categraf/inputs/ntp/ntp.go

65 lines
1.3 KiB
Go

package ntp
import (
"errors"
"log"
"time"
"flashcat.cloud/categraf/config"
"flashcat.cloud/categraf/inputs"
"github.com/toolkits/pkg/container/list"
"github.com/toolkits/pkg/nux"
)
const inputName = "ntp"
type NTPStat struct {
config.Interval
NTPServers []string `toml:"ntp_servers"`
server string
}
func init() {
inputs.Add(inputName, func() inputs.Input {
return &NTPStat{}
})
}
func (n *NTPStat) Prefix() string {
return inputName
}
func (n *NTPStat) Drop() {}
func (n *NTPStat) Init() error {
if len(n.NTPServers) == 0 {
return errors.New("ntp servers empty")
}
return nil
}
func (n *NTPStat) Gather(slist *list.SafeList) {
for _, server := range n.NTPServers {
if n.server == "" {
n.server = server
}
orgTime := time.Now()
serverReciveTime, serverTransmitTime, err := nux.NtpTwoTime(n.server)
if err != nil {
log.Println("E! failed to connect ntp server:", n.server, "error:", err)
n.server = ""
continue
}
dstTime := time.Now()
// https://en.wikipedia.org/wiki/Network_Time_Protocol
duration := ((serverReciveTime.UnixNano() - orgTime.UnixNano()) + (serverTransmitTime.UnixNano() - dstTime.UnixNano())) / 2
delta := duration / 1e6 // convert to ms
slist.PushFront(inputs.NewSample("offset_ms", delta))
break
}
}