PIOT-GDA-02-007: Connect SystemCpuUtilTask and SystemMemUtilTask to SystemPerformanceManager

[labbenchstudios]

Description

• Connect SystemCpuUtilTask and SystemMemUtilTask into SystemPerformanceManager by invoking their respective getTelemetryValue() methods within the SystemPerformanceManager method called handleTelemetry() using a scheduled thread. This work should be implemented within the SystemPerformanceManager class.

Review the README

• Please see README.md for further information on, and use of, this content.
• License for embedded documentation and source codes: PIOT-DOC-LIC

Estimated effort may vary greatly

• The estimated level of effort for this exercise shown in the 'Estimate' section below is a very rough approximation. The actual level of effort may vary greatly depending on your development and test environment, experience with the requisite technologies, and many other factors.

Actions

NOTE: The implementation examples depicted here are only one way to implement the requirements listed. Your own implementation may vary of course.

• Add the following import statements:

import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;

• Add the following members to the class:

private ScheduledExecutorService schedExecSvc = null;
private SystemCpuUtilTask sysCpuUtilTask = null;
private SystemMemUtilTask sysMemUtilTask = null;

private Runnable taskRunner = null;
private boolean isStarted = false;

• Create a public method named 'handleTelemetry()' that includes the calls to retrieve the CPU and Memory utilization (again, these may not function properly on every OS).
• Log either an information or debug / fine-grained message that includes the values of cpuUtil and memUtil.

public void handleTelemetry()
{
	float cpuUtil = this.sysCpuUtilTask.getTelemetryValue();
	float memUtil = this.sysMemUtilTask.getTelemetryValue();
	
	_Logger.fine("CPU utilization: " + cpuUtil + ", Mem utilization: " + memUtil);
}

• Within the constructor, create the instances of SystemCpuUtilTask and SystemMemUtilTask, as well as the scheduler service to handle interval-based calling to retrieve each task's value:

public SystemPerformanceManager()
{
	this.pollRate =
		ConfigUtil.getInstance().getInteger(
			ConfigConst.GATEWAY_DEVICE, ConfigConst.POLL_CYCLES_KEY, ConfigConst.DEFAULT_POLL_CYCLES);
	
	if (this.pollRate <= 0) {
		this.pollRate = ConfigConst.DEFAULT_POLL_CYCLES;
	}
	
	this.schedExecSvc   = Executors.newScheduledThreadPool(1);
	this.sysCpuUtilTask = new SystemCpuUtilTask();
	this.sysMemUtilTask = new SystemMemUtilTask();
	
	this.taskRunner = () -> {
		this.handleTelemetry();
	};
}

• Update the startManager() method, invoke the this.schedExecSvc.scheduleAtFixedRate() method to start the scheduler.

public boolean startManager()
{
	if (! this.isStarted) {
		_Logger.info("SystemPerformanceManager is starting...");
		
		ScheduledFuture<?> futureTask =
			this.schedExecSvc.scheduleAtFixedRate(this.taskRunner, 1L, this.pollRate, TimeUnit.SECONDS);
		
		this.isStarted = true;
	} else {
		_Logger.info("SystemPerformanceManager is already started.");
	}
	
	return this.isStarted;
}

• Within the stopManager() method, invoke the this.schedExecSvc.shutdown(); call to stop the scheduler.

public boolean stopManager()
{
	this.schedExecSvc.shutdown();
	this.isStarted = false;
	
	_Logger.info("SystemPerformanceManager is stopped.");
	
	return true;
}

Estimate

• Medium

Tests

• Integration tests (in ./src/test/java/programmingtheiot/part01/integration)
  • Run ./app/GatewayDeviceAppTest. Integration test should pass and generate output similar to the following:

Jul 19, 2020 1:53:19 PM programmingtheiot.gda.app.GatewayDeviceApp <init>
INFO: Initializing GDA...
Jul 19, 2020 1:53:19 PM programmingtheiot.gda.app.GatewayDeviceApp parseArgs
INFO: No command line args to parse.
Jul 19, 2020 1:53:19 PM programmingtheiot.gda.app.GatewayDeviceApp initConfig
INFO: Attempting to load configuration: Default.
Jul 19, 2020 1:53:19 PM programmingtheiot.gda.app.GatewayDeviceApp startApp
INFO: Starting GDA...
Jul 19, 2020 1:53:19 PM programmingtheiot.gda.system.SystemPerformanceManager startManager
INFO: SystemPerformanceManager is starting...
Jul 19, 2020 1:53:19 PM programmingtheiot.gda.app.GatewayDeviceApp startApp
INFO: GDA started successfully.
Jul 19, 2020 1:53:20 PM programmingtheiot.gda.system.SystemPerformanceManager handleTelemetry
INFO: Handle telemetry results: cpuUtil=-1.0, memUtil=0.1469148
Jul 19, 2020 1:53:50 PM programmingtheiot.gda.system.SystemPerformanceManager handleTelemetry
INFO: Handle telemetry results: cpuUtil=-1.0, memUtil=0.1469148
Jul 19, 2020 1:54:20 PM programmingtheiot.gda.system.SystemPerformanceManager handleTelemetry
INFO: Handle telemetry results: cpuUtil=-1.0, memUtil=0.1469148
Jul 19, 2020 1:54:24 PM programmingtheiot.gda.app.GatewayDeviceApp stopApp
INFO: Stopping GDA...
Jul 19, 2020 1:54:24 PM programmingtheiot.gda.system.SystemPerformanceManager stopManager
INFO: SystemPerformanceManager is stopped.
Jul 19, 2020 1:54:24 PM programmingtheiot.gda.app.GatewayDeviceApp stopApp
INFO: GDA stopped successfully with exit code 0.

[labbenchstudios]

Fixed var names in example code.