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|
package main
import (
"context"
"fmt"
"os/exec"
"strconv"
"strings"
"time"
)
// Tracking mirrors `chronyc -c tracking`.
type Tracking struct {
RefID string `json:"refId"`
RefName string `json:"refName"`
Stratum int `json:"stratum"`
RefTime float64 `json:"refTime"`
SystemOffset float64 `json:"systemOffset"` // seconds; positive = system clock slow of NTP time
LastOffset float64 `json:"lastOffset"`
RMSOffset float64 `json:"rmsOffset"`
FreqPPM float64 `json:"freqPpm"` // positive = clock runs slow
ResidFreqPPM float64 `json:"residFreqPpm"`
SkewPPM float64 `json:"skewPpm"`
RootDelay float64 `json:"rootDelay"`
RootDispersion float64 `json:"rootDispersion"`
UpdateInterval float64 `json:"updateInterval"`
Leap string `json:"leap"`
}
// Source merges a `chronyc -c sources` row with its `sourcestats` row.
type Source struct {
Mode string `json:"mode"` // ^ server, = peer, # refclock
State string `json:"state"` // * + - x ~ ?
Name string `json:"name"`
Stratum int `json:"stratum"`
Poll int `json:"poll"`
Reach int `json:"reach"`
LastRx int64 `json:"lastRx"` // seconds ago, -1 if never
Offset float64 `json:"offset"` // adjusted offset of last sample
RawOffset float64 `json:"rawOffset"`
Error float64 `json:"error"`
NP int `json:"np,omitempty"`
NR int `json:"nr,omitempty"`
Span int `json:"span,omitempty"`
Freq *float64 `json:"freqPpm,omitempty"`
Skew *float64 `json:"skewPpm,omitempty"`
StdDev *float64 `json:"stdDev,omitempty"`
}
// ServerStats is the subset of `chronyc -c serverstats` we show. Requires
// access to chronyd's privileged command socket.
type ServerStats struct {
NTPReceived uint64 `json:"ntpReceived"`
NTPDropped uint64 `json:"ntpDropped"`
RatePerSec float64 `json:"ratePerSec"`
}
type ChronySnap struct {
Tracking *Tracking `json:"tracking,omitempty"`
Sources []Source `json:"sources"`
Server *ServerStats `json:"server,omitempty"`
Error string `json:"error,omitempty"`
}
type chronyClient struct {
path string
serverStatsDenied bool
lastServerRx uint64
lastServerAt time.Time
}
func (c *chronyClient) run(ctx context.Context, cmd string) ([][]string, error) {
ctx, cancel := context.WithTimeout(ctx, 2*time.Second)
defer cancel()
out, err := exec.CommandContext(ctx, c.path, "-c", "-n", cmd).Output()
if err != nil {
msg := strings.TrimSpace(string(out))
if ee, ok := err.(*exec.ExitError); ok && len(ee.Stderr) > 0 {
msg = strings.TrimSpace(string(ee.Stderr))
}
if msg == "" {
msg = err.Error()
}
return nil, fmt.Errorf("chronyc %s: %s", cmd, msg)
}
var rows [][]string
for _, line := range strings.Split(strings.TrimSpace(string(out)), "\n") {
if line = strings.TrimSpace(line); line != "" {
rows = append(rows, strings.Split(line, ","))
}
}
return rows, nil
}
func f64(s string) float64 { v, _ := strconv.ParseFloat(s, 64); return v }
func atoi(s string) int { v, _ := strconv.Atoi(s); return v }
func (c *chronyClient) Poll(ctx context.Context) ChronySnap {
snap := ChronySnap{Sources: []Source{}}
var errs []string
if rows, err := c.run(ctx, "tracking"); err != nil {
errs = append(errs, err.Error())
} else if len(rows) > 0 && len(rows[0]) >= 14 {
r := rows[0]
snap.Tracking = &Tracking{
RefID: r[0], RefName: r[1], Stratum: atoi(r[2]), RefTime: f64(r[3]),
SystemOffset: f64(r[4]), LastOffset: f64(r[5]), RMSOffset: f64(r[6]),
FreqPPM: f64(r[7]), ResidFreqPPM: f64(r[8]), SkewPPM: f64(r[9]),
RootDelay: f64(r[10]), RootDispersion: f64(r[11]),
UpdateInterval: f64(r[12]), Leap: r[13],
}
}
if rows, err := c.run(ctx, "sources"); err != nil {
errs = append(errs, err.Error())
} else {
for _, r := range rows {
if len(r) < 10 {
continue
}
reach, _ := strconv.ParseInt(r[5], 8, 32)
lastRx, perr := strconv.ParseInt(r[6], 10, 64)
if perr != nil {
lastRx = -1
}
snap.Sources = append(snap.Sources, Source{
Mode: r[0], State: r[1], Name: r[2], Stratum: atoi(r[3]), Poll: atoi(r[4]),
Reach: int(reach), LastRx: lastRx, Offset: f64(r[7]), RawOffset: f64(r[8]), Error: f64(r[9]),
})
}
}
if rows, err := c.run(ctx, "sourcestats"); err != nil {
errs = append(errs, err.Error())
} else {
byName := map[string]*Source{}
for i := range snap.Sources {
byName[snap.Sources[i].Name] = &snap.Sources[i]
}
for _, r := range rows {
if len(r) < 8 {
continue
}
if s := byName[r[0]]; s != nil {
fr, sk, sd := f64(r[4]), f64(r[5]), f64(r[7])
s.NP, s.NR, s.Span = atoi(r[1]), atoi(r[2]), atoi(r[3])
s.Freq, s.Skew, s.StdDev = &fr, &sk, &sd
}
}
}
if !c.serverStatsDenied {
if rows, err := c.run(ctx, "serverstats"); err != nil {
if strings.Contains(err.Error(), "Not authorised") {
c.serverStatsDenied = true // don't keep spawning a doomed command
}
} else if len(rows) > 0 && len(rows[0]) >= 2 {
rx, _ := strconv.ParseUint(rows[0][0], 10, 64)
dr, _ := strconv.ParseUint(rows[0][1], 10, 64)
ss := &ServerStats{NTPReceived: rx, NTPDropped: dr}
now := time.Now()
if !c.lastServerAt.IsZero() && rx >= c.lastServerRx {
ss.RatePerSec = float64(rx-c.lastServerRx) / now.Sub(c.lastServerAt).Seconds()
}
c.lastServerRx, c.lastServerAt = rx, now
snap.Server = ss
}
}
snap.Error = strings.Join(errs, "; ")
return snap
}
|
