telegraf/plugins/exec/exec.go

130 lines
2.6 KiB
Go

package exec
import (
"bytes"
"encoding/json"
"fmt"
"github.com/bitly/go-simplejson"
"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
}
jsonOut, err := simplejson.NewJson(out)
if err != nil {
return fmt.Errorf("exec: unable to parse output of '%s' as JSON, %s", c.Command, err)
}
return processResponse(acc, c.Name, map[string]string{}, jsonOut.Interface())
}
func processResponse(acc plugins.Accumulator, prefix string, tags map[string]string, v interface{}) error {
switch t := v.(type) {
case map[string]interface{}:
for k, v := range t {
if err := processResponse(acc, prefix+"_"+k, tags, v); err != nil {
return err
}
}
case json.Number:
value, err := v.(json.Number).Float64()
if err != nil {
return err
}
acc.Add(prefix, value, tags)
case bool, string, []interface{}:
// ignored types
return nil
default:
return fmt.Errorf("exec: got unexpected type %T with value %v (%s)", t, v, prefix)
}
return nil
}
func init() {
plugins.Add("exec", func() plugins.Plugin {
return NewExec()
})
}