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exec.go
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exec.go
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package exec
import (
"bytes"
"fmt"
"os/exec"
"path/filepath"
"runtime"
"strings"
"sync"
"time"
"github.com/kballard/go-shellquote"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/internal"
"github.com/influxdata/telegraf/plugins/inputs"
"github.com/influxdata/telegraf/plugins/parsers"
"github.com/influxdata/telegraf/plugins/parsers/nagios"
)
const sampleConfig = `
## Commands array
commands = [
"/tmp/test.sh",
"/usr/bin/mycollector --foo=bar",
"/tmp/collect_*.sh"
]
## Timeout for each command to complete.
timeout = "5s"
## measurement name suffix (for separating different commands)
name_suffix = "_mycollector"
## Data format to consume.
## Each data format has its own unique set of configuration options, read
## more about them here:
## https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_INPUT.md
data_format = "influx"
`
const MaxStderrBytes = 512
type Exec struct {
Commands []string
Command string
Timeout internal.Duration
parser parsers.Parser
runner Runner
log telegraf.Logger
}
func NewExec() *Exec {
return &Exec{
runner: CommandRunner{},
Timeout: internal.Duration{Duration: time.Second * 5},
}
}
type Runner interface {
Run(string, time.Duration) ([]byte, []byte, error)
}
type CommandRunner struct{}
func (c CommandRunner) Run(
command string,
timeout time.Duration,
) ([]byte, []byte, error) {
split_cmd, err := shellquote.Split(command)
if err != nil || len(split_cmd) == 0 {
return nil, nil, fmt.Errorf("exec: unable to parse command, %s", err)
}
cmd := exec.Command(split_cmd[0], split_cmd[1:]...)
var (
out bytes.Buffer
stderr bytes.Buffer
)
cmd.Stdout = &out
cmd.Stderr = &stderr
runErr := internal.RunTimeout(cmd, timeout)
out = removeCarriageReturns(out)
if stderr.Len() > 0 {
stderr = removeCarriageReturns(stderr)
stderr = truncate(stderr)
}
return out.Bytes(), stderr.Bytes(), runErr
}
func truncate(buf bytes.Buffer) bytes.Buffer {
// Limit the number of bytes.
didTruncate := false
if buf.Len() > MaxStderrBytes {
buf.Truncate(MaxStderrBytes)
didTruncate = true
}
if i := bytes.IndexByte(buf.Bytes(), '\n'); i > 0 {
// Only show truncation if the newline wasn't the last character.
if i < buf.Len()-1 {
didTruncate = true
}
buf.Truncate(i)
}
if didTruncate {
buf.WriteString("...")
}
return buf
}
// removeCarriageReturns removes all carriage returns from the input if the
// OS is Windows. It does not return any errors.
func removeCarriageReturns(b bytes.Buffer) bytes.Buffer {
if runtime.GOOS == "windows" {
var buf bytes.Buffer
for {
byt, er := b.ReadBytes(0x0D)
end := len(byt)
if nil == er {
end -= 1
}
if nil != byt {
buf.Write(byt[:end])
} else {
break
}
if nil != er {
break
}
}
b = buf
}
return b
}
func (e *Exec) ProcessCommand(command string, acc telegraf.Accumulator, wg *sync.WaitGroup) {
defer wg.Done()
_, isNagios := e.parser.(*nagios.NagiosParser)
out, errbuf, runErr := e.runner.Run(command, e.Timeout.Duration)
if !isNagios && runErr != nil {
err := fmt.Errorf("exec: %s for command '%s': %s", runErr, command, string(errbuf))
acc.AddError(err)
return
}
metrics, err := e.parser.Parse(out)
if err != nil {
acc.AddError(err)
return
}
if isNagios {
metrics, err = nagios.TryAddState(runErr, metrics)
if err != nil {
e.log.Errorf("failed to add nagios state: %s", err)
}
}
for _, m := range metrics {
acc.AddMetric(m)
}
}
func (e *Exec) SampleConfig() string {
return sampleConfig
}
func (e *Exec) Description() string {
return "Read metrics from one or more commands that can output to stdout"
}
func (e *Exec) SetParser(parser parsers.Parser) {
e.parser = parser
}
func (e *Exec) Gather(acc telegraf.Accumulator) error {
var wg sync.WaitGroup
// Legacy single command support
if e.Command != "" {
e.Commands = append(e.Commands, e.Command)
e.Command = ""
}
commands := make([]string, 0, len(e.Commands))
for _, pattern := range e.Commands {
cmdAndArgs := strings.SplitN(pattern, " ", 2)
if len(cmdAndArgs) == 0 {
continue
}
matches, err := filepath.Glob(cmdAndArgs[0])
if err != nil {
acc.AddError(err)
continue
}
if len(matches) == 0 {
// There were no matches with the glob pattern, so let's assume
// that the command is in PATH and just run it as it is
commands = append(commands, pattern)
} else {
// There were matches, so we'll append each match together with
// the arguments to the commands slice
for _, match := range matches {
if len(cmdAndArgs) == 1 {
commands = append(commands, match)
} else {
commands = append(commands,
strings.Join([]string{match, cmdAndArgs[1]}, " "))
}
}
}
}
wg.Add(len(commands))
for _, command := range commands {
go e.ProcessCommand(command, acc, &wg)
}
wg.Wait()
return nil
}
func (e *Exec) Init() error {
return nil
}
func init() {
inputs.Add("exec", func() telegraf.Input {
return NewExec()
})
}