node_exporter/collector/ntp.go

71 lines
2.0 KiB
Go

// Copyright 2015 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// +build !nontp
package collector
import (
"flag"
"fmt"
"time"
"github.com/beevik/ntp"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/log"
)
var (
ntpServer = flag.String("collector.ntp.server", "", "NTP server to use for ntp collector.")
ntpProtocolVersion = flag.Int("collector.ntp.protocol-version", 4, "NTP protocol version")
)
type ntpCollector struct {
drift prometheus.Gauge
}
func init() {
Factories["ntp"] = NewNtpCollector
}
// Takes a prometheus registry and returns a new Collector exposing
// the offset between ntp and the current system time.
func NewNtpCollector() (Collector, error) {
if *ntpServer == "" {
return nil, fmt.Errorf("no NTP server specifies, see --ntpServer")
}
if *ntpProtocolVersion < 2 || *ntpProtocolVersion > 4 {
return nil, fmt.Errorf("invalid NTP protocol version %d; must be 2, 3, or 4", *ntpProtocolVersion)
}
return &ntpCollector{
drift: prometheus.NewGauge(prometheus.GaugeOpts{
Namespace: Namespace,
Name: "ntp_drift_seconds",
Help: "Time between system time and ntp time.",
}),
}, nil
}
func (c *ntpCollector) Update(ch chan<- prometheus.Metric) (err error) {
t, err := ntp.TimeV(*ntpServer, byte(*ntpProtocolVersion))
if err != nil {
return fmt.Errorf("couldn't get NTP drift: %s", err)
}
drift := t.Sub(time.Now())
log.Debugf("Set ntp_drift_seconds: %f", drift.Seconds())
c.drift.Set(drift.Seconds())
c.drift.Collect(ch)
return err
}