telegraf/plugins/inputs/fail2ban/fail2ban.go

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package fail2ban
import (
"errors"
"fmt"
"os/exec"
"strings"
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"strconv"
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"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/plugins/inputs"
)
var (
execCommand = exec.Command // execCommand is used to mock commands in tests.
)
type Fail2ban struct {
path string
UseSudo bool
}
var sampleConfig = `
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## Use sudo to run fail2ban-client
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use_sudo = false
`
var metricsTargets = []struct {
target string
field string
}{
{
target: "Currently failed:",
field: "failed",
},
{
target: "Currently banned:",
field: "banned",
},
}
func (f *Fail2ban) Description() string {
return "Read metrics from fail2ban."
}
func (f *Fail2ban) SampleConfig() string {
return sampleConfig
}
func (f *Fail2ban) Gather(acc telegraf.Accumulator) error {
if len(f.path) == 0 {
return errors.New("fail2ban-client not found: verify that fail2ban is installed and that fail2ban-client is in your PATH")
}
name := f.path
var arg []string
if f.UseSudo {
name = "sudo"
arg = append(arg, f.path)
}
args := append(arg, "status")
cmd := execCommand(name, args...)
out, err := cmd.Output()
if err != nil {
return fmt.Errorf("failed to run command %s: %s - %s", strings.Join(cmd.Args, " "), err, string(out))
}
lines := strings.Split(string(out), "\n")
const targetString = "Jail list:"
var jails []string
for _, line := range lines {
idx := strings.LastIndex(line, targetString)
if idx < 0 {
// not target line, skip.
continue
}
jails = strings.Split(strings.TrimSpace(line[idx+len(targetString):]), ", ")
break
}
for _, jail := range jails {
fields := make(map[string]interface{})
args := append(arg, "status", jail)
cmd := execCommand(name, args...)
out, err := cmd.Output()
if err != nil {
return fmt.Errorf("failed to run command %s: %s - %s", strings.Join(cmd.Args, " "), err, string(out))
}
lines := strings.Split(string(out), "\n")
for _, line := range lines {
key, value := extractCount(line)
if key != "" {
fields[key] = value
}
}
acc.AddFields("fail2ban", fields, map[string]string{"jail": jail})
}
return nil
}
func extractCount(line string) (string, int) {
for _, metricsTarget := range metricsTargets {
idx := strings.LastIndex(line, metricsTarget.target)
if idx < 0 {
continue
}
ban := strings.TrimSpace(line[idx+len(metricsTarget.target):])
banCount, err := strconv.Atoi(ban)
if err != nil {
return "", -1
}
return metricsTarget.field, banCount
}
return "", -1
}
func init() {
f := Fail2ban{}
path, _ := exec.LookPath("fail2ban-client")
if len(path) > 0 {
f.path = path
}
inputs.Add("fail2ban", func() telegraf.Input {
f := f
return &f
})
}