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springcloud gateway如何实现路由和负载均衡

作者：cuixinzhou　　发布时间：2023-01-09 07:13:35　

标签：springcloud,gateway,路由,负载均衡

简介：

gateway主要是做路由负载，过滤主要是替代zuul 1.x 性能比zuul好 zuul是基于

Servlet ，gateway是基于spring-webflux 用的netty+reactor

yml文件

实现路由负载的配置亲自测试

spring:
application:
name: xgyx_gateway
cloud:
discovery:
locator:
enabled: true
gateway:
routes:
- id: a #随便定义不重复就好
uri: lb://xgyx-welfareservice-x #服务名称
predicates:
- Path=/m/** #前端访问需加入例如 http:ip:port/m
filters:
- StripPrefix=1 #访问后端服务过滤掉m 必填否则找不到后端服务也可以在服务加上统一路径
- name: Hystrix #熔断
args:
name: default
fallbackUri: forward:/defaultfallback #熔断后访问路径
- id: b
uri: lb://xgyx-welfareservice
predicates:
- Path=/welfare/**
filters:
- StripPrefix=1
- name: Hystrix
args:
name: default
fallbackUri: forward:/fallback
#熔断时间
hystrix:
command:
default:
execution:
isolation:
strategy: SEMAPHORE
thread:
timeoutInMilliseconds: 300000 #熔断时间

上面是用了两天时间根据官网上的demo和说明自己测的可以使用上面 stripPrefix 用的是 PrefixPath 过滤器其他过滤器使用可以看官网

springcloud gateway 自定义负载均衡

相关类及接口

LoadbalancerClientFilter：使用ribbon负载均衡，默认使用该类（已不推荐使用）

/** @deprecated */
@Deprecated
public class LoadBalancerClientFilter implements GlobalFilter, Ordered {
public static final int LOAD_BALANCER_CLIENT_FILTER_ORDER = 10100;
private static final Log log = LogFactory.getLog(LoadBalancerClientFilter.class);
protected final LoadBalancerClient loadBalancer;
private LoadBalancerProperties properties;

public LoadBalancerClientFilter(LoadBalancerClient loadBalancer, LoadBalancerProperties properties) {
this.loadBalancer = loadBalancer;
this.properties = properties;
}

public int getOrder() {
return 10100;
}

public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
URI url = (URI)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR);
String schemePrefix = (String)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR);
if (url != null && ("lb".equals(url.getScheme()) || "lb".equals(schemePrefix))) {
ServerWebExchangeUtils.addOriginalRequestUrl(exchange, url);
if (log.isTraceEnabled()) {
log.trace("LoadBalancerClientFilter url before: " + url);
}

ServiceInstance instance = this.choose(exchange);
if (instance == null) {
throw NotFoundException.create(this.properties.isUse404(), "Unable to find instance for " + url.getHost());
} else {
URI uri = exchange.getRequest().getURI();
String overrideScheme = instance.isSecure() ? "https" : "http";
if (schemePrefix != null) {
overrideScheme = url.getScheme();
}

URI requestUrl = this.loadBalancer.reconstructURI(new DelegatingServiceInstance(instance, overrideScheme), uri);
if (log.isTraceEnabled()) {
log.trace("LoadBalancerClientFilter url chosen: " + requestUrl);
}

exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR, requestUrl);
return chain.filter(exchange);
}
} else {
return chain.filter(exchange);
}
}

protected ServiceInstance choose(ServerWebExchange exchange) {
return this.loadBalancer.choose(((URI)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR)).getHost());
}
}

说明：默认使用该类，可通过下述方法使用ReactiveLoadbalancerClientFilter

"You already have RibbonLoadBalancerClient on your classpath. It will be used by default.
As Spring Cloud Ribbon is in maintenance mode. We recommend switching to " + BlockingLoadBalancerClient.class.getSimpleName() + " instead.
In order to use it, set the value of `spring.cloud.loadbalancer.ribbon.enabled` to `false`
or remove spring-cloud-starter-netflix-ribbon from your project."

ReactiveLoadBalancerClientFilter：负载均衡 *

public class ReactiveLoadBalancerClientFilter implements GlobalFilter, Ordered {
private static final Log log = LogFactory.getLog(ReactiveLoadBalancerClientFilter.class);
private static final int LOAD_BALANCER_CLIENT_FILTER_ORDER = 10150;
private final LoadBalancerClientFactory clientFactory;
private LoadBalancerProperties properties;
public ReactiveLoadBalancerClientFilter(LoadBalancerClientFactory clientFactory, LoadBalancerProperties properties) {
this.clientFactory = clientFactory;
this.properties = properties;
}

public int getOrder() {
return 10150;
}

public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
URI url = (URI)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR);
String schemePrefix = (String)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR);
if (url != null && ("lb".equals(url.getScheme()) || "lb".equals(schemePrefix))) {
//url不为null且协议为lb，或者url以lb开头

ServerWebExchangeUtils.addOriginalRequestUrl(exchange, url);
if (log.isTraceEnabled()) {
log.trace(ReactiveLoadBalancerClientFilter.class.getSimpleName() + " url before: " + url);
}

return this.choose(exchange).doOnNext((response) -> {
//获取ServiceInstance实例，进行一些处理

if (!response.hasServer()) {
//如果没有serviceInstance，直接抛出异常

throw NotFoundException.create(this.properties.isUse404(), "Unable to find instance for " + url.getHost());
} else { //如果有serviceInstance，进行相关处理
URI uri = exchange.getRequest().getURI();
String overrideScheme = null;
if (schemePrefix != null) {
overrideScheme = url.getScheme();
}

DelegatingServiceInstance serviceInstance = new DelegatingServiceInstance((ServiceInstance)response.getServer(), overrideScheme);
URI requestUrl = LoadBalancerUriTools.reconstructURI(serviceInstance, uri);
if (log.isTraceEnabled()) {
log.trace("LoadBalancerClientFilter url chosen: " + requestUrl);
}

exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR, requestUrl);
}
}).then(chain.filter(exchange));
} else {
return chain.filter(exchange); //如果获取不到serviceInstance，直接进行后续过滤
}
}

private Mono<Response<ServiceInstance>> choose(ServerWebExchange exchange) {
URI uri = (URI)exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR);
ReactorLoadBalancer<ServiceInstance> loadBalancer = (ReactorLoadBalancer)this.clientFactory.getInstance(uri.getHost(), ReactorLoadBalancer.class, new Class[]{ServiceInstance.class});
if (loadBalancer == null) {
throw new NotFoundException("No loadbalancer available for " + uri.getHost());
} else {
return loadBalancer.choose(this.createRequest());
}
}//选择服务实例

private Request createRequest() {
return ReactiveLoadBalancer.REQUEST;
}
}

ReactorLoadBalancer：负载均衡接口

public interface ReactorLoadBalancer<T> extends ReactiveLoadBalancer<T> {
Mono<Response<T>> choose(Request request);
default Mono<Response<T>> choose() {
return this.choose(REQUEST);
}
}
***********************
public interface ReactorServiceInstanceLoadBalancer extends ReactorLoadBalancer<ServiceInstance> {
}

RoundRobinLoadbalancer：负载均衡使用轮询

public class RoundRobinLoadBalancer implements ReactorServiceInstanceLoadBalancer {
private static final Log log = LogFactory.getLog(RoundRobinLoadBalancer.class);
private final AtomicInteger position;
private ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider;
private final String serviceId;

************
构造方法

public RoundRobinLoadBalancer(ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider, String serviceId) {
public RoundRobinLoadBalancer(ObjectProvider<ServiceInstanceListSupplier> serviceInstanceListSupplierProvider, String serviceId, int seedPosition) {

************
普通方法

public Mono<Response<ServiceInstance>> choose(Request request) {
if (this.serviceInstanceListSupplierProvider != null) {
ServiceInstanceListSupplier supplier = (ServiceInstanceListSupplier)this.serviceInstanceListSupplierProvider.getIfAvailable(NoopServiceInstanceListSupplier::new);
return ((Flux)supplier.get()).next().map(this::getInstanceResponse);
} else {
ServiceInstanceSupplier supplier = (ServiceInstanceSupplier)this.serviceInstanceSupplier.getIfAvailable(NoopServiceInstanceSupplier::new);
return ((Flux)supplier.get()).collectList().map(this::getInstanceResponse);
}
}

private Response<ServiceInstance> getInstanceResponse(List<ServiceInstance> instances) {
if (instances.isEmpty()) {
log.warn("No servers available for service: " + this.serviceId);
return new EmptyResponse();
} else {
int pos = Math.abs(this.position.incrementAndGet());
ServiceInstance instance = (ServiceInstance)instances.get(pos ％ instances.size());
return new DefaultResponse(instance);
}
}//使用轮询获取实例
}

示例：

参数id为偶数时，输出hello new version

网关

配置文件

spring:
application:
name: hello-gateway
cloud:
consul:
host: 172.18.0.20
port: 8500
loadbalancer:
ribbon:
enabled: false
gateway:
routes:
- id: myRoute
uri: lb://hello-service
predicates:
- Path=/hello

自定义过滤器

@Component
public class CustomLoadBalancerClientFilter implements GlobalFilter, Ordered {
private static final Log log = LogFactory.getLog(org.springframework.cloud.gateway.filter.ReactiveLoadBalancerClientFilter.class);

@Resource
private final LoadBalancerClientFactory clientFactory;

@Resource
private LoadBalancerProperties properties;

public CustomLoadBalancerClientFilter(LoadBalancerClientFactory clientFactory, LoadBalancerProperties properties) {
this.clientFactory = clientFactory;
this.properties = properties;
}

public int getOrder() {
return 10149;
}

public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
URI url = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR);
String schemePrefix = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_SCHEME_PREFIX_ATTR);
if (url != null && ("lb".equals(url.getScheme()) || "lb".equals(schemePrefix))) {
ServerWebExchangeUtils.addOriginalRequestUrl(exchange, url);
if (log.isTraceEnabled()) {
log.trace(ReactiveLoadBalancerClientFilter.class.getSimpleName() + " url before: " + url);
}

return this.choose(exchange).doOnNext((response) -> {
if (!response.hasServer()) {
throw NotFoundException.create(this.properties.isUse404(), "Unable to find instance for " + url.getHost());
} else {
URI uri = exchange.getRequest().getURI();
String overrideScheme = null;
if (schemePrefix != null) {
overrideScheme = url.getScheme();
}

int id=Integer.parseInt(Objects.requireNonNull(exchange.getRequest().getQueryParams().getFirst("id")));
if (id％2==0){
while (!"new".equals(response.getServer().getMetadata().get("version"))){
try {
response=this.choose(exchange).toFuture().get();
}catch (Exception e){
System.out.println(e.getMessage());
}
}
}

DelegatingServiceInstance serviceInstance = new DelegatingServiceInstance(response.getServer(), overrideScheme);

System.out.println(exchange.getRequest().getQueryParams().getFirst("id")+"对应server的version为："+serviceInstance.getMetadata().get("version"));
URI requestUrl = LoadBalancerUriTools.reconstructURI(serviceInstance, uri);
if (log.isTraceEnabled()) {
log.trace("LoadBalancerClientFilter url chosen: " + requestUrl);
}

exchange.getAttributes().put(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR, requestUrl);
}
}).then(chain.filter(exchange));
} else {
return chain.filter(exchange);
}
}

private Mono<Response<ServiceInstance>> choose(ServerWebExchange exchange) {
URI uri = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_REQUEST_URL_ATTR);
assert uri != null;
ReactorLoadBalancer<ServiceInstance> loadBalancer = this.clientFactory.getInstance(uri.getHost(), ReactorLoadBalancer.class, new Class[]{ServiceInstance.class});
if (loadBalancer == null) {
throw new NotFoundException("No loadbalancer available for " + uri.getHost());
} else {
return loadBalancer.choose(this.createRequest());
}
}

private Request createRequest() {
return ReactiveLoadBalancer.REQUEST;
}
}

同名应用hello-service1

配置文件

spring:
application:
name: hello-service
cloud:
consul:
host: 172.18.0.20
port: 8500
discovery:
instance-id: ${spring.application.name}-${random.int}
tags: version=old

controller 层

@RestController
public class HelloController {
@RequestMapping("/hello")
public String hello(){
return "hello old version";
}
}

同名应用hello-service2

配置文件

spring:
application:
name: hello-service
cloud:
consul:
host: 172.18.0.20
port: 8500
discovery:
instance-id: ${spring.application.name}-${random.int}
tags: version=new

controller 层