Spring Cloud Gateway根据CPU的使用情况限流

<dependencies>
    <!-- Spring Cloud Gateway的依赖-->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-gateway</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
</dependencies>

@SpringBootApplication
public class GatewayApplication {

    @Autowired
    private GatewayRateLimitFilterByCpu gatewayRateLimitFilterByCpu;

    @Bean
    public RouteLocator customerRouteLocator(RouteLocatorBuilder builder) {
        return builder.routes()
                .route(r -> r.path("/test/rateLimit")
                        .filters(f -> f.filter(gatewayRateLimitFilterByCpu))
                        .uri("http://localhost:8000/hello/rateLimit")
                        .id("rateLimit_route")
                ).build();
    }
    public static void main(String[] args) {
        SpringApplication.run(GatewayApplication.class, args);
    }
}

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.actuate.metrics.MetricsEndpoint;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.core.Ordered;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

import java.util.Objects;

/**
 * 根据CPU的使用情况限流
 * @author yezhou
 */
@Slf4j
@Component
public class GatewayRateLimitByCpuFilter implements GatewayFilter, Ordered {

    @Autowired
    private MetricsEndpoint metricsEndpoint;

    private static final String METRIC_NAME = "system.cpu.usage";

    private static final double MAX_USAGE = 0.50D;

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        //获取网关所在机器的CPU使用情况
        Double systemCpuUsage = metricsEndpoint.metric(METRIC_NAME, null)
                .getMeasurements()
                .stream()
                .filter(Objects::nonNull)
                .findFirst()
                .map(MetricsEndpoint.Sample::getValue)
                .filter(Double::isFinite)
                .orElse(0.0D);

        boolean isOpenRateLimit = systemCpuUsage > MAX_USAGE;
        log.debug("system.cpu.usage: {}, isOpenRateLimit:{} ", systemCpuUsage, isOpenRateLimit);
        if (isOpenRateLimit) {
            //当CPU的使用超过设置的最大阀值开启限流
            exchange.getResponse().setStatusCode(HttpStatus.TOO_MANY_REQUESTS);
            return exchange.getResponse().setComplete();
        } else {
            return chain.filter(exchange);
        }
    }

    @Override
    public int getOrder() {
        return 0;
    }
}