spring cloud gateway

spring cloud gateway未来第二代网关，基于Netty，Reactor以及WefFlux构建

性能zuul的1.6倍，功能强大内置了很多实用功能，比如转发，监控，限流等。不是Servlet编程模型，有一定的适应成本，不在Servlet容器下工作，不能打成war包，不支持springboot1.XX

使用gateway

1、添加依赖

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

2、写注解

3、写配置

spring:
  application:
    name: gateway
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848
        namespace: cf734626-9b65-411f-a77a-1fc14869fd05
    gateway:
      discovery:
        locator:
          enabled: true
server:
  port: 8088
management:
  endpoints:
    web:
      exposure:
        include: '*'
  endpoint:
    health:
      show-details: always

核心概念
Route
　　Spring cloud gateway的基础元素，可简单的理解成一条转发规则，包含ID，目标URL，Predicate集合以及Filter集合
Predicate
　　即java.util.function.Predicate,Spring Cloud Gateway使用Predicate实现路由的条件
Filter
　　修改请求及相应
路由配置详解参见
https://www.imooc.com/article/290804

自定义谓词工厂

package com.fj.xiaofeiyang.gateway.predicate;

import org.springframework.cloud.gateway.handler.predicate.AbstractRoutePredicateFactory;
import org.springframework.web.server.ServerWebExchange;

import java.time.LocalTime;
import java.util.Arrays;
import java.util.List;
import java.util.function.Predicate;

/**
 * @author: yangchun
 * @description:
 * @date: Created in 2020-02-29 9:57
 */
public class TimeBetweenPredicateFactory extends AbstractRoutePredicateFactory<TimeBetweenConfig> {
    public TimeBetweenPredicateFactory() {
        super(TimeBetweenConfig.class);
    }

    @Override
    public List<String> shortcutFieldOrder() {
        return Arrays.asList("start","end");
    }

    @Override
    public Predicate<ServerWebExchange> apply(TimeBetweenConfig config) {
        LocalTime start = config.getStart();
        LocalTime end = config.getEnd();
        return serverWebExchange -> {
            LocalTime now = LocalTime.now();
            return now.isAfter(start)&&now.isBefore(end);
        };
    }
}

配置

spring:
  application:
    name: gateway
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848
        namespace: cf734626-9b65-411f-a77a-1fc14869fd05
    gateway:
      discovery:
        locator:
          enabled: true
      routes:
        - id: after_route
          uri: lb://pay
          predicates:
            - After=2030-01-20T17:42:47.789-07:00[America/Denver]
            - TimeBetween=9:00,17:00

过滤器工厂详情解析，功能可以添加请求头
https://www.imooc.com/article/290816
自定义过滤器工厂生命周期pre转发前，post就是转发后

自定义过滤器工厂

继承：AbstractGatewayFilterFactory
参考示例：org.springframework.cloud.gateway.filter.factory.RequestSizeGatewayFilterFactory

配置形式

gateway:
  discovery:
    locator:
      enabled: true
  routes:
    - id: after_route
      uri: lb://pay
      predicates:
        - After=2030-01-20T17:42:47.789-07:00[America/Denver]
        - TimeBetween=9:00,17:00
      filters:
        - name: RequestSize
          args:
            maxSize: 5000000

继承：AbstractNameValueGatewayFilterFactory
参考示例：org.springframework.cloud.gateway.filter.factory.AddRequestHeaderGatewayFilterFactory

配置

gateway:
  discovery:
    locator:
      enabled: true
  routes:
    - id: after_route
      uri: lb://pay
      predicates:
        - After=2030-01-20T17:42:47.789-07:00[America/Denver]
        - TimeBetween=9:00,17:00
      filters:
        - AddRequestHeader=X-Request-Foo, Bar

自定义过滤器工厂-核心API
exchange.getRequest().mutate().xxx修改request
exchange.mutate().xxx修改exchange
chain.filter(exchange)传递给下一个过滤器
exchange.getResponse()

过滤器工厂详情解析，功能可以添加请求头
https://www.imooc.com/article/290821


Spring cloud gateway actuator监控

https://www.imooc.com/article/290822

Spring cloud gateway 问题排错

https://www.imooc.com/article/290824

集群限流

https://www.imooc.com/article/290828