Merge pull request #581 from CMGS/master

get docker container cpu usage from cpuacct.usage

cpu/cpu_linux.go

@@ -13,7 +13,7 @@ import (
 	"github.com/shirou/gopsutil/internal/common"
 )
 
-var cpu_tick = float64(100)
+var CPUTick = float64(100)
 
 func init() {
 	getconf, err := exec.LookPath("/usr/bin/getconf")
@@ -25,7 +25,7 @@ func init() {
 	if err == nil {
 		i, err := strconv.ParseFloat(strings.TrimSpace(string(out)), 64)
 		if err == nil {
-			cpu_tick = float64(i)
+			CPUTick = i
 		}
 	}
 }
@@ -250,34 +250,34 @@ func parseStatLine(line string) (*TimesStat, error) {
 
 	ct := &TimesStat{
 		CPU:     cpu,
-		User:    float64(user) / cpu_tick,
-		Nice:    float64(nice) / cpu_tick,
-		System:  float64(system) / cpu_tick,
-		Idle:    float64(idle) / cpu_tick,
-		Iowait:  float64(iowait) / cpu_tick,
-		Irq:     float64(irq) / cpu_tick,
-		Softirq: float64(softirq) / cpu_tick,
+		User:    user / CPUTick,
+		Nice:    nice / CPUTick,
+		System:  system / CPUTick,
+		Idle:    idle / CPUTick,
+		Iowait:  iowait / CPUTick,
+		Irq:     irq / CPUTick,
+		Softirq: softirq / CPUTick,
 	}
 	if len(fields) > 8 { // Linux >= 2.6.11
 		steal, err := strconv.ParseFloat(fields[8], 64)
 		if err != nil {
 			return nil, err
 		}
-		ct.Steal = float64(steal) / cpu_tick
+		ct.Steal = steal / CPUTick
 	}
 	if len(fields) > 9 { // Linux >= 2.6.24
 		guest, err := strconv.ParseFloat(fields[9], 64)
 		if err != nil {
 			return nil, err
 		}
-		ct.Guest = float64(guest) / cpu_tick
+		ct.Guest = guest / CPUTick
 	}
 	if len(fields) > 10 { // Linux >= 3.2.0
 		guestNice, err := strconv.ParseFloat(fields[10], 64)
 		if err != nil {
 			return nil, err
 		}
-		ct.GuestNice = float64(guestNice) / cpu_tick
+		ct.GuestNice = guestNice / CPUTick
 	}
 
 	return ct, nil

docker/docker.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 
+	"github.com/shirou/gopsutil/cpu"
 	"github.com/shirou/gopsutil/internal/common"
 )
 
@@ -12,6 +13,13 @@ var ErrCgroupNotAvailable = errors.New("cgroup not available")
 
 var invoke common.Invoker = common.Invoke{}
 
+const nanoseconds = 1e9
+
+type CgroupCPUStat struct {
+	cpu.TimesStat
+	Usage float64
+}
+
 type CgroupMemStat struct {
 	ContainerID             string `json:"containerID"`
 	Cache                   uint64 `json:"cache"`

docker/docker_linux.go

@@ -93,6 +93,14 @@ func CgroupCPU(containerID string, base string) (*cpu.TimesStat, error) {
 	return CgroupCPUWithContext(context.Background(), containerID, base)
 }
 
+// CgroupCPUUsage returnes specified cgroup id CPU usage.
+// containerID is same as docker id if you use docker.
+// If you use container via systemd.slice, you could use
+// containerID = docker-<container id>.scope and base=/sys/fs/cgroup/cpuacct/system.slice/
+func CgroupCPUUsage(containerID string, base string) (float64, error) {
+	return CgroupCPUUsageWithContext(context.Background(), containerID, base)
+}
+
 func CgroupCPUWithContext(ctx context.Context, containerID string, base string) (*cpu.TimesStat, error) {
 	statfile := getCgroupFilePath(containerID, base, "cpuacct", "cpuacct.stat")
 	lines, err := common.ReadLines(statfile)
@@ -109,20 +117,34 @@ func CgroupCPUWithContext(ctx context.Context, containerID string, base string)
 		if fields[0] == "user" {
 			user, err := strconv.ParseFloat(fields[1], 64)
 			if err == nil {
-				ret.User = float64(user)
+				ret.User = user / cpu.CPUTick
 			}
 		}
 		if fields[0] == "system" {
 			system, err := strconv.ParseFloat(fields[1], 64)
 			if err == nil {
-				ret.System = float64(system)
+				ret.System = system / cpu.CPUTick
 			}
 		}
 	}
-
 	return ret, nil
 }
 
+func CgroupCPUUsageWithContext(ctx context.Context, containerID, base string) (float64, error) {
+	usagefile := getCgroupFilePath(containerID, base, "cpuacct", "cpuacct.usage")
+	lines, err := common.ReadLinesOffsetN(usagefile, 0, 1)
+	if err != nil {
+		return 0.0, err
+	}
+
+	ns, err := strconv.ParseFloat(lines[0], 64)
+	if err != nil {
+		return 0.0, err
+	}
+
+	return ns / nanoseconds, nil
+}
+
 func CgroupCPUDocker(containerid string) (*cpu.TimesStat, error) {
 	return CgroupCPUDockerWithContext(context.Background(), containerid)
 }
@@ -131,6 +153,10 @@ func CgroupCPUDockerWithContext(ctx context.Context, containerid string) (*cpu.T
 	return CgroupCPU(containerid, common.HostSys("fs/cgroup/cpuacct/docker"))
 }
 
+func CgroupCPUDockerUsageWithContext(ctx context.Context, containerid string) (float64, error) {
+	return CgroupCPUUsage(containerid, common.HostSys("fs/cgroup/cpuacct/docker"))
+}
+
 func CgroupMem(containerID string, base string) (*CgroupMemStat, error) {
 	return CgroupMemWithContext(context.Background(), containerID, base)
 }

docker/docker_notlinux.go

@@ -4,7 +4,8 @@ package docker
 
 import (
 	"context"
-	"github.com/shirou/gopsutil/cpu"
+
+	cpu "github.com/shirou/gopsutil/cpu"
 	"github.com/shirou/gopsutil/internal/common"
 )