前言

　　Nacos最近項目一直在使用，其簡單靈活，支持更細粒度的命令空間，分組等爲麻煩複雜的環境切換提供了方便；同時也很好支持動態路由的配置，只需要簡單的幾步即可。在國產的註冊中心、配置中心中比較突出，容易上手，本文通過gateway、nacos-consumer、nacos-provider三個簡單模塊來展示：Nacos下動態路由配置。

一、Nacos環境準備

1、啓動Nacos配置中心並創建路由配置

具體的Nacos怎麼配置就不介紹了，可以參考阿里巴巴的官方介紹，這裏通過windows直接本地啓動開啓單機模式，登錄Nacos Console，創建dev的namespace，在dev下的默認分組下創建gateway-router的dataId

gateway-router的主要初始化配置如下：關於gateway的組成（id，order、predicates斷言，uri）這裏就不詳細說明的了，可以自行百度下

[{
    "id": "consumer-router",
    "order": 0,
    "predicates": [{
        "args": {
            "pattern": "/consume/**"
        },
        "name": "Path"
    }],
    "uri": "lb://nacos-consumer"
},{
    "id": "provider-router",
    "order": 2,
    "predicates": [{
        "args": {
            "pattern": "/provide/**"
        },
        "name": "Path"
    }],
    "uri": "lb://nacos-provider"
}]

2、連接Nacos配置中心

通常在項目中配置“配置中心”往往都是在bootstrap.propertis(yaml)中配置，這樣才能保證項目中路由配置從Nacos Config中讀取。

# nacos配置中心配置建議在bootstrap.properties中配置
spring.cloud.nacos.config.server-addr=127.0.0.1:8848
#spring.cloud.nacos.config.file-extension=properties
# 配置中心的命名空間：dev 的命名空間（環境）
spring.cloud.nacos.config.namespace=08ecd1e5-c042-410a-84d5-b0a8fbeed8ea

Application啓動類中增加註解@EnableDiscoveryClient，才能保證連接到Nacos Config

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

二、項目構建

1、項目結構

創建簡單的spring boot多模塊結構，推薦使用idea創建

1）Nacos父模塊：

<groupId>com.springcloud</groupId>
<artifactId>nacos</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>nacos</name>
<description>Nacos Demo</description>

首先pom文件引入Spring Cloud Alibaba Nacos組件：註冊中心nacos-discovery與配置中心nacos-config

 <!--nacos 客戶端 註冊中心-->
 <dependency>
　　<groupId>com.alibaba.cloud</groupId>
　　<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
　　<version>${alibaba-nacos.version}</version>
 </dependency>
  <!--nacos 客戶端 配置中心-->
 <dependency>
　　<groupId>com.alibaba.cloud</groupId>
　　<artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
　　<version>${alibaba-nacos.version}</version>
 </dependency>

其次再引入Spring Cloud相關組件依賴

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

其它組件依賴引入（修正：如果引入了nacos-api相關的JSON依賴，那麼fastjson就不需要再引入了，否則可能衝突）：

<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>${fastjson.version}</version>
</dependency>
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>${lombok.version}</version>
    <scope>provided</scope>
</dependency>
<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-api</artifactId>
    <version>${slf4j.version}</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

注意，這裏有個坑，spring cloud gateway使用的web框架爲webflux，和springMVC不兼容。所以不要引入（修正：只有gateway服務不用引入springMVC，其他需要引入）

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

2）三個子模塊：gateway、nacos-consumer、nacos-provider

<modules>
　　<module>nacos-provider</module>
　　<module>nacos-consumer</module>
　　<module>gateway</module>
</modules>

結構截圖如下所示：

3）三個服務的端口分別爲：

　　nacos-consume:6001

　　nacos-provider:6002

　　gateway：6003

4）服務架構如下：

2、編寫測試代碼

（1）在gateway模塊中主要實現以下功能：

第一，從Nacos配置中心中加載動態路由的相關配置，就需要讀取Nacos的命名空間namespace，通過dataId獲取配置

/**
 * 路由類配置
 */
@Configuration
public class GatewayConfig {
    public static final long DEFAULT_TIMEOUT = 30000;

    public static String NACOS_SERVER_ADDR;

    public static String NACOS_NAMESPACE;

    public static String NACOS_ROUTE_DATA_ID;

    public static String NACOS_ROUTE_GROUP;

    @Value("${spring.cloud.nacos.discovery.server-addr}")
    public void setNacosServerAddr(String nacosServerAddr){
        NACOS_SERVER_ADDR = nacosServerAddr;
    }

    @Value("${spring.cloud.nacos.discovery.namespace}")
    public void setNacosNamespace(String nacosNamespace){
        NACOS_NAMESPACE = nacosNamespace;
    }

    @Value("${nacos.gateway.route.config.data-id}")
    public void setNacosRouteDataId(String nacosRouteDataId){
        NACOS_ROUTE_DATA_ID = nacosRouteDataId;
    }

    @Value("${nacos.gateway.route.config.group}")
    public void setNacosRouteGroup(String nacosRouteGroup){
        NACOS_ROUTE_GROUP = nacosRouteGroup;
    }

}

properties配置關於Nacos下讀取gateway-router的配置：

spring.cloud.nacos.discovery.server-addr=127.0.0.1:8848
spring.cloud.nacos.discovery.namespace=08ecd1e5-c042-410a-84d5-b0a8fbeed8ea
nacos.gateway.route.config.data-id=gateway-router
nacos.gateway.route.config.group=DEFAULT_GROUP

第二，初始化路由，監聽動態路由配置的數據源變化；

/**
 *
 * 通過nacos下發動態路由配置,監聽Nacos中gateway-route配置
 *
 */
@Component
@Slf4j
@DependsOn({"gatewayConfig"}) // 依賴於gatewayConfig bean
public class DynamicRouteServiceImplByNacos {

    @Autowired
    private DynamicRouteServiceImpl dynamicRouteService;


    private ConfigService configService;

    @PostConstruct
    public void init() {
        log.info("gateway route init...");
        try{
            configService = initConfigService();
            if(configService == null){
                log.warn("initConfigService fail");
                return;
            }
            String configInfo = configService.getConfig(GatewayConfig.NACOS_ROUTE_DATA_ID, GatewayConfig.NACOS_ROUTE_GROUP, GatewayConfig.DEFAULT_TIMEOUT);
            log.info("獲取網關當前配置:\r\n{}",configInfo);
            List<RouteDefinition> definitionList = JSON.parseArray(configInfo, RouteDefinition.class);
            for(RouteDefinition definition : definitionList){
                log.info("update route : {}",definition.toString());
                dynamicRouteService.add(definition);
            }
        } catch (Exception e) {
            log.error("初始化網關路由時發生錯誤",e);
        }
        dynamicRouteByNacosListener(GatewayConfig.NACOS_ROUTE_DATA_ID,GatewayConfig.NACOS_ROUTE_GROUP);
    }

    /**
     * 監聽Nacos下發的動態路由配置
     * @param dataId
     * @param group
     */
    public void dynamicRouteByNacosListener (String dataId, String group){
        try {
            configService.addListener(dataId, group, new Listener()  {
                @Override
                public void receiveConfigInfo(String configInfo) {
                    log.info("進行網關更新:\n\r{}",configInfo);
                    List<RouteDefinition> definitionList = JSON.parseArray(configInfo, RouteDefinition.class);
                    for(RouteDefinition definition : definitionList){
                        log.info("update route : {}",definition.toString());
                        dynamicRouteService.update(definition);
                    }
                }
                @Override
                public Executor getExecutor() {
                    log.info("getExecutor\n\r");
                    return null;
                }
            });
        } catch (NacosException e) {
            log.error("從nacos接收動態路由配置出錯!!!",e);
        }
    }

    /**
     * 初始化網關路由 nacos config
     * @return
     */
    private ConfigService initConfigService(){
        try{
            Properties properties = new Properties();
            properties.setProperty("serverAddr",GatewayConfig.NACOS_SERVER_ADDR);
            properties.setProperty("namespace",GatewayConfig.NACOS_NAMESPACE);
            return configService= NacosFactory.createConfigService(properties);
        } catch (Exception e) {
            log.error("初始化網關路由時發生錯誤",e);
            return null;
        }
    }
}

第三，刷新最新的動態路由變化，實現動態增刪改路由

/**
 * 動態更新路由網關service
 * 1）實現一個Spring提供的事件推送接口ApplicationEventPublisherAware
 * 2）提供動態路由的基礎方法，可通過獲取bean操作該類的方法。該類提供新增路由、更新路由、刪除路由，然後實現發佈的功能。
 */
@Slf4j
@Service
public class DynamicRouteServiceImpl implements ApplicationEventPublisherAware {
    @Autowired
    private RouteDefinitionWriter routeDefinitionWriter;

    /**
     * 發佈事件
     */
    @Autowired
    private ApplicationEventPublisher publisher;

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

    /**
     * 刪除路由
     * @param id
     * @return
     */
    public String delete(String id) {
        try {
            log.info("gateway delete route id {}",id);
            this.routeDefinitionWriter.delete(Mono.just(id));
            return "delete success";
        } catch (Exception e) {
            return "delete fail";
        }
    }
    /**
     * 更新路由
     * @param definition
     * @return
     */
    public String update(RouteDefinition definition) {
        try {
            log.info("gateway update route {}",definition);
            this.routeDefinitionWriter.delete(Mono.just(definition.getId()));
        } catch (Exception e) {
            return "update fail,not find route  routeId: "+definition.getId();
        }
        try {
            routeDefinitionWriter.save(Mono.just(definition)).subscribe();
            this.publisher.publishEvent(new RefreshRoutesEvent(this));
            return "success";
        } catch (Exception e) {
            return "update route fail";
        }
    }

    /**
     * 增加路由
     * @param definition
     * @return
     */
    public String add(RouteDefinition definition) {
        log.info("gateway add route {}",definition);
        routeDefinitionWriter.save(Mono.just(definition)).subscribe();
        this.publisher.publishEvent(new RefreshRoutesEvent(this));
        return "success";
    }
}

（2）在consumer創建ConsumeController：通過訪問gateway網關/consume/sayHello/{name}（"pattern": "/consume/**"）,跳轉至nacos-consumer服務（"uri": "lb://nacos-consumer"），

@RequestMapping("/consume/")
@Slf4j
public class ConsumeController {

    @GetMapping("/sayHello/{name}")
    public String sayHello(@PathVariable("name") String name){
        log.info("I'm calling nacos-consumer service by dynamic gateway...");
        return name + " Hi~, I'm from nacos-consumer";
    }
}

（3）在provider創建ProviderController：通過訪問gateway網關/provide/sayHello/{name}（"pattern": "/provide/**"）,跳轉至nacos-provider服務（"uri": "lb://nacos-provider"）

@RestController
@RequestMapping("/provide/")
@Slf4j
public class ProviderController {

    @GetMapping("/sayHello/{name}")
    public String sayHello(@PathVariable("name") String name){
        log.info("I'm calling nacos-provider service by dynamic gateway...");
        return name + " Hi~, I'm from nacos-provider";
    }
}

三、測試動態網關配置

1、啓動服務，觀察註冊中心

分別啓動gateway、nacos-consumer、nacos-provider三個服務，觀察是否已經在Nacos上正確註冊

注意：需要指定註冊中心的namespace爲dev的空間，即spring.cloud.nacos.discovery.namespace=08ecd1e5-c042-410a-84d5-b0a8fbeed8ea

2、訪問網關，觀察服務日誌

（1）查看gateway服務的初始化啓動日誌：會發現可以正常從Nacos獲取配置gateway-router網關配置文件內容，並進行正確路由加載...

2020-05-10 14:33:44.557  INFO 1272 --- [           main] c.g.r.DynamicRouteServiceImplByNacos     : gateway route init...
2020-05-10 14:33:44.578  INFO 1272 --- [           main] c.g.r.DynamicRouteServiceImplByNacos     : 獲取網關當前配置:
[{
    "id": "consumer-router",
    "order": 0,
    "predicates": [{
        "args": {
            "pattern": "/consume/**"
        },
        "name": "Path"
    }],
    "uri": "lb://nacos-consumer"
},{
    "id": "provider-router",
    "order": 2,
    "predicates": [{
        "args": {
            "pattern": "/provide/**"
        },
        "name": "Path"
    }],
    "uri": "lb://nacos-provider"
}]
2020-05-10 14:33:44.691  INFO 1272 --- [           main] c.g.r.DynamicRouteServiceImplByNacos     : update route : RouteDefinition{id='consumer-router', predicates=[PredicateDefinition{name='Path', args={pattern=/consume/**}}], filters=[], uri=lb://nacos-consumer, order=0, metadata={}}
2020-05-10 14:33:44.691  INFO 1272 --- [           main] c.g.service.DynamicRouteServiceImpl      : gateway add route RouteDefinition{id='consumer-router', predicates=[PredicateDefinition{name='Path', args={pattern=/consume/**}}], filters=[], uri=lb://nacos-consumer, order=0, metadata={}}
2020-05-10 14:33:45.192  INFO 1272 --- [           main] o.s.c.g.r.RouteDefinitionRouteLocator    : Loaded RoutePredicateFactory [After]
2020-05-10 14:33:45.192  INFO 1272 --- [           main] o.s.c.g.r.RouteDefinitionRouteLocator    : Loaded RoutePredicateFactory [Before]
2020-05-10 14:33:45.192  INFO 1272 --- [           main] o.s.c.g.r.RouteDefinitionRouteLocator    : Loaded RoutePredicateFactory [Between]
2020-05-10 14:33:45.193  INFO 1272 --- [           main] o.s.c.g.r.RouteDefinitionRouteLocator    : Loaded RoutePredicateFactory [Cookie]
2020-05-10 14:33:45.193  INFO 1272 --- [           main] o.s.c.g.r.RouteDefinitionRouteLocator    : Loaded RoutePredicateFactory [Header]
2020-05-10 14:33:45.193  INFO 1272 --- [           main] o.s.c.g.r.RouteDefinitionRouteLocator    : Loaded RoutePredicateFactory [Host]
2020-05-10 14:33:45.194  INFO 1272 --- [           main] o.s.c.g.r.RouteDefinitionRouteLocator    : Loaded RoutePredicateFactory [Method]
2020-05-10 14:33:45.194  INFO 1272 --- [           main] o.s.c.g.r.RouteDefinitionRouteLocator    : Loaded RoutePredicateFactory [Path]
2020-05-10 14:33:45.194  INFO 1272 --- [           main] o.s.c.g.r.RouteDefinitionRouteLocator    : Loaded RoutePredicateFactory [Query]
2020-05-10 14:33:45.194  INFO 1272 --- [           main] o.s.c.g.r.RouteDefinitionRouteLocator    : Loaded RoutePredicateFactory [ReadBodyPredicateFactory]
2020-05-10 14:33:45.194  INFO 1272 --- [           main] o.s.c.g.r.RouteDefinitionRouteLocator    : Loaded RoutePredicateFactory [RemoteAddr]
2020-05-10 14:33:45.194  INFO 1272 --- [           main] o.s.c.g.r.RouteDefinitionRouteLocator    : Loaded RoutePredicateFactory [Weight]
2020-05-10 14:33:45.194  INFO 1272 --- [           main] o.s.c.g.r.RouteDefinitionRouteLocator    : Loaded RoutePredicateFactory [CloudFoundryRouteService]
2020-05-10 14:33:45.335  INFO 1272 --- [           main] c.g.r.DynamicRouteServiceImplByNacos     : update route : RouteDefinition{id='provider-router', predicates=[PredicateDefinition{name='Path', args={pattern=/provide/**}}], filters=[], uri=lb://nacos-provider, order=2, metadata={}}
2020-05-10 14:33:45.335  INFO 1272 --- [           main] c.g.service.DynamicRouteServiceImpl      : gateway add route RouteDefinition{id='provider-router', predicates=[PredicateDefinition{name='Path', args={pattern=/provide/**}}], filters=[], uri=lb://nacos-provider, order=2, metadata={}}
2020-05-10 14:33:45.336  INFO 1272 --- [           main] c.g.r.DynamicRouteServiceImplByNacos     : update route : RouteDefinition{id='github-router', predicates=[PredicateDefinition{name='Path', args={pattern=/github}}], filters=[], uri=https://github.com, order=3, metadata={}}
2020-05-10 14:33:45.336  INFO 1272 --- [           main] c.g.service.DynamicRouteServiceImpl      : gateway add route RouteDefinition{id='github-router', predicates=[PredicateDefinition{name='Path', args={pattern=/github}}], filters=[], uri=https://github.com, order=3, metadata={}}

View Code

但這隻能說明是初始化靜態路由，下面我們改變gateway-router網關配置內容，追加github-router路由

[{
    "id": "consumer-router",
    "order": 0,
    "predicates": [{
        "args": {
            "pattern": "/consume/**"
        },
        "name": "Path"
    }],
    "uri": "lb://nacos-consumer"
},{
    "id": "provider-router",
    "order": 2,
    "predicates": [{
        "args": {
            "pattern": "/provide/**"
        },
        "name": "Path"
    }],
    "uri": "lb://nacos-provider"
},{
    "id": "github-router",
    "order": 2,
    "predicates": [{
        "args": {
            "pattern": "/github/**"
        },
        "name": "Path"
    }],
    "uri": "https://github.com"
}]

之後點擊發布更新路由配置

觀察gateway服務日誌，有沒有監聽，並且進行正確的路由更新：如下日誌所示，最新路由配置立馬被打印，並且進行正確路由更新

2020-05-10 14:42:27.576  INFO 1272 --- [d5-b0a8fbeed8ea] c.g.r.DynamicRouteServiceImplByNacos     : 進行網關更新:

[{
    "id": "consumer-router",
    "order": 0,
    "predicates": [{
        "args": {
            "pattern": "/consume/**"
        },
        "name": "Path"
    }],
    "uri": "lb://nacos-consumer"
},{
    "id": "provider-router",
    "order": 2,
    "predicates": [{
        "args": {
            "pattern": "/provide/**"
        },
        "name": "Path"
    }],
    "uri": "lb://nacos-provider"
},{
    "id": "github-router",
    "order": 2,
    "predicates": [{
        "args": {
            "pattern": "/github/**"
        },
        "name": "Path"
    }],
    "uri": "https://github.com"
}]
2020-05-10 14:42:27.576  INFO 1272 --- [d5-b0a8fbeed8ea] c.g.r.DynamicRouteServiceImplByNacos     : update route : RouteDefinition{id='consumer-router', predicates=[PredicateDefinition{name='Path', args={pattern=/consume/**}}], filters=[], uri=lb://nacos-consumer, order=0, metadata={}}
2020-05-10 14:42:27.576  INFO 1272 --- [d5-b0a8fbeed8ea] c.g.service.DynamicRouteServiceImpl      : gateway update route RouteDefinition{id='consumer-router', predicates=[PredicateDefinition{name='Path', args={pattern=/consume/**}}], filters=[], uri=lb://nacos-consumer, order=0, metadata={}}
2020-05-10 14:42:27.578  INFO 1272 --- [d5-b0a8fbeed8ea] c.g.r.DynamicRouteServiceImplByNacos     : update route : RouteDefinition{id='provider-router', predicates=[PredicateDefinition{name='Path', args={pattern=/provide/**}}], filters=[], uri=lb://nacos-provider, order=2, metadata={}}
2020-05-10 14:42:27.578  INFO 1272 --- [d5-b0a8fbeed8ea] c.g.service.DynamicRouteServiceImpl      : gateway update route RouteDefinition{id='provider-router', predicates=[PredicateDefinition{name='Path', args={pattern=/provide/**}}], filters=[], uri=lb://nacos-provider, order=2, metadata={}}
2020-05-10 14:42:27.580  INFO 1272 --- [d5-b0a8fbeed8ea] c.g.r.DynamicRouteServiceImplByNacos     : update route : RouteDefinition{id='github-router', predicates=[PredicateDefinition{name='Path', args={pattern=/github/**}}], filters=[], uri=https://github.com, order=2, metadata={}}
2020-05-10 14:42:27.580  INFO 1272 --- [d5-b0a8fbeed8ea] c.g.service.DynamicRouteServiceImpl      : gateway update route RouteDefinition{id='github-router', predicates=[PredicateDefinition{name='Path', args={pattern=/github/**}}], filters=[], uri=https://github.com, order=2, metadata={}}

View Code

其實，還有辦法可以知道我們的gateway服務有沒有監聽Nacos的gateway-router配置，那就是在Nacos Console--->監聽查詢----->選擇配置---->輸入配置文件的namespace與Group：可以發現我本地IP地址127.0.0.1對配置文件gateway-router進行了監聽

（2）訪問gateway網關服務：http://localhost:6003/consume/sayHello/nacos

查看consumer服務日誌：

2020-05-10 14:55:07.257  INFO 6552 --- [nio-6001-exec-2] c.n.c.controller.ConsumeController       : I'm calling nacos-consumer service by dynamic gateway...

發現跳轉至consumer服務，並且訪問了consumer服務的CosnumerController

（3）訪問gateway網關服務：http://localhost:6003/provider/sayHello/nacos

查看provider服務日誌：

2020-05-10 14:56:56.144  INFO 10024 --- [nio-6002-exec-1] c.n.p.controller.ProviderController      : I'm calling nacos-provider service by dynamic gateway...

發現跳轉至consumer服務，並且訪問了provider服務的ProviderController

（4）訪問訪問gateway網關服務：http://localhost:6003/github，正確跳轉至github頁面

四、總結

　　1）Spring Cloud Gateway作用不光只是簡單的跳轉重定向，還可以實現用戶的驗證登錄，解決跨域，日誌攔截，權限控制，限流，熔斷，負載均衡，黑名單和白名單機制等。是微服務架構不二的選擇；

　　2）Nacos的配置中心支持動態獲取配置文件，可以將一些全局的經常變更的配置文件放在Nacos下，需要到微服務自行獲取。

Nacos+Spring Cloud Gateway動態路由配置

前言

一、Nacos環境準備

1、啓動Nacos配置中心並創建路由配置

2、連接Nacos配置中心

二、項目構建

1、項目結構

2、編寫測試代碼

（1）在gateway模塊中主要實現以下功能：

（2）在consumer創建ConsumeController：通過訪問gateway網關/consume/sayHello/{name}（"pattern": "/consume/**"）,跳轉至nacos-consumer服務（"uri": "lb://nacos-consumer"），

（3）在provider創建ProviderController：通過訪問gateway網關/provide/sayHello/{name}（"pattern": "/provide/**"）,跳轉至nacos-provider服務（"uri": "lb://nacos-provider"）

三、測試動態網關配置

1、啓動服務，觀察註冊中心

2、訪問網關，觀察服務日誌

四、總結

Spring Cloud 部署時如何使用 Kubernetes 作爲註冊中心和配置中心

Spring Boot自動配置原理與實踐（二）

MySQL是怎麼解決幻讀問題的？

深入學習Netty（5）——Netty是如何解決TCP粘包/拆包問題的？

深入學習Netty（4）——Netty編程入門

深入學習Netty（2）——傳統NIO編程

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