✨ Update CPU metrics calculation method and add test

The CPU metrics calculation method in cpu.go has been updated with a more accurate method, which involves getting CPU times at the start, waiting for a short interval, then getting CPU times again and calculating the difference. An additional function, totalCPUTime, has been implemented to facilitate this. A new test case for CPU usage calculation has also been added in cpu_test.go.

cpu.go

@@ -1,27 +1,64 @@
 package oneuptime_InfrastructureAgent_go
 
 import (
+	"fmt"
 	"github.com/gookit/slog"
 	"github.com/shirou/gopsutil/v3/cpu"
-	"github.com/shirou/gopsutil/v3/load"
+	"time"
 )
 
 func getCpuMetrics() *CPUMetrics {
-	avg, err := load.Avg()
+	//avg, err := load.Avg()
+	//if err != nil {
+	//	slog.Error(err)
+	//	return nil
+	//}
+	//
+	//numCpu, err := cpu.Counts(true)
+	//if err != nil {
+	//	slog.Error(err)
+	//	return nil
+	//}
+	//
+	//// Calculate CPU usage, which is the average load over the last minute divided by the number of CPUs
+	//cpuUsage := (avg.Load1 / float64(numCpu)) * 100
+
+	//trying new calculation method, more accurate
+	// Get CPU times at the start
+	startTimes, err := cpu.Times(false) // false to get the aggregate of all CPUs
 	if err != nil {
-		slog.Error(err)
+		slog.Error(fmt.Errorf("error fetching initial CPU times: %v", err))
 		return nil
 	}
 
-	numCpu, err := cpu.Counts(true)
+	// Wait for a short interval (e.g., 1000 milliseconds)
+	time.Sleep(1000 * time.Millisecond)
+
+	// Get CPU times after the interval
+	endTimes, err := cpu.Times(false)
 	if err != nil {
-		slog.Error(err)
+		slog.Error(fmt.Errorf("error fetching final CPU times: %v", err))
+		return nil
+	}
+
+	// Calculate the difference in total and idle times
+	totalDelta := totalCPUTime(endTimes[0]) - totalCPUTime(startTimes[0])
+	idleDelta := endTimes[0].Idle - startTimes[0].Idle
+
+	// Calculate the CPU usage percentage
+	if totalDelta == 0 {
+		slog.Error("totalDelta is 0")
 		return nil
 	}
+	cpuUsagePercent := (1 - idleDelta/totalDelta) * 100
 
-	// Calculate CPU usage, which is the average load over the last minute divided by the number of CPUs
-	cpuUsage := (avg.Load1 / float64(numCpu)) * 100
 	return &CPUMetrics{
-		PercentUsed: cpuUsage,
+		PercentUsed: cpuUsagePercent,
 	}
 }
+
+func totalCPUTime(times cpu.TimesStat) float64 {
+	return times.User + times.System + times.Idle + times.Nice +
+		times.Iowait + times.Irq + times.Softirq + times.Steal +
+		times.Guest + times.GuestNice
+}

cpu_test.go

@@ -0,0 +1,7 @@
+package oneuptime_InfrastructureAgent_go
+
+import "testing"
+
+func TestCpu(t *testing.T) {
+	t.Log("Usage (%): ", getCpuMetrics().PercentUsed)
+}