node_exporter/collector/filefd_linux.go
Ben Kochie dfa53f835a
Use Go 1.13 error features
* Use `errors.Is()` for unwrapping errors.
* Use `%w` error verb in internal error formatting.

Signed-off-by: Ben Kochie <superq@gmail.com>
2020-06-16 14:47:03 +02:00

92 lines
2.4 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 !nofilefd
package collector
import (
"bytes"
"fmt"
"io/ioutil"
"os"
"strconv"
"github.com/go-kit/kit/log"
"github.com/prometheus/client_golang/prometheus"
)
const (
fileFDStatSubsystem = "filefd"
)
type fileFDStatCollector struct {
logger log.Logger
}
func init() {
registerCollector(fileFDStatSubsystem, defaultEnabled, NewFileFDStatCollector)
}
// NewFileFDStatCollector returns a new Collector exposing file-nr stats.
func NewFileFDStatCollector(logger log.Logger) (Collector, error) {
return &fileFDStatCollector{logger}, nil
}
func (c *fileFDStatCollector) Update(ch chan<- prometheus.Metric) error {
fileFDStat, err := parseFileFDStats(procFilePath("sys/fs/file-nr"))
if err != nil {
return fmt.Errorf("couldn't get file-nr: %w", err)
}
for name, value := range fileFDStat {
v, err := strconv.ParseFloat(value, 64)
if err != nil {
return fmt.Errorf("invalid value %s in file-nr: %w", value, err)
}
ch <- prometheus.MustNewConstMetric(
prometheus.NewDesc(
prometheus.BuildFQName(namespace, fileFDStatSubsystem, name),
fmt.Sprintf("File descriptor statistics: %s.", name),
nil, nil,
),
prometheus.GaugeValue, v,
)
}
return nil
}
func parseFileFDStats(filename string) (map[string]string, error) {
file, err := os.Open(filename)
if err != nil {
return nil, err
}
defer file.Close()
content, err := ioutil.ReadAll(file)
if err != nil {
return nil, err
}
parts := bytes.Split(bytes.TrimSpace(content), []byte("\u0009"))
if len(parts) < 3 {
return nil, fmt.Errorf("unexpected number of file stats in %q", filename)
}
var fileFDStat = map[string]string{}
// The file-nr proc is only 1 line with 3 values.
fileFDStat["allocated"] = string(parts[0])
// The second value is skipped as it will always be zero in linux 2.6.
fileFDStat["maximum"] = string(parts[2])
return fileFDStat, nil
}