使用 golang 收集系统指标

// copy code from github.com/shirou/gopsutil
package sys

import (
"bufio"
"os"
"strings"
)

// ReadLines reads contents from file and splits them by new line.
// A convenience wrapper to ReadLinesOffsetN(filename, 0, -1).
func readLines(filename string) ([]string, error) {
return readLinesOffsetN(filename, 0, -1)
}

// ReadLines reads contents from file and splits them by new line.
// The offset tells at which line number to start.
// The count determines the number of lines to read (starting from offset):
//   n >= 0: at most n lines
//   n < 0: whole file
func readLinesOffsetN(filename string, offset uint, n int) ([]string, error) {
f, err := os.Open(filename)
if err != nil {
return []string{""}, err
}
defer f.Close()

var ret []string

r := bufio.NewReader(f)
for i := 0; i < n+int(offset) || n < 0; i++ {
line, err := r.ReadString('\n')
if err != nil {
break
}
if i < int(offset) {
continue
}
ret = append(ret, strings.Trim(line, "\n"))
}

return ret, nil
}

// copy code from github.com/shirou/gopsutil
// almost the same, but change a lot, especially the returned struct
package sys

import (
"errors"
"io/ioutil"
"strconv"
"strings"
)

type SysStat struct {
// /proc/loadavg
Load1  float64
Load5  float64
Load15 float64
// /proc/meminfo
Total       uint64
Available   uint64
Used        uint64
UsedPercent float64
Free        uint64
Active      uint64
Inactive    uint64
Buffers     uint64
Cached      uint64
Wired       uint64
Shared      uint64
// /proc/net/dev
// sum of all interfaces
Name        string
BytesSent   uint64
BytesRecv   uint64
PacketsSent uint64
PacketsRecv uint64
// /proc/stat
CPU       string
User      float64
System    float64
Idle      float64
Nice      float64
Iowait    float64
Irq       float64
Softirq   float64
Steal     float64
Guest     float64
GuestNice float64
Stolen    float64
}

func GetSysStat() *SysStat {
stat := new(SysStat)
stat.cPUTimes()
stat.netIOCounters()
stat.virtualMemory()
stat.loadAvg()
return stat
}

func (stat *SysStat) cPUTimes() error {
filename := "/proc/stat"
var lines = []string{}
lines, _ = readLinesOffsetN(filename, 0, 1)

err := stat.parseStatLine(lines[0])
if err != nil {
return err
}
return nil
}

func (stat *SysStat) parseStatLine(line string) error {
fields := strings.Fields(line)

if strings.HasPrefix(fields[0], "cpu") == false {
return errors.New("not contain cpu")
}

cpu := fields[0]
if cpu == "cpu" {
cpu = "cpu-total"
}
user, err := strconv.ParseFloat(fields[1], 64)
if err != nil {
return err
}
nice, err := strconv.ParseFloat(fields[2], 64)
if err != nil {
return err
}
system, err := strconv.ParseFloat(fields[3], 64)
if err != nil {
return err
}
idle, err := strconv.ParseFloat(fields[4], 64)
if err != nil {
return err
}
iowait, err := strconv.ParseFloat(fields[5], 64)
if err != nil {
return err
}
irq, err := strconv.ParseFloat(fields[6], 64)
if err != nil {
return err
}
softirq, err := strconv.ParseFloat(fields[7], 64)
if err != nil {
return err
}
stolen, err := strconv.ParseFloat(fields[8], 64)
if err != nil {
return err
}

cpu_tick := float64(100) // TODO: how to get _SC_CLK_TCK ?

stat.CPU = cpu
stat.User = float64(user) / cpu_tick
stat.Nice = float64(nice) / cpu_tick
stat.System = float64(system) / cpu_tick
stat.Idle = float64(idle) / cpu_tick
stat.Iowait = float64(iowait) / cpu_tick
stat.Irq = float64(irq) / cpu_tick
stat.Softirq = float64(softirq) / cpu_tick
stat.Stolen = float64(stolen) / cpu_tick

if len(fields) > 9 { // Linux >= 2.6.11
steal, err := strconv.ParseFloat(fields[9], 64)
if err != nil {
return err
}
stat.Steal = float64(steal)
}
if len(fields) > 10 { // Linux >= 2.6.24
guest, err := strconv.ParseFloat(fields[10], 64)
if err != nil {
return err
}
stat.Guest = float64(guest)
}
if len(fields) > 11 { // Linux >= 3.2.0
guestNice, err := strconv.ParseFloat(fields[11], 64)
if err != nil {
return err
}
stat.GuestNice = float64(guestNice)
}

return nil
}

type netIOCountersStat struct {
Name        string
BytesSent   uint64
BytesRecv   uint64
PacketsSent uint64
PacketsRecv uint64
}

func (stat *SysStat) netIOCounters() error {
filename := "/proc/net/dev"
lines, err := readLines(filename)
if err != nil {
return err
}

statlen := len(lines) - 1

all := make([]netIOCountersStat, 0, statlen)

for _, line := range lines[2:] {
parts := strings.SplitN(line, ":", 2)
if len(parts) != 2 {
continue
}
interfaceName := strings.TrimSpace(parts[0])
if interfaceName == "" {
continue
}

fields := strings.Fields(strings.TrimSpace(parts[1]))
bytesRecv, err := strconv.ParseUint(fields[0], 10, 64)
if err != nil {
return err
}
packetsRecv, err := strconv.ParseUint(fields[1], 10, 64)
if err != nil {
return err
}
bytesSent, err := strconv.ParseUint(fields[8], 10, 64)
if err != nil {
return err
}
packetsSent, err := strconv.ParseUint(fields[9], 10, 64)
if err != nil {
return err
}

nic := netIOCountersStat{
Name:        interfaceName,
BytesRecv:   bytesRecv,
PacketsRecv: packetsRecv,
BytesSent:   bytesSent,
PacketsSent: packetsSent}

all = append(all, nic)
}

return stat.getNetIOCountersAll(all)
}

func (stat *SysStat) getNetIOCountersAll(n []netIOCountersStat) error {
stat.Name = "all-interfaces"
for _, nic := range n {
stat.BytesRecv += nic.BytesRecv
stat.PacketsRecv += nic.PacketsRecv
stat.BytesSent += nic.BytesSent
stat.PacketsSent += nic.PacketsSent
}
return nil
}

func (stat *SysStat) virtualMemory() error {
filename := "/proc/meminfo"
lines, _ := readLines(filename)

for _, line := range lines {
fields := strings.Split(line, ":")
if len(fields) != 2 {
continue
}
key := strings.TrimSpace(fields[0])
value := strings.TrimSpace(fields[1])
value = strings.Replace(value, " kB", "", -1)

t, err := strconv.ParseUint(value, 10, 64)
if err != nil {
return err
}
switch key {
case "MemTotal":
stat.Total = t * 1000
case "MemFree":
stat.Free = t * 1000
case "Buffers":
stat.Buffers = t * 1000
case "Cached":
stat.Cached = t * 1000
case "Active":
stat.Active = t * 1000
case "Inactive":
stat.Inactive = t * 1000
}
}
stat.Available = stat.Free + stat.Buffers + stat.Cached
stat.Used = stat.Total - stat.Free
stat.UsedPercent = float64(stat.Total-stat.Available) / float64(stat.Total) * 100.0

return nil
}

func (stat *SysStat) loadAvg() error {
filename := "/proc/loadavg"
line, err := ioutil.ReadFile(filename)
if err != nil {
return err
}

values := strings.Fields(string(line))

load1, err := strconv.ParseFloat(values[0], 64)
if err != nil {
return err
}
load5, err := strconv.ParseFloat(values[1], 64)
if err != nil {
return err
}
load15, err := strconv.ParseFloat(values[2], 64)
if err != nil {
return err
}

stat.Load1 = load1
stat.Load5 = load5
stat.Load15 = load15

return nil
}