attributes.getRequest().getHeader(authorization);
                    if (token != null && !token.isEmpty()) {
                        // 添加 token 到请求头部
                        requestTemplate.header(authorization, token);
                    }
                }
            }
        };
    }
}