spring-gateway基于數據庫 + nacos 的動態路由

動態路由的實現方式多種多樣，研究一下基于數據方式的動態路由。

1. 創建項目，并pom.xml文件引入如下依賴

<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>
 <groupId>com.olive</groupId>
 <artifactId>olive-gateway</artifactId>
 <version>0.0.1-SNAPSHOT</version>
 <parent>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-parent</artifactId>
  <version>2.7.1</version>
 </parent>
 <dependencyManagement>
  <dependencies>
   <dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-dependencies</artifactId>
    <version>2021.0.3</version>
    <type>pom</type>
    <scope>import</scope>
   </dependency>
   <dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-alibaba-dependencies</artifactId>
    <version>2021.1</version>
    <type>pom</type>
    <scope>import</scope>
   </dependency>
  </dependencies>
 </dependencyManagement>
 <dependencies>
  <dependency>
   <groupId>org.springframework.cloud</groupId>
   <artifactId>spring-cloud-starter-gateway</artifactId>
  </dependency>
  <dependency>
   <groupId>com.alibaba.cloud</groupId>
   <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
  </dependency>
 </dependencies>
</project>

使用 spring-boot-starter-paren t就不需要給子集pom配置版本號了，因為它包括了

• 定義了 java 編譯版本為 1.8
• 使用 utf-8 格式編碼
• 繼承 spring-boot-dependencies 進行統一版本依賴管理
• 執行打包 war jar 操作配置；可以省略打包 plugin 的配置
• 自動化資源過濾。如 application.properties 和 application.yml 的資源過濾、 包括 profile 多環境配置的
• 自動化插件配置
• 不需要配置 maven 打包 plugin 插件配置

2. 從數據庫加載路由配置

先定義一個接口，該接口的功能主要是返回數據庫配置的所有路由

import org.springframework.cloud.gateway.route.RouteDefinition;
import reactor.core.publisher.Flux;
/**
 * 返回所有路由數據
 */
public interface GatewayRouterService {
    Flux<RouteDefinition> getGatewayRoutes();
}

實現該接口

import java.util.ArrayList;
import java.util.List;
import org.springframework.cloud.gateway.route.RouteDefinition;
import org.springframework.stereotype.Service;
import com.olive.router.GatewayRouterService;
import reactor.core.publisher.Flux;
@Service
public class RouterServiceImpl implements GatewayRouterService {
 @Override
 public Flux<RouteDefinition> getGatewayRoutes() {
     System.out.println("------getGatewayRoutes-------");
     List<RouteDefinition> routes = null;
     //TODO查詢數據庫返回所有有效路由
     return Flux.fromIterable(routes );
 }
}

3. 動態加載路由

實現 RouteDefinitionRepository 接口，Spring自動從數據庫中讀取路由配置；采用 nacos 作為服務發現與配置中心，nacos 自動觸發心跳檢測，網關基于心跳檢測會自動刷新數據庫路由配置，默認 30s 進行一次路由刷新。參考實現 RouteRefreshListener。

import org.springframework.cloud.gateway.route.RouteDefinition;
import org.springframework.cloud.gateway.route.RouteDefinitionRepository;
import com.olive.router.GatewayRouterService;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
public class DatabaseRouteDefinitionRepository implements RouteDefinitionRepository {
    private final GatewayRouterService gatewayRouterService;
    public InDBRouteDefinitionRepository(GatewayRouterService gatewayRouterService) {
        this.gatewayRouterService= gatewayRouterService;
    }
    @Override
    public Flux<RouteDefinition> getRouteDefinitions() {
        return gatewayRouterService.getGatewayRoutes();
    }
    @Override
    public Mono<Void> save(Mono<RouteDefinition> route) {
        //TODO
        return Mono.empty();
    }
    @Override
    public Mono<Void> delete(Mono<String> routeId) {
        //TODO
        return Mono.empty();
    }
}

4. 配置加載自定義的路由

spring-gateway 默認是先從 application.yml 文件加載路由配置；這里通過 AutoConfigureBefore 注解，加載數據庫的路由配置。

import org.springframework.boot.autoconfigure.AutoConfigureBefore;
import org.springframework.boot.autoconfigure.AutoConfigureOrder;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.cloud.gateway.config.GatewayAutoConfiguration;
import org.springframework.cloud.gateway.route.RouteDefinitionRepository;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import com.olive.route.DatabaseRouteDefinitionRepository;
import com.olive.router.GatewayRouterService;
@AutoConfigureBefore(GatewayAutoConfiguration.class)
@AutoConfigureOrder(Ordered.HIGHEST_PRECEDENCE + 5)
@Configuration
public class GatewayConfig {
    /**
     * 網關路由配置實現bean
     */
    @Bean
    @ConditionalOnMissingBean(RouteDefinitionRepository.class)
    @ConditionalOnBean(GatewayRouterService.class)
    public DatabaseRouteDefinitionRepository databaseRouteDefinitionRepository(GatewayRouterService gatewayRouterService) {
        return new DatabaseRouteDefinitionRepository(gatewayRouterService);
    }
    
}

5. 添加 application.yml 配置文件

需要啟動nacos，然后要配置 nacos 注冊中心地址。

server:
  port: 8089
spring:
  application:
    name: olive-gateway
  cloud:
    nacos:
      discovery:
        server-addr: 192.168.255.10:8848

6. 編寫 springboot 啟動引導類

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
@EnableDiscoveryClient
@SpringBootApplication
public class GwApplication {
 public static void main(String[] args) {
   SpringApplication.run(GwApplication.class, args);
 }
 
}