telegraf/plugins/exec/exec.go

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package exec
import (
"bytes"
"encoding/json"
"fmt"
"github.com/gonuts/go-shellquote"
"github.com/influxdb/telegraf/plugins"
"os/exec"
"sync"
)
const sampleConfig = `
# specify commands via an array of tables
[[exec.commands]]
# the command to run
command = "/usr/bin/mycollector --foo=bar"
# name of the command (used as a prefix for measurements)
name = "mycollector"
`
type Command struct {
Command string
Name string
}
type Exec struct {
Commands []*Command
runner Runner
}
type Runner interface {
Run(string, ...string) ([]byte, error)
}
type CommandRunner struct {
}
func NewExec() *Exec {
return &Exec{runner: CommandRunner{}}
}
func (c CommandRunner) Run(command string, args ...string) ([]byte, error) {
cmd := exec.Command(command, args...)
var out bytes.Buffer
cmd.Stdout = &out
if err := cmd.Run(); err != nil {
return nil, fmt.Errorf("exec: %s for command '%s'", err, command)
}
return out.Bytes(), nil
}
func (e *Exec) SampleConfig() string {
return sampleConfig
}
func (e *Exec) Description() string {
return "Read flattened metrics from one or more commands that output JSON to stdout"
}
func (e *Exec) Gather(acc plugins.Accumulator) error {
var wg sync.WaitGroup
var outerr error
for _, c := range e.Commands {
wg.Add(1)
go func(c *Command, acc plugins.Accumulator) {
defer wg.Done()
outerr = e.gatherCommand(c, acc)
}(c, acc)
}
wg.Wait()
return outerr
}
func (e *Exec) gatherCommand(c *Command, acc plugins.Accumulator) error {
words, err := shellquote.Split(c.Command)
if err != nil || len(words) == 0 {
return fmt.Errorf("exec: unable to parse command, %s", err)
}
out, err := e.runner.Run(words[0], words[1:]...)
if err != nil {
return err
}
var jsonOut interface{}
err = json.Unmarshal(out, &jsonOut)
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if err != nil {
return fmt.Errorf("exec: unable to parse output of '%s' as JSON, %s", c.Command, err)
}
processResponse(acc, c.Name, map[string]string{}, jsonOut)
return nil
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}
func processResponse(acc plugins.Accumulator, prefix string, tags map[string]string, v interface{}) {
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switch t := v.(type) {
case map[string]interface{}:
for k, v := range t {
processResponse(acc, prefix+"_"+k, tags, v)
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}
case float64:
acc.Add(prefix, v, tags)
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}
}
func init() {
plugins.Add("exec", func() plugins.Plugin {
return NewExec()
})
}