springcloud gateway怎么实现路由和负载均衡

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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@Deprecatedpublic 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：负载均衡拦截器

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

@Componentpublic 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

@RestControllerpublic 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

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

测试输出

consul注册的应用

参数测试

当id为偶数时，输出为hello new version

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