Add system uptime metric, string formatted AND in float64

closes #150

plugins/system/ps.go

@@ -10,7 +10,6 @@ import (
 	"github.com/influxdb/telegraf/plugins/system/ps/cpu"
 	"github.com/influxdb/telegraf/plugins/system/ps/disk"
 	"github.com/influxdb/telegraf/plugins/system/ps/docker"
-	"github.com/influxdb/telegraf/plugins/system/ps/load"
 	"github.com/influxdb/telegraf/plugins/system/ps/mem"
 	"github.com/influxdb/telegraf/plugins/system/ps/net"
 )
@@ -24,7 +23,6 @@ type DockerContainerStat struct {
 }
 
 type PS interface {
-	LoadAvg() (*load.LoadAvgStat, error)
 	CPUTimes(perCPU, totalCPU bool) ([]cpu.CPUTimesStat, error)
 	DiskUsage() ([]*disk.DiskUsageStat, error)
 	NetIO() ([]net.NetIOCountersStat, error)
@@ -45,10 +43,6 @@ type systemPS struct {
 	dockerClient *dc.Client
 }
 
-func (s *systemPS) LoadAvg() (*load.LoadAvgStat, error) {
-	return load.LoadAvg()
-}
-
 func (s *systemPS) CPUTimes(perCPU, totalCPU bool) ([]cpu.CPUTimesStat, error) {
 	var cpuTimes []cpu.CPUTimesStat
 	if perCPU {

plugins/system/system.go

@@ -1,39 +1,48 @@
 package system
 
-import "github.com/influxdb/telegraf/plugins"
+import (
+	"github.com/cloudfoundry/gosigar"
 
-type SystemStats struct {
-	ps PS
-}
+	"github.com/influxdb/telegraf/plugins"
+)
+
+type SystemStats struct{}
 
 func (_ *SystemStats) Description() string {
-	return "Read metrics about system load"
+	return "Read metrics about system load & uptime"
 }
 
 func (_ *SystemStats) SampleConfig() string { return "" }
 
-func (s *SystemStats) add(acc plugins.Accumulator,
+func (_ *SystemStats) add(acc plugins.Accumulator,
 	name string, val float64, tags map[string]string) {
 	if val >= 0 {
 		acc.Add(name, val, tags)
 	}
 }
 
-func (s *SystemStats) Gather(acc plugins.Accumulator) error {
-	lv, err := s.ps.LoadAvg()
-	if err != nil {
+func (_ *SystemStats) Gather(acc plugins.Accumulator) error {
+	loadavg := sigar.LoadAverage{}
+	if err := loadavg.Get(); err != nil {
 		return err
 	}
 
-	acc.Add("load1", lv.Load1, nil)
-	acc.Add("load5", lv.Load5, nil)
-	acc.Add("load15", lv.Load15, nil)
+	uptime := sigar.Uptime{}
+	if err := uptime.Get(); err != nil {
+		return err
+	}
+
+	acc.Add("load1", loadavg.One, nil)
+	acc.Add("load5", loadavg.Five, nil)
+	acc.Add("load15", loadavg.Fifteen, nil)
+	acc.Add("uptime", uptime.Length, nil)
+	acc.Add("uptime_format", uptime.Format(), nil)
 
 	return nil
 }
 
 func init() {
 	plugins.Add("system", func() plugins.Plugin {
-		return &SystemStats{ps: &systemPS{}}
+		return &SystemStats{}
 	})
 }

plugins/system/system_test.go

@@ -7,7 +7,6 @@ import (
 
 	"github.com/influxdb/telegraf/plugins/system/ps/cpu"
 	"github.com/influxdb/telegraf/plugins/system/ps/disk"
-	"github.com/influxdb/telegraf/plugins/system/ps/load"
 	"github.com/influxdb/telegraf/plugins/system/ps/mem"
 	"github.com/influxdb/telegraf/plugins/system/ps/net"
 	"github.com/influxdb/telegraf/testutil"
@@ -22,14 +21,6 @@ func TestSystemStats_GenerateStats(t *testing.T) {
 
 	var acc testutil.Accumulator
 
-	lv := &load.LoadAvgStat{
-		Load1:  0.3,
-		Load5:  1.5,
-		Load15: 0.8,
-	}
-
-	mps.On("LoadAvg").Return(lv, nil)
-
 	cts := cpu.CPUTimesStat{
 		CPU:       "cpu0",
 		User:      3.1,
@@ -128,15 +119,6 @@ func TestSystemStats_GenerateStats(t *testing.T) {
 
 	mps.On("SwapStat").Return(sms, nil)
 
-	ss := &SystemStats{ps: &mps}
-
-	err := ss.Gather(&acc)
-	require.NoError(t, err)
-
-	assert.True(t, acc.CheckValue("load1", 0.3))
-	assert.True(t, acc.CheckValue("load5", 1.5))
-	assert.True(t, acc.CheckValue("load15", 0.8))
-
 	cs := NewCPUStats(&mps)
 
 	cputags := map[string]string{
@@ -144,7 +126,7 @@ func TestSystemStats_GenerateStats(t *testing.T) {
 	}
 
 	preCPUPoints := len(acc.Points)
-	err = cs.Gather(&acc)
+	err := cs.Gather(&acc)
 	require.NoError(t, err)
 	numCPUPoints := len(acc.Points) - preCPUPoints