telegraf/plugins/inputs/procstat/pgrep.go

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package procstat
import (
"fmt"
"io/ioutil"
"os/exec"
"strconv"
"strings"
"github.com/influxdata/telegraf/internal"
)
// Implementation of PIDGatherer that execs pgrep to find processes
type Pgrep struct {
path string
}
func NewPgrep() (PIDFinder, error) {
path, err := exec.LookPath("pgrep")
if err != nil {
return nil, fmt.Errorf("Could not find pgrep binary: %s", err)
}
return &Pgrep{path}, nil
}
func (pg *Pgrep) PidFile(path string) ([]PID, error) {
var pids []PID
pidString, err := ioutil.ReadFile(path)
if err != nil {
return pids, fmt.Errorf("Failed to read pidfile '%s'. Error: '%s'",
path, err)
}
pid, err := strconv.Atoi(strings.TrimSpace(string(pidString)))
if err != nil {
return pids, err
}
pids = append(pids, PID(pid))
return pids, nil
}
func (pg *Pgrep) Pattern(pattern string) ([]PID, error) {
args := []string{pattern}
return find(pg.path, args)
}
func (pg *Pgrep) Uid(user string) ([]PID, error) {
args := []string{"-u", user}
return find(pg.path, args)
}
func (pg *Pgrep) FullPattern(pattern string) ([]PID, error) {
args := []string{"-f", pattern}
return find(pg.path, args)
}
func find(path string, args []string) ([]PID, error) {
out, err := run(path, args)
if err != nil {
return nil, err
}
return parseOutput(out)
}
func run(path string, args []string) (string, error) {
out, err := exec.Command(path, args...).Output()
//if exit code 1, ie no processes found, do not return error
if i, _ := internal.ExitStatus(err); i == 1 {
return "", nil
}
if err != nil {
return "", fmt.Errorf("Error running %s: %s", path, err)
}
return string(out), err
}
func parseOutput(out string) ([]PID, error) {
pids := []PID{}
fields := strings.Fields(out)
for _, field := range fields {
pid, err := strconv.Atoi(field)
if err != nil {
return nil, err
}
if err == nil {
pids = append(pids, PID(pid))
}
}
return pids, nil
}