telegraf/plugins/inputs/pf/pf.go

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package pf
import (
"bufio"
"fmt"
"os/exec"
"regexp"
"strconv"
"strings"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/plugins/inputs"
)
const measurement = "pf"
const pfctlCommand = "pfctl"
type PF struct {
PfctlCommand string
PfctlArgs []string
UseSudo bool
StateTable []*Entry
infoFunc func() (string, error)
}
func (pf *PF) Description() string {
return "Gather counters from PF"
}
func (pf *PF) SampleConfig() string {
return `
## PF require root access on most systems.
## Setting 'use_sudo' to true will make use of sudo to run pfctl.
## Users must configure sudo to allow telegraf user to run pfctl with no password.
## pfctl can be restricted to only list command "pfctl -s info".
use_sudo = false
`
}
// Gather is the entrypoint for the plugin.
func (pf *PF) Gather(acc telegraf.Accumulator) error {
if pf.PfctlCommand == "" {
var err error
if pf.PfctlCommand, pf.PfctlArgs, err = pf.buildPfctlCmd(); err != nil {
acc.AddError(fmt.Errorf("Can't construct pfctl commandline: %s", err))
return nil
}
}
o, err := pf.infoFunc()
if err != nil {
acc.AddError(err)
return nil
}
if perr := pf.parsePfctlOutput(o, acc); perr != nil {
acc.AddError(perr)
}
return nil
}
var errParseHeader = fmt.Errorf("Cannot find header in %s output", pfctlCommand)
func errMissingData(tag string) error {
return fmt.Errorf("struct data for tag \"%s\" not found in %s output", tag, pfctlCommand)
}
type pfctlOutputStanza struct {
HeaderRE *regexp.Regexp
ParseFunc func([]string, telegraf.Accumulator) error
Found bool
}
var pfctlOutputStanzas = []*pfctlOutputStanza{
&pfctlOutputStanza{
HeaderRE: regexp.MustCompile("^State Table"),
ParseFunc: parseStateTable,
},
}
var anyTableHeaderRE = regexp.MustCompile("^[A-Z]")
func (pf *PF) parsePfctlOutput(pfoutput string, acc telegraf.Accumulator) error {
scanner := bufio.NewScanner(strings.NewReader(pfoutput))
for scanner.Scan() {
line := scanner.Text()
for _, s := range pfctlOutputStanzas {
if s.HeaderRE.MatchString(line) {
var stanzaLines []string
scanner.Scan()
line = scanner.Text()
for !anyTableHeaderRE.MatchString(line) {
stanzaLines = append(stanzaLines, line)
scanner.Scan()
line = scanner.Text()
}
if perr := s.ParseFunc(stanzaLines, acc); perr != nil {
return perr
}
s.Found = true
}
}
}
for _, s := range pfctlOutputStanzas {
if !s.Found {
return errParseHeader
}
}
return nil
}
type Entry struct {
Field string
PfctlTitle string
Value int64
}
var StateTable = []*Entry{
&Entry{"entries", "current entries", -1},
&Entry{"searches", "searches", -1},
&Entry{"inserts", "inserts", -1},
&Entry{"removals", "removals", -1},
}
var stateTableRE = regexp.MustCompile(`^ (.*?)\s+(\d+)`)
func parseStateTable(lines []string, acc telegraf.Accumulator) error {
for _, v := range lines {
entries := stateTableRE.FindStringSubmatch(v)
if entries != nil {
for _, f := range StateTable {
if f.PfctlTitle == entries[1] {
var err error
if f.Value, err = strconv.ParseInt(entries[2], 10, 64); err != nil {
return err
}
}
}
}
}
fields := make(map[string]interface{})
for _, v := range StateTable {
if v.Value == -1 {
return errMissingData(v.PfctlTitle)
}
fields[v.Field] = v.Value
}
acc.AddFields(measurement, fields, make(map[string]string))
return nil
}
func (pf *PF) callPfctl() (string, error) {
cmd := execCommand(pf.PfctlCommand, pf.PfctlArgs...)
out, oerr := cmd.Output()
if oerr != nil {
ee, ok := oerr.(*exec.ExitError)
if !ok {
return string(out), fmt.Errorf("error running %s: %s: (unable to get stderr)", pfctlCommand, oerr)
}
return string(out), fmt.Errorf("error running %s: %s: %s", pfctlCommand, oerr, ee.Stderr)
}
return string(out), oerr
}
var execLookPath = exec.LookPath
var execCommand = exec.Command
func (pf *PF) buildPfctlCmd() (string, []string, error) {
cmd, err := execLookPath(pfctlCommand)
if err != nil {
return "", nil, fmt.Errorf("can't locate %s: %v", pfctlCommand, err)
}
args := []string{"-s", "info"}
if pf.UseSudo {
args = append([]string{cmd}, args...)
cmd, err = execLookPath("sudo")
if err != nil {
return "", nil, fmt.Errorf("can't locate sudo: %v", err)
}
}
return cmd, args, nil
}
func init() {
inputs.Add("pf", func() telegraf.Input {
pf := new(PF)
pf.infoFunc = pf.callPfctl
return pf
})
}