Unix load average

cpu.go

@@ -1,6 +1,7 @@
 package systats
 
 import (
+	"errors"
 	"regexp"
 	"strconv"
 	"strings"
@@ -12,13 +13,16 @@ import (
 
 // CPU holds information on CPU and CPU usage
 type CPU struct {
-	LoadAvg   int    `json:"loadAvg"`
-	CoreAvg   []int  `json:"coreAvg"`
-	Model     string `json:"model"`
-	NoOfCores int    `json:"noOfCores"`
-	Freq      string `json:"freq"`
-	Cache     string `json:"cache"`
-	Time      int64  `json:"time"`
+	LoadAvg   int     `json:"loadAvg"`
+	CoreAvg   []int   `json:"coreAvg"`
+	Load1     float64 `json:"load1"`
+	Load5     float64 `json:"load5"`
+	Load15    float64 `json:"load15"`
+	Model     string  `json:"model"`
+	NoOfCores int     `json:"noOfCores"`
+	Freq      string  `json:"freq"`
+	Cache     string  `json:"cache"`
+	Time      int64   `json:"time"`
 }
 
 func getCPU(systats *SyStats, milliseconds int) (CPU, error) {
@@ -43,9 +47,31 @@ func getCPU(systats *SyStats, milliseconds int) (CPU, error) {
 
 	processCPUInfoFileContent(&output, &cpuinfoStr)
 
+	loadAvgStr, err := fileops.ReadFileWithError(systats.LoadAvgPath)
+	if err != nil {
+		return output, err
+	}
+	if err := processLoadAvgFileContent(&output, &loadAvgStr); err != nil {
+		return output, err
+	}
+
 	return output, nil
 }
 
+// processLoadAvgFileContent parses /proc/loadavg's 1/5/15-minute load
+// averages - the traditional Unix "load average" (uptime/top/w), distinct
+// from LoadAvg/CoreAvg above which are CPU utilization percentages.
+func processLoadAvgFileContent(output *CPU, content *string) error {
+	fields := strings.Fields(*content)
+	if len(fields) < 3 {
+		return errors.New("unexpected loadavg format")
+	}
+	output.Load1 = strops.ToFloat64(fields[0])
+	output.Load5 = strops.ToFloat64(fields[1])
+	output.Load15 = strops.ToFloat64(fields[2])
+	return nil
+}
+
 func processCPUInfoFileContent(output *CPU, content *string) {
 	split := strings.Split(*content, "\n")
 

systats.go

@@ -30,6 +30,7 @@ type SyStats struct {
 	EtcPath         string
 	UptimePath      string
 	MountsPath      string
+	LoadAvgPath     string
 	// ProcessCPUMode selects how GetTopProcesses computes CPU usage:
 	// CPUUsageInstant (default, used when left empty) or CPUUsageAverage.
 	ProcessCPUMode string
@@ -44,6 +45,7 @@ func New() SyStats {
 		EtcPath:         "/etc/",
 		UptimePath:      "/proc/uptime",
 		MountsPath:      "/proc/mounts",
+		LoadAvgPath:     "/proc/loadavg",
 		ProcessCPUMode:  CPUUsageInstant,
 	}
 }

systats_test.go

@@ -145,6 +145,7 @@ func TestGetCPU(t *testing.T) {
 	syStats := systats.SyStats{
 		CPUinfoFilePath: "./test_files/cpuinfo.txt",
 		StatFilePath:    "/proc/stat",
+		LoadAvgPath:     "./test_files/loadavg.txt",
 	}
 	cpu, err := syStats.GetCPU()
 	if err != nil {
@@ -160,6 +161,21 @@ func TestGetCPU(t *testing.T) {
 		t.Errorf("Got invalid value. got: %d, want: %d", cpu.NoOfCores, 4)
 		return
 	}
+
+	if cpu.Load1 != 0.52 {
+		t.Errorf("Got invalid value. got: %f, want: %f", cpu.Load1, 0.52)
+		return
+	}
+
+	if cpu.Load5 != 0.58 {
+		t.Errorf("Got invalid value. got: %f, want: %f", cpu.Load5, 0.58)
+		return
+	}
+
+	if cpu.Load15 != 0.59 {
+		t.Errorf("Got invalid value. got: %f, want: %f", cpu.Load15, 0.59)
+		return
+	}
 }
 
 func TestGetSystem(t *testing.T) {

test_files/loadavg.txt

@@ -0,0 +1 @@
+0.52 0.58 0.59 2/391 12345