springcloud + nacos多环境联调、本地联调（即灰度版本）

背景：

当我们使用nacos为注册中心注册微服务时，想本地环境和测试环境公用一个nacos，即注册中心等基础服务共用。当我们在服务A开发时，本地服务和测试环境服务都是注册到同一个nacos，由于nacos自带负载均衡策略，调用服务时就会使用负载均衡选择服务，导致我们无法正常调试接口。这时我们可以选择使用灰度版本来进行服务的选择。

废话不多说直接开干

首先声明一点我springcloud环境如下：

2.3.2.RELEASE

2.2.5.RELEASE

Hoxton.SR8

nacos版本是2.1.4，

具体实现步骤如下：

1、我们在配置文件中添加版本头（开发环境版本dev，我本地环境设置xf）

spring.cloud.nacos.discovery.metadata.VERSION=xf

2、添加灰度服务接口

/**

* @author xf

* @Title:

* @Description:

* @date 2023/1/12 17:17

*/

public interface GrayLoadBalancer {

/**

* 根据serviceId 筛选可用服务

* @param serviceId 服务ID

* @param request 当前请求

* @param exchange 请求不到目标实例时，走(父级)默认逻辑所需的参数

* @param clientFactory 请求不到目标实例时，走(父级)默认逻辑所需的参数

* @return Mono>

*/

Mono> choose(String serviceId, ServerHttpRequest request, ServerWebExchange exchange, LoadBalancerClientFactory clientFactory);

}

3、灰度过滤器

（过滤器主要是重写选择实例的策略）

import com.digital.cnzz.gateway.service.GrayLoadBalancer;

import lombok.extern.slf4j.Slf4j;

import org.apache.http.util.Asserts;

import org.springframework.cloud.client.ServiceInstance;

import org.springframework.cloud.client.loadbalancer.LoadBalancerUriTools;

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.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.support.LoadBalancerClientFactory;

import org.springframework.stereotype.Component;

import org.springframework.web.server.ServerWebExchange;

import reactor.core.publisher.Mono;

import java.net.URI;

/**

* @author xf

* @Title:

* @Description:

* @date 2023/1/12 17:16

*/

@Slf4j

@Component

public class GrayReactiveLoadBalancerClientFilter extends ReactiveLoadBalancerClientFilter {

private final static String SCHEME = "lb";

private static final int LOAD_BALANCER_CLIENT_FILTER_ORDER = 10150;

private final GrayLoadBalancer grayLoadBalancer;

private LoadBalancerProperties loadBalancerProperties;

private final LoadBalancerClientFactory clientFactory;

public GrayReactiveLoadBalancerClientFilter(LoadBalancerClientFactory clientFactory, LoadBalancerProperties loadBalancerProperties, GrayLoadBalancer grayLoadBalancer) {

super(clientFactory, loadBalancerProperties);

this.loadBalancerProperties = loadBalancerProperties;

this.clientFactory = clientFactory;

this.grayLoadBalancer = grayLoadBalancer;

}

@Override

public int getOrder() {

return LOAD_BALANCER_CLIENT_FILTER_ORDER;

}

@Override

public Mono filter(ServerWebExchange exchange, GatewayFilterChain chain) {

URI url = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR);

String schemePrefix = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR);

// 直接放行

if (url == null || (!SCHEME.equals(url.getScheme()) && !SCHEME.equals(schemePrefix))) {

return chain.filter(exchange);

}

// 保留原始url

ServerWebExchangeUtils.addOriginalRequestUrl(exchange, url);

if (log.isTraceEnabled()) {

log.trace(ReactiveLoadBalancerClientFilter.class.getSimpleName() + " url before: " + url);

}

return choose(exchange).doOnNext(response -> {

if (!response.hasServer()) {

throw NotFoundException.create(loadBalancerProperties.isUse404(),

"Unable to find instance for " + url.getHost());

}

URI uri = exchange.getRequest().getURI();

// if the `lb:` mechanism was used, use `` as the default,

// if the loadbalancer doesn't provide one.

String overrideScheme = null;

if (schemePrefix != null) {

overrideScheme = url.getScheme();

}

DelegatingServiceInstance serviceInstance = new DelegatingServiceInstance(response.getServer(),

overrideScheme);

URI requestUrl = LoadBalancerUriTools.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));

}

/**

* 获取实例

* @param exchange ServerWebExchange

* @return ServiceInstance

*/

private Mono> choose(ServerWebExchange exchange) {

URI uri = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR);

Asserts.notNull(uri, "uri");

return grayLoadBalancer.choose(uri.getHost(), exchange.getRequest(),exchange,clientFactory);

}

}

4、基于客户端版本号灰度路由

import cn.hutool.core.collection.CollUtil;

import cn.hutool.core.map.MapUtil;

import cn.hutool.core.util.RandomUtil;

import com.digital.cnzz.gateway.service.GrayLoadBalancer;

import com.github.pagehelper.util.StringUtil;

import lombok.RequiredArgsConstructor;

import lombok.extern.slf4j.Slf4j;

import org.apache.commons.collections4.CollectionUtils;

import org.springframework.cloud.client.ServiceInstance;

import org.springframework.cloud.client.discovery.DiscoveryClient;

import org.springframework.cloud.client.loadbalancer.reactive.DefaultResponse;

import org.springframework.cloud.client.loadbalancer.reactive.ReactiveLoadBalancer;

import org.springframework.cloud.client.loadbalancer.reactive.Request;

import org.springframework.cloud.client.loadbalancer.reactive.Response;

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.http.server.reactive.ServerHttpRequest;

import org.springframework.stereotype.Component;

import org.springframework.web.server.ServerWebExchange;

import reactor.core.publisher.Mono;

import java.net.URI;

import java.util.List;

import java.util.stream.Collectors;

/**

* @author xf

* @Title:

* @Description:

* @date 2023/1/12 17:18

*/

@Slf4j

@RequiredArgsConstructor

@Component

public class VersionGrayLoadBalancer implements GrayLoadBalancer {

private final DiscoveryClient discoveryClient;

/**

* 根据serviceId 筛选可用服务

* @param serviceId 服务ID

* @param request 当前请求

* @param exchange 请求不到目标实例时，走(父级)默认逻辑所需的参数

* @param clientFactory 请求不到目标实例时，走(父级)默认逻辑所需的参数

* @return return Mono>

*/

@Override

public Mono> choose(String serviceId, ServerHttpRequest request, ServerWebExchange exchange, LoadBalancerClientFactory clientFactory) {

List instances = discoveryClient.getInstances(serviceId);

// 注册中心无实例 抛出异常

if (CollectionUtils.isEmpty(instances)) {

log.warn("No instance available for {}", serviceId);

throw new NotFoundException("No instance available for " + serviceId);

}

// 获取请求version，无则调用父类的策略调用可用实例

String reqVersion = request.getHeaders().getFirst("VERSION");

if (StringUtil.isEmpty(reqVersion)) {

//走父级默认负载均衡策略

return chooseSuper(exchange,clientFactory);

}

// 遍历可以实例元数据，若匹配则返回此实例

List availableList = instances.stream()

.filter(instance -> reqVersion

.equalsIgnoreCase(MapUtil.getStr(instance.getMetadata(), "VERSION")))

.collect(Collectors.toList());

if (CollUtil.isEmpty(availableList)) {

//走父级默认负载均衡策略

return chooseSuper(exchange,clientFactory);

}

return Mono.just(new DefaultResponse(availableList.get(RandomUtil.randomInt(availableList.size()))));

}

public Mono> chooseSuper(ServerWebExchange exchange, LoadBalancerClientFactory clientFactory) {

//父级逻辑，具体实现可参考 org.springframework.cloud.gateway.filter.ReactiveLoadBalancerClientFilter.choose 方法

URI uri = (URI)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR);

ReactorLoadBalancer loadBalancer = (ReactorLoadBalancer)clientFactory.getInstance(uri.getHost(), ReactorLoadBalancer.class, new Class[]{ServiceInstance.class});

if (loadBalancer == null) {

throw new NotFoundException("No loadbalancer available for " + uri.getHost());

} else {

return loadBalancer.choose(this.createRequest());

}

}

private Request createRequest() {

return ReactiveLoadBalancer.REQUEST;

}

}

5、改造前端代码，请求头（Request Headers）加版本号信息