fix when converting CPUTimes to JSON, sometimes idel have exponent

cpu/cpu.go

@@ -3,6 +3,8 @@ package cpu
 import (
 	"encoding/json"
 	"runtime"
+	"strconv"
+	"strings"
 	"time"
 )
 
@@ -95,8 +97,22 @@ func CPUPercent(interval time.Duration, percpu bool) ([]float64, error) {
 }
 
 func (c CPUTimesStat) String() string {
-	s, _ := json.Marshal(c)
-	return string(s)
+	v := []string{
+		`"cpu":"` + c.CPU + `"`,
+		`"user":` + strconv.FormatFloat(c.User, 'f', 1, 64),
+		`"system":` + strconv.FormatFloat(c.System, 'f', 1, 64),
+		`"idle":` + strconv.FormatFloat(c.Idle, 'f', 1, 64),
+		`"nice":` + strconv.FormatFloat(c.Nice, 'f', 1, 64),
+		`"iowait":` + strconv.FormatFloat(c.Iowait, 'f', 1, 64),
+		`"irq":` + strconv.FormatFloat(c.Irq, 'f', 1, 64),
+		`"softirq":` + strconv.FormatFloat(c.Softirq, 'f', 1, 64),
+		`"steal":` + strconv.FormatFloat(c.Steal, 'f', 1, 64),
+		`"guest":` + strconv.FormatFloat(c.Guest, 'f', 1, 64),
+		`"guest_nice":` + strconv.FormatFloat(c.GuestNice, 'f', 1, 64),
+		`"stolen":` + strconv.FormatFloat(c.Stolen, 'f', 1, 64),
+	}
+
+	return `{` + strings.Join(v, ",") + `}`
 }
 
 func (c CPUInfoStat) String() string {

cpu/cpu_test.go

@@ -40,7 +40,7 @@ func TestCPUTimeStat_String(t *testing.T) {
 		System: 200.1,
 		Idle:   300.1,
 	}
-	e := `{"cpu":"cpu0","user":100.1,"system":200.1,"idle":300.1,"nice":0,"iowait":0,"irq":0,"softirq":0,"steal":0,"guest":0,"guest_nice":0,"stolen":0}`
+	e := `{"cpu":"cpu0","user":100.1,"system":200.1,"idle":300.1,"nice":0.0,"iowait":0.0,"irq":0.0,"softirq":0.0,"steal":0.0,"guest":0.0,"guest_nice":0.0,"stolen":0.0}`
 	if e != fmt.Sprintf("%v", v) {
 		t.Errorf("CPUTimesStat string is invalid: %v", v)
 	}