Spring Cloud Gateway简单入门，强大的微服务网关
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Spring Cloud Gateway是用于微服务场景的网关组件，它是基于Spring WebFlux，也就是Reactive的。从实现原理上，它的性能应该是比Zuul会更好。它的工作原理如下图所示：
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简单而言就是通过一连串的
Filter处理匹配到特定规则Predicates的请求。所以最主要就是做了两件事：（1）哪些请求可以被它处理，由
Predicates决定；（2）如何处理，由
Filters决定。2 路由条件判断Predicates 2.1 时间匹配After 表示在什么时间之后才算满足条件匹配路由：
spring:
cloud:
gateway:
routes:
- id: after_route
uri: https://example.org
predicates:
- After=2020-01-20T17:42:47.789-07:00[America/Denver]2.2 时间匹配Before 表示在什么时间之前匹配路由：
spring:
cloud:
gateway:
routes:
- id: before_route
uri: https://example.org
predicates:
- Before=2017-01-20T17:42:47.789-07:00[America/Denver]2.3 时间段匹配Between 表示在什么时间段匹配路由：
spring:
cloud:
gateway:
routes:
- id: between_route
uri: https://example.org
predicates:
- Between=2017-01-20T17:42:47.789-07:00[America/Denver], 2017-01-21T17:42:47.789-07:00[America/Denver]2.4 Cookie匹配 表示通过判断
Cookie的键值来匹配路由，其中值支持正则表达式：spring:
cloud:
gateway:
routes:
- id: cookie_route
uri: https://example.org
predicates:
- Cookie=chocolate, ch.p2.5 请求头匹配Header 表示通过判断
Http请求的Header来匹配路由：spring:
cloud:
gateway:
routes:
- id: header_route
uri: https://example.org
predicates:
- Header=X-Request-Id, \d+2.6 主机名匹配Host 通过判断
Hostname来匹配路由：spring:
cloud:
gateway:
routes:
- id: host_route
uri: https://example.org
predicates:
- Host=**.somehost.org,**.anotherhost.org2.7 请求方法匹配Method 表示通过判断请求方法来匹配路由：
spring:
cloud:
gateway:
routes:
- id: method_route
uri: https://example.org
predicates:
- Method=GET,POST2.8 请求路径匹配Path 表示通过判断请求路径来匹配路由，很常用：
spring:
cloud:
gateway:
routes:
- id: path_route
uri: https://example.org
predicates:
- Path=/red/{segment},/blue/{segment}2.9 请求参数匹配Query 表示通过判断请求参数来匹配路由：
spring:
cloud:
gateway:
routes:
- id: query_route
uri: https://example.org
predicates:
- Query=red, gree.2.10 IP地址匹配RemoteAddr 表示通过判断
IP地址来匹配路由：spring:
cloud:
gateway:
routes:
- id: remoteaddr_route
uri: https://example.org
predicates:
- RemoteAddr=192.168.1.1/242.11 权重匹配Weight 通过权重来匹配路由：
spring:
cloud:
gateway:
routes:
- id: weight_high
uri: https://weighthigh.org
predicates:
- Weight=group1, 8
- id: weight_low
uri: https://weightlow.org
predicates:
- Weight=group1, 23 功能强大的GatewayFilter
Spring提供许多强大的GatewayFilter对请求进行处理。3.1 添加请求头 给请求添加
Header：spring:
cloud:
gateway:
routes:
- id: add_request_header_route
uri: https://example.org
predicates:
- Path=/red/{segment}
filters:
- AddRequestHeader=X-Request-Red, Blue-{segment}3.2 添加请求参数
spring:
cloud:
gateway:
routes:
- id: add_request_parameter_route
uri: https://example.org
predicates:
- Host: {segment}.myhost.org
filters:
- AddRequestParameter=foo, bar-{segment}3.3 添加返回Header
spring:
cloud:
gateway:
routes:
- id: add_response_header_route
uri: https://example.org
predicates:
- Host: {segment}.myhost.org
filters:
- AddResponseHeader=foo, bar-{segment}3.4 删除重复返回Header
spring:
cloud:
gateway:
routes:
- id: dedupe_response_header_route
uri: https://example.org
filters:
- DedupeResponseHeader=Access-Control-Allow-Credentials Access-Control-Allow-Origin3.5 断路器Hystrix 简单配置：
spring:
cloud:
gateway:
routes:
- id: hystrix_route
uri: https://example.org
filters:
- Hystrix=myCommandName较复杂配置：
spring:
cloud:
gateway:
routes:
- id: hystrix_route
uri: lb://backing-service:8088
predicates:
- Path=/consumingserviceendpoint
filters:
- name: Hystrix
args:
name: fallbackcmd
fallbackUri: forward:/incaseoffailureusethis
- RewritePath=/consumingserviceendpoint, /backingserviceendpoint3.6 断路器CircuitBreaker 简单配置：
spring:
cloud:
gateway:
routes:
- id: circuitbreaker_route
uri: https://example.org
filters:
- CircuitBreaker=myCircuitBreaker较复杂配置：
spring:
cloud:
gateway:
routes:
- id: circuitbreaker_route
uri: lb://backing-service:8088
predicates:
- Path=/consumingServiceEndpoint
filters:
- name: CircuitBreaker
args:
name: myCircuitBreaker
fallbackUri: forward:/inCaseOfFailureUseThis
- RewritePath=/consumingServiceEndpoint, /backingServiceEndpoint3. 7 请求头改名
spring:
cloud:
gateway:
routes:
- id: map_request_header_route
uri: https://example.org
filters:
- MapRequestHeader=Blue, X-Request-Red3.8 路径添加前缀 这个要注意和匹配路径区分，它是在匹配后再加个前缀：
spring:
cloud:
gateway:
routes:
- id: prefixpath_route
uri: https://example.org
filters:
- PrefixPath=/mypath请求
/hello变成/mypath/hello。3.9 重定向
spring:
cloud:
gateway:
routes:
- id: prefixpath_route
uri: https://example.org
filters:
- RedirectTo=302, https://acme.org3.10 删除请求头
spring:
cloud:
gateway:
routes:
- id: removerequestheader_route
uri: https://example.org
filters:
- RemoveRequestHeader=X-Request-Foo3.11 删除返回头
spring:
cloud:
gateway:
routes:
- id: removeresponseheader_route
uri: https://example.org
filters:
- RemoveResponseHeader=X-Response-Foo3.12 删除请求参数
spring:
cloud:
gateway:
routes:
- id: removerequestparameter_route
uri: https://example.org
filters:
- RemoveRequestParameter=red3.13 重写路径
spring:
cloud:
gateway:
routes:
- id: rewritepath_route
uri: https://example.org
predicates:
- Path=/red/**
filters:
- RewritePath=/red(?/?.*), $\{segment}3.14 设置路径
spring:
cloud:
gateway:
routes:
- id: setpath_route
uri: https://example.org
predicates:
- Path=/red/{segment}
filters:
- SetPath=/{segment}3.15 设置请求头
spring:
cloud:
gateway:
routes:
- id: setrequestheader_route
uri: https://example.org
predicates:
- Host: {segment}.myhost.org
filters:
- SetRequestHeader=foo, bar-{segment}3.16 设置返回头
spring:
cloud:
gateway:
routes:
- id: setresponseheader_route
uri: https://example.org
predicates:
- Host: {segment}.myhost.org
filters:
- SetResponseHeader=foo, bar-{segment}3.17 设置返回状态码
spring:
cloud:
gateway:
routes:
- id: setstatusstring_route
uri: https://example.org
filters:
- SetStatus=BAD_REQUEST
- id: setstatusint_route
uri: https://example.org
filters:
- SetStatus=4013.18 去掉路径前缀
spring:
cloud:
gateway:
routes:
- id: nameRoot
uri: https://nameservice
predicates:
- Path=/name/**
filters:
- StripPrefix=2这配置请求
/name/blue/red，实际就是请求nameservice的/red，去掉两个前缀。3.19 重试Retry
GatewayFilter
想不到居然还有强大的重试功能：spring:
cloud:
gateway:
routes:
- id: retry_test
uri: http://localhost:8080/flakey
predicates:
- Host=*.retry.com
filters:
- name: Retry
args:
retries: 3
statuses: BAD_GATEWAY
methods: GET,POST
backoff:
firstBackoff: 10ms
maxBackoff: 50ms
factor: 2
basedOnPreviousValue: false3.20 请求大小限制
spring:
cloud:
gateway:
routes:
- id: request_size_route
uri: http://localhost:8080/upload
predicates:
- Path=/upload
filters:
- name: RequestSize
args:
maxSize: 50000003.21 默认Filter 如果希望对所有路由都生效，可以添加默认
Filter：spring:
cloud:
gateway:
default-filters:
- AddResponseHeader=X-Response-Default-Red, Default-Blue
- PrefixPath=/httpbin4 全局Global Filters 全局过滤器
GlobalFilter接口和GatewayFilter的方法是一样的，但它是用于所有路由的。当请求过来时，整个Filter Chain是包含了所有的GlobalFilters和匹配上的GatewayFilters，执行顺序由getOrder()方法决定。如下：
@Bean
public GlobalFilter customFilter() {
return new CustomGlobalFilter();
}public class CustomGlobalFilter implements GlobalFilter, Ordered {@Override
public Mono filter(ServerWebExchange exchange, GatewayFilterChain chain) {
log.info("custom global filter");
return chain.filter(exchange);
}@Override
public int getOrder() {
return -1;
}
} 5 一切皆可自定义
Spring支持开发人员自定义Predicate、GatewayFilter和GlobalFilter。5.1 自定义Predicate
public class MyRoutePredicateFactory extends AbstractRoutePredicateFactory {public MyRoutePredicateFactory() {
super(Config.class);
}@Override
public Predicate apply(Config config) {
// grab configuration from Config object
return exchange -> {
//grab the request
ServerHttpRequest request = exchange.getRequest();
//take information from the request to see if it
//matches configuration.
return matches(config, request);
};
}public static class Config {
//Put the configuration properties for your filter here
}
}5.2 自定义GatewayFilter
Pre的过滤器：public class PreGatewayFilterFactory extends AbstractGatewayFilterFactory {public PreGatewayFilterFactory() {
super(Config.class);
}@Override
public GatewayFilter apply(Config config) {
// grab configuration from Config object
return (exchange, chain) -> {
//If you want to build a "pre" filter you need to manipulate the
//request before calling chain.filter
ServerHttpRequest.Builder builder = exchange.getRequest().mutate();
//use builder to manipulate the request
return chain.filter(exchange.mutate().request(builder.build()).build());
};
}public static class Config {
//Put the configuration properties for your filter here
}
}
Post的过滤器：public class PostGatewayFilterFactory extends AbstractGatewayFilterFactory {public PostGatewayFilterFactory() {
super(Config.class);
}@Override
public GatewayFilter apply(Config config) {
// grab configuration from Config object
return (exchange, chain) -> {
return chain.filter(exchange).then(Mono.fromRunnable(() -> {
ServerHttpResponse response = exchange.getResponse();
//Manipulate the response in some way
}));
};
}public static class Config {
//Put the configuration properties for your filter here
}
}5.3 自定义GlobalFilter
@Bean
public GlobalFilter customGlobalFilter() {
return (exchange, chain) -> exchange.getPrincipal()
.map(Principal::getName)
.defaultIfEmpty("Default User")
.map(userName -> {
//adds header to proxied request
exchange.getRequest().mutate().header("CUSTOM-REQUEST-HEADER", userName).build();
return exchange;
})
.flatMap(chain::filter);
}@Bean
public GlobalFilter customGlobalPostFilter() {
return (exchange, chain) -> chain.filter(exchange)
.then(Mono.just(exchange))
.map(serverWebExchange -> {
//adds header to response
serverWebExchange.getResponse().getHeaders().set("CUSTOM-RESPONSE-HEADER",
HttpStatus.OK.equals(serverWebExchange.getResponse().getStatusCode()) ? "It worked": "It did not work");
return serverWebExchange;
})
.then();
}6 项目使用 添加依赖：
org.springframework.cloud
spring-cloud-starter-gateway
配置Main启动应用：
package com.pkslow.cloud.gateway;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class GatewayService {
public static void main(String[] args) {
SpringApplication.run(GatewayService.class, args);
}
}配置路由：
server:
port: 8080
spring:
cloud:
gateway:
routes:
- id: pkslow
uri: https://www.pkslow.com
predicates:
- Path=/pkslow/**
filters:
- RewritePath=/pkslow(?.*), /$\{segment}启动后可正常访问了：
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7 总结
Spring Cloud Gateway实在是非常强大，能满足微服务绝大多数应用场景了，还是很有必要了解一下的。代码请查看：https://github.com/LarryDpk/p...
参考资料：官网
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【Spring Cloud Gateway简单入门，强大的微服务网关】多读书，多分享；多写作，多整理。
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