SpringCloud Gateway 服务网关，限流

SpringCloud Gateway 提供了基于Redis 和lua脚本实现的令牌桶算法进行限流，即 RequestRateLimiterGatewayFilterFactory类，通过设置过滤器实现限流。

1、maven依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis-reactive</artifactId>
</dependency>

2、服务网关完整的配置文件如下

server:
  port: 8801
spring:
  application:
    name: gateway
  cloud:
    consul:
      host: localhost
      port: 8500
      discovery:
        service-name: gateway
    gateway:
      discovery:
        locator:
          enabled: false
          lower-case-service-id: true
      routes:
        - id: logservice
          uri: lb://logservice
          predicates:
          - Path=/log/**
          filters:
          - StripPrefix=1
        - id: orderservice
          uri: lb://orderservice
          predicates:
            - Path=/order/**
            - Method=GET
          filters:
            - StripPrefix=1
            - name: RequestRateLimiter
              args:
                # #{@beanName} 限流key, bean对象名称，实现KeyResolver接口resolve方法的类对象。
                key-resolver: "#{@urlKeyResolver}"
                # 令牌桶每秒填充10个令牌
                redis-rate-limiter.replenishRate: 10
                # 突发20个
                redis-rate-limiter.burstCapacity: 50
                # 每次请求消耗1个
                redis-rate-limiter.requestedTokens: 1
  redis:
    host: localhost
    port: 6379
    database: 8

# 配置日志
logging:
  level:
    org.springframework.cloud.gateway: debug

3、KeyResolver 针对接口进行限流

@Component
public class KeyResolverConfig {
    /**
     * 根据Url进行限流
     */
    @Bean
    public KeyResolver urlKeyResolver() {
        return exchange -> Mono.just(exchange.getRequest().getURI().getPath());
    }
}

4、使用jmeter进行压测，20秒发送300个请求，get方式进行http请求，

http://localhost:8801/order/order

5、查看服务网关控制台日志里

成功转发的信息如下：

ratelimit.RedisRateLimiter     : response: Response{allowed=true, headers={X-RateLimit-Remaining=23, X-RateLimit-Requested-Tokens=1, X-RateLimit-Burst-Capacity=50, X-RateLimit-Replenish-Rate=10}, tokensRemaining=-1}

失败的信息：

response: Response{allowed=false, headers={X-RateLimit-Remaining=0, X-RateLimit-Requested-Tokens=1, X-RateLimit-Burst-Capacity=50, X-RateLimit-Replenish-Rate=10}, tokensRemaining=-1}

失败的大约有60个。