SpringCloud-gateway Redis动态路由及各EndPoint介绍

亦凉 2021-09-03 08:47 355阅读 0赞

# Spring Cloud Gateway 微服务网关 #

*  创建项目（命名 为 Gateway）， 添加pom 依赖
    
        <dependency>
          <groupId>org.springframework.cloud</groupId>
          <artifactId>spring-cloud-starter-gateway</artifactId>
          <version>2.2.0.RELEASE</version>
        </dependency>
        
        <dependency>
          <groupId>com.alibaba.cloud</groupId>
          <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
          <version>2.2.0.RELEASE</version>
        </dependency>
 *  Router 路由器：包括，11种路由模式，具体参见[官网][Link 1]
    
     *  添加路由配置： 意思是所有路径匹配到 /acc/\*\* ，都会路由到 lb://account-service
        
            spring:
              cloud:
                gateway:
                  routes:
                  - id: host_route
                    uri: lb://account-service
                    predicates:
                    - Path=/acc/**
     *  在启动类添加注解，服务注册和发现
        
            @EnableDiscoveryClient
            public class GatewayApplication {
            }
     *  测试
        
         *  默认路由地址：http://localhost:9001/account-service/acc/user?id=2
         *  使用Path路由配置：http://localhost:9001/acc/user?id=2
     *  打开[gateway 监控端点][gateway] ，各端点介绍，参见[Gateway管理API][Gateway_API]
        
            
            <dependency>
              <groupId>org.springframework.boot</groupId>
              <artifactId>spring-boot-starter-actuator</artifactId>
            </dependency>
        
            #将 gateway 端点暴露
            management.endpoint.gateway.enabled=true 
            management.endpoints.web.exposure.include=gateway
        
            查询全局过滤器， http://localhost:9001/actuator/gateway/globalfilters
            查询路由中的过滤器， http://localhost:9001/actuator/gateway/routefilters
            刷新路由缓存， http://localhost:9001/actuator/gateway/refresh
            
            展示路由列表,  http://localhost:9001/actuator/gateway/routes
            获取单个路由的信息， http://localhost:9001/actuator/gateway/routes/host_route
            创建路由，发送Post请求，  ../actuator/gateway/routes/{id_route_to_create}
            删除路由，发送Delete请求： ../actuator/gateway/routes/{id_route_to_delete}
 *  Filter [过滤器][Link 2]
    
     *  网关经常需要对路由请求进行过滤，如鉴权之后构造头部之类的，过滤的种类很多，如增加请求头、增加请求参数 、增加响应头和断路器等等功能，这就用到了Spring Cloud Gateway 的 Filter。
     *  Filter 的作用：
        
         *  当我们有很多个服务时，客户端请求各个服务的Api时，每个服务都需要做相同的事情，比如鉴权、限流、日志输出等。
         *  因此可以将这些功能等转移到网关处理以减少重复开发。
     *  [Filter 的生命周期][Filter]
        
         *  PRE： 这种过滤器在被代理的微服务（Proxied Service）执行之前调用。我们可利用这种过滤器实现身份验证、在集群中选择请求的微服务、记录调试信息等。
         *  POST：这种过滤器在被代理的微服务（Proxied Service）执行完成后执行。这种过滤器可用来为响应添加标准的 HTTP Header、收集统计信息和指标、将响应从微服务发送给客户端等。
     *  Filter 的分类
     *  [GatewayFilter][]：应用到单个路由或者一个分组的路由上。自定义的GatewayFilter，同样需要指定某个路由器
     *  [GlobalFilter][]：应用到所有的路由上。当请求到来时，`Filtering Web Handler` 处理器会添加所有 `GlobalFilter` 实例和匹配的 `GatewayFilter` 实例到过滤器链中。因此，自定义的GlobalFilter，不需要什么额外的配置。
     *  自定义 GatewayFilter，[有两种实现方式][Link 2]
        
         *  一种是直接 实现GatewayFilter接口，不过还需要手动将自定义的GatewayFilter 注册到 router中
            
                // 统计某个或者某种路由的处理时长
                public class CustomerGatewayFilter implements GatewayFilter, Ordered {
                    private static final Logger log = LoggerFactory.getLogger( CustomerGatewayFilter.class );
                    private static final String COUNT_START_TIME = "countStartTime";
                
                    @Override
                    public Mono<Void> filter(ServerWebExchange exch, GatewayFilterChain chain) {
                        return chain.filter(exch).then(
                            Mono.fromRunnable(() -> {
                              long startTime = exch.getAttribute(COUNT_START_TIME);
                              long endTime=(Instant.now().toEpochMilli() - startTime);
                              log.info(exch.getRequest().getURI().getRawPath() + ": " + endTime + "ms");
                          })
                        );
                    }
                
                    @Override
                    public int getOrder() {
                        return 0;
                  }
                }
         *  另一种是 自定义过滤器工厂（继承AbstractGatewayFilterFactory类） , 选择自定义过滤器工厂的方式，可以在配置文件中配置过滤器
            
                @Component
                public class CustomerGatewayFilterFactory extends AbstractGatewayFilterFactory<CustomerGatewayFilterFactory.Config> {
                
                    private static final Logger log = LoggerFactory.getLogger( CustomerGatewayFilterFactory.class );
                    private static final String COUNT_START_TIME = "countStartTime";
                
                    @Override
                    public List<String> shortcutFieldOrder() {
                        return Arrays.asList("enabled");
                    }
                
                    public CustomerGatewayFilterFactory() {
                        super(Config.class);
                        log.info("Loaded GatewayFilterFactory [CustomerGatewayFilterFactory]");
                    }
                
                    @Override
                    public GatewayFilter apply(Config config) {
                        return (exchange, chain) -> {
                            if (!config.isEnabled()) {
                              return chain.filter(exchange);
                            }
                            exchange.getAttributes().put(COUNT_START_TIME, 
                                                         System.currentTimeMillis());
                          
                          return chain.filter(exchange).then(
                                Mono.fromRunnable(() -> {
                                    Long startTime = exchange.getAttribute(COUNT_START_TIME);
                                    if (startTime != null) {
                                        StringBuilder sb = new StringBuilder(
                                          exchange.getRequest().getURI().getRawPath()
                                        ).append(": ")
                                         .append(System.currentTimeMillis() - startTime)
                                         .append("ms");
                
                                        sb.append(" params:")
                                          .append(exchange.getRequest().getQueryParams());
                
                                        log.info(sb.toString());
                                    }}));
                        };
                    }
                
                    public static class Config {
                        //控制是否开启统计
                        private boolean enabled;
                        public Config() {}
                        // getter setter 省略
                    }
                }
            
                spring:
                  cloud:
                    gateway:
                      routes:
                        - id: elapse_route
                          uri: lb://account-service
                          filters:
                          - Customer=true
                          predicates:
                          - Method=GET
     *  自定义GlobalFilter ： 可以在这里实现授权、日志等功能
        
            @Component
            public class AuthorizeFilter implements GlobalFilter, Ordered {
                private static final Logger log = LoggerFactory.getLogger(AuthorizeFilter.class);
                private static final String AUTHORIZE_TOKEN = "token";
            
                @Override
                public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain){
                    String token = exchange.getRequest().getQueryParams()
                      .getFirst(AUTHORIZE_TOKEN);
            
                    if ( StringUtils.isBlank( token )) {
                        log.info( "token is empty ..." );
                        exchange.getResponse().setStatusCode( HttpStatus.UNAUTHORIZED );
                        return exchange.getResponse().setComplete();
                    }
                    return chain.filter(exchange);
                }
            
                @Override
                public int getOrder() {
                    return 0;
                }
            }
 *  Gateway + Nacos [实现动态路由][Link 3] , 参见 [springcloud-demo][]
    
     *  路由信息定义在配置文件中，这种方式有一个缺点就是修改路由信息必须重启服务才能生效。网关作为全部流量的入口，可用时间当然越长越好，不重启服务而修改路由是一个更好的选择，结合Nacos可以做到这一点。在Gateway项目中添加 nacos config 依赖，并配置nacos地址
        
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
            </dependency>
        
            spring.cloud.nacos.config.server-addr=127.0.0.1:8848
 *  Spring Cloud Gateway本身还不支持直接从Nacos动态加载路由配置表，需要自己编写监听器监听配置变化并刷新路由表
 *  方法1：（save和delete方法，供使用gateway-endpoint 访问时 添加和删除路由时使用）
    
        @Component
        public class NacosDynamicRouteService implements ApplicationEventPublisherAware {
            @Override
            public void setApplicationEventPublisher(ApplicationEventPublisher aep) {
                this.applicationEventPublisher = aep;
            }
        
            private ApplicationEventPublisher applicationEventPublisher;
        
            private String dataId = "gateway-router";
            private String group = "DEFAULT_GROUP";
            @Value("${spring.cloud.nacos.config.server-addr}")
            private String serverAddr;
        
            @Autowired
            private RouteDefinitionWriter routeDefinitionWriter;
        
            private static final List<String> ROUTE_LIST = new ArrayList<>();
        
            @PostConstruct
            public void dynamicRouteByNacosListener() {
                try {
                    ConfigService configService = NacosFactory
                         .createConfigService(serverAddr);
        
                    // springboot 启动时，获取配置信息
                    String configInfo = configService.getConfig(dataId, group, 5000);
                    configRouter(configInfo);
                    // 监听 nacos 上的配置文件，当配置文件被修改后，获取配置信息
                    configService.addListener(dataId, group, new Listener() {
                        @Override
                        public void receiveConfigInfo(String configInfo) {
                            configRouter(configInfo);
                        }
        
                        @Override
                        public Executor getExecutor() {
                            return null;
                        }
                    });
                } catch (NacosException e) {
                    e.printStackTrace();
                }
            }
        
            private void configRouter(String configInfo){
                clearRoute();
                try {
                    List<RouteDefinition> gatewayRouteDefinitions = JSONObject.parseArray(
                        configInfo, RouteDefinition.class);
        
                    for (RouteDefinition routeDefinition : gatewayRouteDefinitions) {
                        addRoute(routeDefinition);
                    }
                    publish();
                } catch (Exception 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));
            }
        }
 *  方法2：（仅支持集群环境 各机器同步路由配置，无法根据nacos配置主动更新）
 *      自定义RouteDefinitionWriter
        Spring Cloud Gateway默认的RouteDefinitionWriter实现类是org.springframework.cloud.gateway.route.InMemoryRouteDefinitionRepository，Route信息保存在当前实例的内存中，这在集群环境中会存在同步问题。我们可以自定义一个基于Redis的RouteDefinitionWriter。
        
        import java.util.ArrayList;
        import java.util.List;
        
        import org.springframework.beans.factory.annotation.Autowired;
        import org.springframework.cloud.gateway.route.RouteDefinition;
        import org.springframework.cloud.gateway.route.RouteDefinitionRepository;
        import org.springframework.cloud.gateway.support.NotFoundException;
        import org.springframework.data.redis.core.StringRedisTemplate;
        import org.springframework.stereotype.Component;
        
        import com.alibaba.fastjson.JSON;
        
        import reactor.core.publisher.Flux;
        import reactor.core.publisher.Mono;
        
        /**
         * 使用Redis保存自定义路由配置（代替默认的InMemoryRouteDefinitionRepository）
         * <p/>
         * 存在问题：每次请求都会调用getRouteDefinitions，当网关较多时，会影响请求速度，考虑放到本地Map中，使用消息通知Map更新。
         *
         * @since 2018年7月9日 下午2:39:02
         */
        @Component
        public class RedisRouteDefinitionRepository implements RouteDefinitionRepository {
        
            public static final String  GATEWAY_ROUTES = "geteway_routes";
            @Autowired
            private StringRedisTemplate redisTemplate;
        
            @Override
            public Flux<RouteDefinition> getRouteDefinitions() {
                List<RouteDefinition> routeDefinitions = new ArrayList<>();
                redisTemplate.opsForHash().values(GATEWAY_ROUTES).stream().forEach(routeDefinition -> {
                    routeDefinitions.add(JSON.parseObject(routeDefinition.toString(), RouteDefinition.class));
                });
                return Flux.fromIterable(routeDefinitions);
            }
        
            @Override
            public Mono<Void> save(Mono<RouteDefinition> route) {
                return route
                        .flatMap(routeDefinition -> {
                            redisTemplate.opsForHash().put(GATEWAY_ROUTES, routeDefinition.getId(),
                                    JSON.toJSONString(routeDefinition));
                            return Mono.empty();
                        });
            }
        
            @Override
            public Mono<Void> delete(Mono<String> routeId) {
                return routeId.flatMap(id -> {
                    if (redisTemplate.opsForHash().hasKey(GATEWAY_ROUTES, id)) {
                        redisTemplate.opsForHash().delete(GATEWAY_ROUTES, id);
                        return Mono.empty();
                    }
                    return Mono.defer(() -> Mono.error(new NotFoundException("RouteDefinition not found: " + routeId)));
                });
            }
        
        }
    
     
 *  在 Nacos 管理后台，创建配置文件 gateway-router.json ，内容如下。
    
        [{
            "id": "account-router",
            "order": 0,
            "predicates": [{"args": {"pattern": "/acc/**"},"name": "Path" }],
            "filters":[{"args": {"pattern": true },"name": "Customer" }],
            "uri": "lb://account-service"
        }]
 *  同时删除原来在 application.xml 中关于路由的配置
 *  测试：http://localhost:9001/acc/user?id=2

[Link 1]: https://cloud.spring.io/spring-cloud-static/spring-cloud-gateway/2.2.1.RELEASE/reference/html/#gateway-request-predicates-factories
[gateway]: http://www.itmuch.com/spring-cloud-gateway/spring-cloud-gateway-actuator/
[Gateway_API]: https://www.cnblogs.com/wgslucky/p/11758958.html
[Link 2]: https://yq.aliyun.com/articles/703208
[Filter]: https://cloud.spring.io/spring-cloud-static/spring-cloud-gateway/2.2.1.RELEASE/reference/html/#gateway-how-it-works
[GatewayFilter]: https://cloud.spring.io/spring-cloud-static/spring-cloud-gateway/2.2.1.RELEASE/reference/html/#gatewayfilter-factories
[GlobalFilter]: http://www.itmuch.com/spring-cloud-gateway/global-filter/
[Link 3]: https://blog.csdn.net/autfish/article/details/90752293
[springcloud-demo]: https://github.com/howardhou/SpringBoot/tree/master/springcloud-demo