前言

之前写过 spring-cloud-gateway 系列文章, 今天再来补充一篇关于灰度发布的。传送门:

今天的文章主题会按照如下三步曲进行记录:

基于 nacos 的基础项目搭建
动态路由
灰度方案

之前的文章吃了有些没有版本号和文档上传不完整的亏, 导致很多网友咨询的时候我也不记得细节, 这里我们会贴出完整配置及代码。

基础环境搭建

很久没有搭建 SpringCloud 项目了, 首先搭建一个基础示例, 供代码调试。

首先, 快速搭建 nacos-server, 这里基于官方文档压缩包安装。安装完成后访问 http://127.0.0.1:8848/nacos 即可看到 nacos 控制面板
项目创建。我们计划创建 2 个服务, 一个服务提供者 provider，一个网关 gateway。项目采用聚合项目的形式。

根目录 pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>cn.idea360</groupId>
    <artifactId>spring-cloud-demo</artifactId>
    <version>0.0.1</version>
    <packaging>pom</packaging>

    <properties>
        <maven.compiler.source>11</maven.compiler.source>
        <maven.compiler.target>11</maven.compiler.target>
        <spring-boot.version>2.3.7.RELEASE</spring-boot.version>
        <spring-cloud-alibaba.version>2.2.2.RELEASE</spring-cloud-alibaba.version>
        <spring-cloud.version>Hoxton.SR9</spring-cloud.version>
    </properties>

    <modules>
        <module>provider</module>
        <module>gateway</module>
    </modules>

    <dependencies>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>${spring-cloud-alibaba.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
</project>

服务提供者 provider

这里我们计划引入 nacos, 所以先创建一个 nacos 配置文件 dataId 为 provider.properties, 这里用默认的命名空间 public, 默认分组 DEFAULT_GROUP

version=2

provider 的 pom 文件如下:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd
http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <artifactId>provider</artifactId>

    <parent>
        <groupId>cn.idea360</groupId>
        <artifactId>spring-cloud-demo</artifactId>
        <version>0.0.1</version>
    </parent>
    <name>provider</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring-boot.version>2.3.7.RELEASE</spring-boot.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.3.7.RELEASE</version>
                <configuration>
                    <mainClass>cn.idea360.provider.ProviderApplication</mainClass>
                </configuration>
                <executions>
                    <execution>
                        <id>repackage</id>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

application.properties 配置:

# 应用名称
spring.application.name=provider
# 应用服务 WEB 访问端口
server.port=9001

spring.cloud.nacos.config.server-addr=127.0.0.1:8848
spring.cloud.nacos.discovery.server-addr=127.0.0.1:8848

在启动类, 我们增加了服务发现注解 @EnableDiscoveryClient

package cn.idea360.provider;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@EnableDiscoveryClient
@SpringBootApplication
public class ProviderApplication {

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

}

controller 逻辑很简单, 只是简单返回版本号

package cn.idea360.provider.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.core.env.Environment;
import org.springframework.web.bind.annotation.*;

/**
 * @author cuishiying
 * @date 2021-01-22
 */
@RefreshScope
@RestController
@RequestMapping("/test")
public class TestController {

    @Autowired
    private Environment env;

    @Value("${version:0}")
    private String version;
    /**
     * http://localhost:9001/test/port
     * @return
     */
    @GetMapping("/port")
    public Object port() {
        return String.format("port=%s, version=%s", env.getProperty("local.server.port"), version);
    }
}

网关 gateway

gateway 服务的 pom 配置如下:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <artifactId>gateway</artifactId>
    <parent>
        <groupId>cn.idea360</groupId>
        <artifactId>spring-cloud-demo</artifactId>
        <version>0.0.1</version>
    </parent>
    <name>gateway</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring-boot.version>2.3.7.RELEASE</spring-boot.version>
        <spring-cloud-alibaba.version>2.2.2.RELEASE</spring-cloud-alibaba.version>
        <spring-cloud.version>Hoxton.SR9</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>2.3.7.RELEASE</version>
                <configuration>
                    <mainClass>cn.idea360.gateway.GatewayApplication</mainClass>
                </configuration>
                <executions>
                    <execution>
                        <id>repackage</id>
                        <goals>
                            <goal>repackage</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

网关同样做服务发现

package cn.idea360.gateway;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@EnableDiscoveryClient
@SpringBootApplication
public class GatewayApplication {

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

}

网关核心配置, 这里我们先采用静态路由的方式测试下项目是否有问题

application.yml

# 应用服务 WEB 访问端口
server:
  port: 9000
# 应用名称
spring:
  application:
    name: gateway
  cloud:
    nacos:
      config:
        server-addr: 127.0.0.1:8848
      discovery:
        server-addr: 127.0.0.1:8848
    gateway:
      routes: # http://127.0.0.1:9000/actuator/gateway/routes
        - id: provider  # 路由 ID，保持唯一
          uri: lb://provider # uri指目标服务地址，lb代表从注册中心获取服务
          predicates:
            - Path=/provider/**  # http://127.0.0.1:9000/provider/port 会转发到 http://localhost:9001/provider/port, 和预期不符合, 需要StripPrefix来处理
          filters:
            - StripPrefix=1 # StripPrefix=1就代表截取路径的个数为1, 这样请求 http://127.0.0.1:9000/provider/test/port 会转发到 http://localhost:9001/test/port

接下来就是激动人心的时刻了, 先测试下服务是否 ok.

➜  blog git:(master) ✗ curl http://localhost:9001/test/port
port=9001, version=2%
➜  blog git:(master) ✗ curl http://127.0.0.1:9000/provider/test/port
port=9001, version=2%

通过结果可见, 网关的基本配置已经生效了。

基于 nacos 动态路由

动态路由的实现有 2 种方式, 一个就是像之前一样改写 RouteDefinitionRepository, 一个就是基于 nacos 的监听器给 RouteDefinitionRepository 动态更新值。实现逻辑大同小异。

基于 nacos 监听器实现动态路由

配置 nacos 配置文件 gateway-router.json, 为了避免项目 application.yml 中配置文件影响, 先注释掉 gateway 相关的配置

[{
    "id": "provider",
    "predicates": [{
        "name": "Path",
        "args": {
            "_genkey_0": "/provider/**"
        }
    }],
    "filters": [{
        "name": "StripPrefix",
        "args": {
            "_genkey_0": "1"
        }
    }],
    "uri": "lb://provider",
    "order": 0
}]

基于 nacos 监听器实现路由刷新

package cn.idea360.gateway.config;

import com.alibaba.nacos.api.NacosFactory;
import com.alibaba.nacos.api.config.ConfigService;
import com.alibaba.nacos.api.config.listener.Listener;
import com.alibaba.nacos.api.exception.NacosException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.gateway.event.RefreshRoutesEvent;
import org.springframework.cloud.gateway.route.RouteDefinition;
import org.springframework.cloud.gateway.route.RouteDefinitionWriter;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;
import org.springframework.stereotype.Component;
import reactor.core.publisher.Mono;

import javax.annotation.PostConstruct;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Executor;

/**
 * @author cuishiying
 * @date 2021-01-22
 */
@Component
public class DynamicGatewayRouteConfig implements ApplicationEventPublisherAware {

    private String dataId = "gateway-router.json";

    private String group = "DEFAULT_GROUP";

    @Value("${spring.cloud.nacos.config.server-addr}")
    private String serverAddr;

    @Autowired
    private RouteDefinitionWriter routeDefinitionWriter;

    private ApplicationEventPublisher applicationEventPublisher;

    private static final List<String> ROUTE_LIST = new ArrayList<String>();

    private ObjectMapper objectMapper = new ObjectMapper();

    @PostConstruct
    public void dynamicRouteByNacosListener() {
        try {
            ConfigService configService = NacosFactory.createConfigService(serverAddr);
            configService.getConfig(dataId, group, 5000);
            configService.addListener(dataId, group, new Listener() {

                public void receiveConfigInfo(String configInfo) {
                    clearRoute();
                    try {
                        List<RouteDefinition> gatewayRouteDefinitions = objectMapper.readValue(configInfo, new TypeReference<List<RouteDefinition>>() {});
                        for (RouteDefinition routeDefinition : gatewayRouteDefinitions) {
                            addRoute(routeDefinition);
                        }
                        publish();
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }

                public Executor getExecutor() {
                    return null;
                }
            });
        } catch (NacosException e) {
            e.printStackTrace();
        }
    }

    private void clearRoute() {
        for (String id : ROUTE_LIST) {
            this.routeDefinitionWriter.delete(Mono.just(id)).subscribe();
        }
        ROUTE_LIST.clear();
    }

    private void addRoute(RouteDefinition definition) {
        try {
            routeDefinitionWriter.save(Mono.just(definition)).subscribe();
            ROUTE_LIST.add(definition.getId());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private void publish() {
        this.applicationEventPublisher.publishEvent(new RefreshRoutesEvent(this.routeDefinitionWriter));
    }

    public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) {
        this.applicationEventPublisher = applicationEventPublisher;
    }
}

重启网关, 请求 http://127.0.0.1:9000/actuator/gateway/routes 可以发现配置已生效。

[
    {
        "predicate": "Paths: [/provider/**], match trailing slash: true",
        "route_id": "provider",
        "filters": [
            "[[StripPrefix parts = 1], order = 1]"
        ],
        "uri": "lb://provider",
        "order": 0
    }
]

路由测试结果如下:

➜  blog git:(master) ✗ curl http://127.0.0.1:9000/provider/test/port
port=9001, version=2%

基于 RouteDefinitionRepository 实现动态路由

Spring Cloud Gateway 中加载路由信息分别由以下几个类负责

1、PropertiesRouteDefinitionLocator：从配置文件中读取路由信息(如 YML、Properties 等) 2、RouteDefinitionRepository：从存储器中读取路由信息(如内存、配置中心、Redis、MySQL 等) 3、DiscoveryClientRouteDefinitionLocator：从注册中心中读取路由信息(如 Nacos、Eurka、Zookeeper 等)

package cn.idea360.gateway.router;

import com.alibaba.cloud.nacos.NacosConfigManager;
import com.alibaba.nacos.api.config.listener.Listener;
import com.alibaba.nacos.api.exception.NacosException;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.collect.Lists;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.gateway.event.RefreshRoutesEvent;
import org.springframework.cloud.gateway.route.RouteDefinition;
import org.springframework.cloud.gateway.route.RouteDefinitionRepository;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;
import org.springframework.stereotype.Component;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

import javax.annotation.PostConstruct;
import java.util.List;
import java.util.concurrent.Executor;


/**
 * @author cuishiying
 * @date 2021-01-22
 */
@Component
public class NacosRouteDefinitionRepository implements RouteDefinitionRepository, ApplicationEventPublisherAware {

    private static final Logger log = LoggerFactory.getLogger(NacosRouteDefinitionRepository.class);

    @Autowired
    private NacosConfigManager nacosConfigManager;

    // 更新路由信息需要的
    private ApplicationEventPublisher applicationEventPublisher;

    private String dataId = "gateway-router.json";

    private String group = "DEFAULT_GROUP";

    @Value("${spring.cloud.nacos.config.server-addr}")
    private String serverAddr;

    private ObjectMapper objectMapper = new ObjectMapper();

    @PostConstruct
    public void dynamicRouteByNacosListener() {
        try {
            nacosConfigManager.getConfigService().addListener(dataId, group, new Listener() {

                public void receiveConfigInfo(String configInfo) {
                    log.info("自动更新配置...\r\n{}", configInfo);
                    applicationEventPublisher.publishEvent(new RefreshRoutesEvent(this));
                }

                public Executor getExecutor() {
                    return null;
                }
            });
        } catch (NacosException e) {
            e.printStackTrace();
        }
    }

    @Override
    public Flux<RouteDefinition> getRouteDefinitions() {
        try {
            String configInfo = nacosConfigManager.getConfigService().getConfig(dataId, group, 5000);
            List<RouteDefinition> gatewayRouteDefinitions = objectMapper.readValue(configInfo, new TypeReference<List<RouteDefinition>>() {
            });
            return Flux.fromIterable(gatewayRouteDefinitions);
        } catch (NacosException e) {
            e.printStackTrace();
        } catch (JsonMappingException e) {
            e.printStackTrace();
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
        return Flux.fromIterable(Lists.newArrayList());
    }

    @Override
    public Mono<Void> save(Mono<RouteDefinition> route) {
        return null;
    }

    @Override
    public Mono<Void> delete(Mono<String> routeId) {
        return null;
    }

    @Override
    public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) {
        this.applicationEventPublisher = applicationEventPublisher;
    }
}

测试结果同上。

基于 SpringCloud Gateway + nacos 灰度路由

首先需要明白灰度的场景, 因为有不同版本的服务需要共存, 所以新的节点升级的时候必然代码及配置会存在差别, 所以我们根据这种差别来判断服务版本是新版本还是线上稳定版本。这里我们用 prod 和 gray 来标识 2 个版本。

实现的整体思路：

编写带版本号的灰度路由(负载均衡策略)
编写自定义 filter
nacos 服务配置需要灰度发布的服务的元数据信息以及权重(在服务 jar 中配置)

注意, 应该先修改 nacos 配置实现动态路由, 然后再升级灰度节点. 本案例只是简单示例灰度原理。

网关配置

首先排除掉默认的 ribbon

        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

引入官方新的负载均衡包

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

自定义负载均衡策略

package cn.idea360.gateway.gray;

import org.apache.commons.lang3.StringUtils;
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.NoopServiceInstanceListSupplier;
import org.springframework.cloud.loadbalancer.core.ReactorServiceInstanceLoadBalancer;
import org.springframework.cloud.loadbalancer.core.ServiceInstanceListSupplier;
import org.springframework.http.HttpHeaders;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

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

/**
 * @author cuishiying
 * @date 2021-01-22
 */
public class VersionGrayLoadBalancer implements ReactorServiceInstanceLoadBalancer {

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


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

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

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

    private Response<ServiceInstance> processInstanceResponse(List<ServiceInstance> instances, HttpHeaders headers) {
        if (instances.isEmpty()) {
            return new EmptyResponse();
        } else {
            String reqVersion = headers.getFirst("version");

            if (StringUtils.isEmpty(reqVersion)) {
                return processRibbonInstanceResponse(instances);
            }

            List<ServiceInstance> serviceInstances = instances.stream()
                    .filter(instance -> reqVersion.equals(instance.getMetadata().get("version")))
                    .collect(Collectors.toList());

            if (serviceInstances.size() > 0) {
                return processRibbonInstanceResponse(serviceInstances);
            } else {
                return processRibbonInstanceResponse(instances);
            }
        }
    }

    /**
     * 负载均衡器
     * 参考 org.springframework.cloud.loadbalancer.core.RoundRobinLoadBalancer#getInstanceResponse
     *
     * @author javadaily
     */
    private Response<ServiceInstance> processRibbonInstanceResponse(List<ServiceInstance> instances) {
        int pos = Math.abs(this.position.incrementAndGet());
        ServiceInstance instance = instances.get(pos % instances.size());
        return new DefaultResponse(instance);
    }
}

自定义过滤器加载负载均衡策略

package cn.idea360.gateway.gray;

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.ServiceInstanceListSupplier;
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;

/**
 * @author cuishiying
 * @date 2021-01-22
 */
public class GrayReactiveLoadBalancerClientFilter implements GlobalFilter, Ordered {

    private static final Log log = LogFactory.getLog(ReactiveLoadBalancerClientFilter.class);
    private static final int LOAD_BALANCER_CLIENT_FILTER_ORDER = 10150;
    private final LoadBalancerClientFactory clientFactory;
    private LoadBalancerProperties properties;

    public GrayReactiveLoadBalancerClientFilter(LoadBalancerClientFactory clientFactory, LoadBalancerProperties 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 = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR);
        String schemePrefix = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR);
        if (url != null && ("grayLb".equals(url.getScheme()) || "grayLb".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 {
                    URI uri = exchange.getRequest().getURI();
                    String overrideScheme = null;
                    if (schemePrefix != null) {
                        overrideScheme = url.getScheme();
                    }

                    DelegatingServiceInstance serviceInstance = new DelegatingServiceInstance((ServiceInstance)response.getServer(), 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);
        }
    }

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

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

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

注入过滤器

package cn.idea360.gateway.gray;

import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.cloud.gateway.config.LoadBalancerProperties;
import org.springframework.cloud.loadbalancer.support.LoadBalancerClientFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * @author cuishiying
 * @date 2021-01-22
 */
@Configuration
public class GrayGatewayReactiveLoadBalancerClientAutoConfiguration {

    @Bean
    @ConditionalOnMissingBean({GrayReactiveLoadBalancerClientFilter.class})
    public GrayReactiveLoadBalancerClientFilter grayReactiveLoadBalancerClientFilter(LoadBalancerClientFactory clientFactory, LoadBalancerProperties properties) {
        return new GrayReactiveLoadBalancerClientFilter(clientFactory, properties);
    }
}

发布灰度服务

# 应用名称
spring.application.name=provider
# 应用服务 WEB 访问端口
server.port=9002

spring.cloud.nacos.config.server-addr=127.0.0.1:8848
spring.cloud.nacos.discovery.server-addr=127.0.0.1:8848
spring.cloud.nacos.discovery.metadata.version = gray

测试, curl -X GET -H "version:gray" -d '{"name": "admin"}' http://127.0.0.1:9000/provider/test/port 发现会永远路由到 9002

最后

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Spring Cloud Gateway+nacos灰度发布

前言