mirror of
https://github.com/prometheus/node_exporter.git
synced 2024-11-23 20:36:21 +01:00
6eafa51fa8
* Implement commonalities and linux support for ARP collection * Add ARP collector to fixtures and run as part of e2e tests * Bubble up scanner errors * Use single return values where it makes sense * Add missing annotation * Move arp_common into arp_linux * Add license header to arp_linux.go * Address initial feedback * Use strings.Fields instead of strings.Split * Deal with scanner.Err() rather than throwing away errors * Check for scan errors in-line before interacting with the entries map * Don't interact with potentially empty text from scan * Check for scan errors outside the scan loop * Add comment about moving procfs parsing * Add more direct comment * Update initialism style to match go style guide * Put function args on the same line * Add TODO in front of comment about procfs extraction * Guard against strings.Fields returning an empty slice * Be more defensive about ARP table format and use upcase more broadly * Enable the ARP collector by default * Add ARP collector to the README * Remove 'entry'
103 lines
2.5 KiB
Go
103 lines
2.5 KiB
Go
// Copyright 2017 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// +build !noarp
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package collector
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import (
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"bufio"
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"fmt"
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"io"
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"os"
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"strings"
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"github.com/prometheus/client_golang/prometheus"
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)
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type arpCollector struct {
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entries *prometheus.Desc
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}
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func init() {
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Factories["arp"] = NewARPCollector
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}
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// NewARPCollector returns a new Collector exposing ARP stats.
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func NewARPCollector() (Collector, error) {
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return &arpCollector{
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entries: prometheus.NewDesc(
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prometheus.BuildFQName(Namespace, "arp", "entries"),
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"ARP entries by device",
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[]string{"device"}, nil,
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),
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}, nil
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}
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func getARPEntries() (map[string]uint32, error) {
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file, err := os.Open(procFilePath("net/arp"))
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if err != nil {
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return nil, err
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}
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defer file.Close()
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entries, err := parseARPEntries(file)
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if err != nil {
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return nil, err
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}
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return entries, nil
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}
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// TODO: This should get extracted to the github.com/prometheus/procfs package
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// to support more complete parsing of /proc/net/arp. Instead of adding
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// more fields to this function's return values it should get moved and
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// changed to support each field.
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func parseARPEntries(data io.Reader) (map[string]uint32, error) {
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scanner := bufio.NewScanner(data)
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entries := make(map[string]uint32)
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for scanner.Scan() {
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columns := strings.Fields(scanner.Text())
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if len(columns) < 6 {
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return nil, fmt.Errorf("unexpected ARP table format")
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}
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if columns[0] != "IP" {
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deviceIndex := len(columns) - 1
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entries[columns[deviceIndex]]++
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}
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}
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if err := scanner.Err(); err != nil {
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return nil, fmt.Errorf("failed to parse ARP info: %s", err)
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}
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return entries, nil
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}
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func (c *arpCollector) Update(ch chan<- prometheus.Metric) error {
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entries, err := getARPEntries()
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if err != nil {
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return fmt.Errorf("could not get ARP entries: %s", err)
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}
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for device, entryCount := range entries {
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ch <- prometheus.MustNewConstMetric(
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c.entries, prometheus.GaugeValue, float64(entryCount), device)
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}
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return nil
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}
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