telegraf/plugins/inputs/chrony/chrony.go

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// +build linux
package chrony
import (
"errors"
"fmt"
"os/exec"
"strconv"
"strings"
"time"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/internal"
"github.com/influxdata/telegraf/plugins/inputs"
)
var (
execCommand = exec.Command // execCommand is used to mock commands in tests.
)
type Chrony struct {
DNSLookup bool `toml:"dns_lookup"`
path string
}
func (*Chrony) Description() string {
return "Get standard chrony metrics, requires chronyc executable."
}
func (*Chrony) SampleConfig() string {
return `
## If true, chronyc tries to perform a DNS lookup for the time server.
# dns_lookup = false
`
}
func (c *Chrony) Gather(acc telegraf.Accumulator) error {
if len(c.path) == 0 {
return errors.New("chronyc not found: verify that chrony is installed and that chronyc is in your PATH")
}
flags := []string{}
if !c.DNSLookup {
flags = append(flags, "-n")
}
flags = append(flags, "tracking")
cmd := execCommand(c.path, flags...)
out, err := internal.CombinedOutputTimeout(cmd, time.Second*5)
if err != nil {
return fmt.Errorf("failed to run command %s: %s - %s", strings.Join(cmd.Args, " "), err, string(out))
}
fields, tags, err := processChronycOutput(string(out))
if err != nil {
return err
}
acc.AddFields("chrony", fields, tags)
return nil
}
// processChronycOutput takes in a string output from the chronyc command, like:
//
// Reference ID : 192.168.1.22 (ntp.example.com)
// Stratum : 3
// Ref time (UTC) : Thu May 12 14:27:07 2016
// System time : 0.000020390 seconds fast of NTP time
// Last offset : +0.000012651 seconds
// RMS offset : 0.000025577 seconds
// Frequency : 16.001 ppm slow
// Residual freq : -0.000 ppm
// Skew : 0.006 ppm
// Root delay : 0.001655 seconds
// Root dispersion : 0.003307 seconds
// Update interval : 507.2 seconds
// Leap status : Normal
//
// The value on the left side of the colon is used as field name, if the first field on
// the right side is a float. If it cannot be parsed as float, it is a tag name.
//
// Ref time is ignored and all names are converted to snake case.
//
// It returns (<fields>, <tags>)
func processChronycOutput(out string) (map[string]interface{}, map[string]string, error) {
tags := map[string]string{}
fields := map[string]interface{}{}
lines := strings.Split(strings.TrimSpace(out), "\n")
for _, line := range lines {
stats := strings.Split(line, ":")
if len(stats) < 2 {
return nil, nil, fmt.Errorf("unexpected output from chronyc, expected ':' in %s", out)
}
name := strings.ToLower(strings.Replace(strings.TrimSpace(stats[0]), " ", "_", -1))
// ignore reference time
if strings.Contains(name, "ref_time") {
continue
}
valueFields := strings.Fields(stats[1])
if len(valueFields) == 0 {
return nil, nil, fmt.Errorf("unexpected output from chronyc: %s", out)
}
if strings.Contains(strings.ToLower(name), "stratum") {
tags["stratum"] = valueFields[0]
continue
}
if strings.Contains(strings.ToLower(name), "reference_id") {
tags["reference_id"] = valueFields[0]
continue
}
value, err := strconv.ParseFloat(valueFields[0], 64)
if err != nil {
tags[name] = strings.ToLower(strings.Join(valueFields, " "))
continue
}
if strings.Contains(stats[1], "slow") {
value = -value
}
fields[name] = value
}
return fields, tags, nil
}
func init() {
c := Chrony{}
path, _ := exec.LookPath("chronyc")
if len(path) > 0 {
c.path = path
}
inputs.Add("chrony", func() telegraf.Input {
return &c
})
}