Add the function of collecting resource utilization metrics for extension services.

[Yuukadesu]

Purpose

By using JAVA packages like java.lang.management to collect service load data and report it, provide data support for the operation of load balancer。

Programs

Add Usage Class
Used to represent the usage of memory and CPU, and provides the percentUsage() method to calculate the percentage of resources.

public Usage(double usage, double limit) {
    this.usage = usage;
    this.limit = limit;
}

public float percentUsage() {
        float proportion = 0;
        if (limit > 0) {
           proportion = ((float) usage) / ((float) limit);
        }
        return proportion * 100;
    }

Add ServiceLoadDataReport Class and ServiceLoadDataReportGenerator Class
The ServiceLoadDataReport class is used to represent ServiceLoadData, while the ServiceLoadDataReportGenerator enables threads to periodically retrieve data and report it.

public ServiceLoadDataReport(Usage CPU, Usage memory, int weight) {
        this.CPU = CPU;
        Memory = memory;
        Weight = weight;
    }

static {
        executorService = Executors.newSingleThreadScheduledExecutor();
        systemBean = (OperatingSystemMXBean) ManagementFactory.getOperatingSystemMXBean();
        serviceLoadDataReport = new ServiceLoadDataReport();
        totalCPULimit = getTotalCPULimit();
        calculateUsage();
        executorService.scheduleWithFixedDelay(ServiceLoadDataReportGenerator::checkCPULoad, CPU_CHECK_MILLIS, CPU_CHECK_MILLIS, TimeUnit.MILLISECONDS);
        executorService.scheduleWithFixedDelay(ServiceLoadDataReportGenerator::doCalculateUsage, 1, 1, TimeUnit.MINUTES);
        executorService.scheduleWithFixedDelay(ServiceLoadDataReportGenerator::doCalculateMemoryUsage, 1, 1, TimeUnit.MINUTES);
    }