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moby--moby/daemon/stats/collector_unix.go
Tonis Tiigi cf104d85c3 stats: avoid cgo in collector
Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>
2019-06-05 22:21:11 -07:00

75 lines
1.8 KiB
Go

// +build !windows
package stats // import "github.com/docker/docker/daemon/stats"
import (
"fmt"
"os"
"strconv"
"strings"
"github.com/opencontainers/runc/libcontainer/system"
"golang.org/x/sys/unix"
)
// platformNewStatsCollector performs platform specific initialisation of the
// Collector structure.
func platformNewStatsCollector(s *Collector) {
s.clockTicksPerSecond = uint64(system.GetClockTicks())
}
const nanoSecondsPerSecond = 1e9
// getSystemCPUUsage returns the host system's cpu usage in
// nanoseconds. An error is returned if the format of the underlying
// file does not match.
//
// Uses /proc/stat defined by POSIX. Looks for the cpu
// statistics line and then sums up the first seven fields
// provided. See `man 5 proc` for details on specific field
// information.
func (s *Collector) getSystemCPUUsage() (uint64, error) {
f, err := os.Open("/proc/stat")
if err != nil {
return 0, err
}
defer func() {
s.bufReader.Reset(nil)
f.Close()
}()
s.bufReader.Reset(f)
for {
line, err := s.bufReader.ReadString('\n')
if err != nil {
break
}
parts := strings.Fields(line)
switch parts[0] {
case "cpu":
if len(parts) < 8 {
return 0, fmt.Errorf("invalid number of cpu fields")
}
var totalClockTicks uint64
for _, i := range parts[1:8] {
v, err := strconv.ParseUint(i, 10, 64)
if err != nil {
return 0, fmt.Errorf("Unable to convert value %s to int: %s", i, err)
}
totalClockTicks += v
}
return (totalClockTicks * nanoSecondsPerSecond) /
s.clockTicksPerSecond, nil
}
}
return 0, fmt.Errorf("invalid stat format. Error trying to parse the '/proc/stat' file")
}
func (s *Collector) getNumberOnlineCPUs() (uint32, error) {
var cpuset unix.CPUSet
err := unix.SchedGetaffinity(0, &cpuset)
if err != nil {
return 0, err
}
return uint32(cpuset.Count()), nil
}