node_exporter/collector/netstat_linux.go

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// 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 !nonetstat
package collector
import (
"bufio"
"errors"
"fmt"
"io"
"os"
"regexp"
"strconv"
"strings"
"github.com/go-kit/log"
"github.com/prometheus/client_golang/prometheus"
"gopkg.in/alecthomas/kingpin.v2"
)
const (
netStatsSubsystem = "netstat"
)
var (
netStatFields = kingpin.Flag("collector.netstat.fields", "Regexp of fields to return for netstat collector.").Default("^(.*_(InErrors|InErrs)|Ip_Forwarding|Ip(6|Ext)_(InOctets|OutOctets)|Icmp6?_(InMsgs|OutMsgs)|TcpExt_(Listen.*|Syncookies.*|TCPSynRetrans)|Tcp_(ActiveOpens|InSegs|OutSegs|OutRsts|PassiveOpens|RetransSegs|CurrEstab)|Udp6?_(InDatagrams|OutDatagrams|NoPorts|RcvbufErrors|SndbufErrors))$").String()
)
type netStatCollector struct {
fieldPattern *regexp.Regexp
logger log.Logger
}
func init() {
registerCollector("netstat", defaultEnabled, NewNetStatCollector)
}
// NewNetStatCollector takes and returns
// a new Collector exposing network stats.
func NewNetStatCollector(logger log.Logger) (Collector, error) {
pattern := regexp.MustCompile(*netStatFields)
return &netStatCollector{
fieldPattern: pattern,
logger: logger,
}, nil
}
func (c *netStatCollector) Update(ch chan<- prometheus.Metric) error {
netStats, err := getNetStats(procFilePath("net/netstat"))
if err != nil {
return fmt.Errorf("couldn't get netstats: %w", err)
}
snmpStats, err := getNetStats(procFilePath("net/snmp"))
if err != nil {
return fmt.Errorf("couldn't get SNMP stats: %w", err)
}
snmp6Stats, err := getSNMP6Stats(procFilePath("net/snmp6"))
if err != nil {
return fmt.Errorf("couldn't get SNMP6 stats: %w", err)
}
// Merge the results of snmpStats into netStats (collisions are possible, but
// we know that the keys are always unique for the given use case).
for k, v := range snmpStats {
netStats[k] = v
}
for k, v := range snmp6Stats {
netStats[k] = v
}
for protocol, protocolStats := range netStats {
for name, value := range protocolStats {
key := protocol + "_" + name
v, err := strconv.ParseFloat(value, 64)
if err != nil {
return fmt.Errorf("invalid value %s in netstats: %w", value, err)
}
if !c.fieldPattern.MatchString(key) {
continue
}
ch <- prometheus.MustNewConstMetric(
prometheus.NewDesc(
prometheus.BuildFQName(namespace, netStatsSubsystem, key),
fmt.Sprintf("Statistic %s.", protocol+name),
nil, nil,
),
prometheus.UntypedValue, v,
)
}
}
return nil
}
func getNetStats(fileName string) (map[string]map[string]string, error) {
file, err := os.Open(fileName)
if err != nil {
return nil, err
}
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defer file.Close()
return parseNetStats(file, fileName)
}
func parseNetStats(r io.Reader, fileName string) (map[string]map[string]string, error) {
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var (
netStats = map[string]map[string]string{}
scanner = bufio.NewScanner(r)
)
for scanner.Scan() {
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nameParts := strings.Split(scanner.Text(), " ")
scanner.Scan()
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valueParts := strings.Split(scanner.Text(), " ")
// Remove trailing :.
protocol := nameParts[0][:len(nameParts[0])-1]
netStats[protocol] = map[string]string{}
if len(nameParts) != len(valueParts) {
return nil, fmt.Errorf("mismatch field count mismatch in %s: %s",
fileName, protocol)
}
for i := 1; i < len(nameParts); i++ {
netStats[protocol][nameParts[i]] = valueParts[i]
}
}
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return netStats, scanner.Err()
}
func getSNMP6Stats(fileName string) (map[string]map[string]string, error) {
file, err := os.Open(fileName)
if err != nil {
// On systems with IPv6 disabled, this file won't exist.
// Do nothing.
if errors.Is(err, os.ErrNotExist) {
return nil, nil
}
return nil, err
}
defer file.Close()
return parseSNMP6Stats(file)
}
func parseSNMP6Stats(r io.Reader) (map[string]map[string]string, error) {
var (
netStats = map[string]map[string]string{}
scanner = bufio.NewScanner(r)
)
for scanner.Scan() {
stat := strings.Fields(scanner.Text())
if len(stat) < 2 {
continue
}
// Expect to have "6" in metric name, skip line otherwise
if sixIndex := strings.Index(stat[0], "6"); sixIndex != -1 {
protocol := stat[0][:sixIndex+1]
name := stat[0][sixIndex+1:]
if _, present := netStats[protocol]; !present {
netStats[protocol] = map[string]string{}
}
netStats[protocol][name] = stat[1]
}
}
return netStats, scanner.Err()
}