node_exporter/collector/loadavg_linux.go

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2015-09-26 15:36:40 +00:00
// 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 !noloadavg
package collector
import (
"fmt"
"io/ioutil"
"strconv"
"strings"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/log"
)
type loadavgCollector struct {
metric []prometheus.Gauge
}
func init() {
Factories["loadavg"] = NewLoadavgCollector
}
// Take a prometheus registry and return a new Collector exposing load average.
func NewLoadavgCollector() (Collector, error) {
return &loadavgCollector{
metric: []prometheus.Gauge{
prometheus.NewGauge(prometheus.GaugeOpts{
Namespace: Namespace,
Name: "load1",
Help: "1m load average.",
}),
prometheus.NewGauge(prometheus.GaugeOpts{
Namespace: Namespace,
Name: "load5",
Help: "5m load average.",
}),
prometheus.NewGauge(prometheus.GaugeOpts{
Namespace: Namespace,
Name: "load15",
Help: "15m load average.",
}),
},
}, nil
}
func (c *loadavgCollector) Update(ch chan<- prometheus.Metric) (err error) {
loads, err := getLoad()
if err != nil {
return fmt.Errorf("couldn't get load: %s", err)
}
for i, load := range loads {
log.Debugf("Set load %d: %f", i, load)
c.metric[i].Set(load)
c.metric[i].Collect(ch)
}
return err
}
// Read loadavg from /proc.
func getLoad() (loads []float64, err error) {
data, err := ioutil.ReadFile(procFilePath("loadavg"))
if err != nil {
return nil, err
}
loads, err = parseLoad(string(data))
if err != nil {
return nil, err
}
return loads, nil
}
// Parse /proc loadavg and return 1m, 5m and 15m.
func parseLoad(data string) (loads []float64, err error) {
loads = make([]float64, 3)
parts := strings.Fields(data)
if len(parts) >= 3 {
for i, load := range parts[0:3] {
loads[i], err = strconv.ParseFloat(load, 64)
if err != nil {
return nil, fmt.Errorf("could not parse load '%s': %s", load, err)
}
}
} else {
return nil, fmt.Errorf("unexpected content in %s", procFilePath("loadavg"))
}
return loads, nil
}