rclone/vendor/github.com/pengsrc/go-shared/pid/pidfile.go
2018-01-16 13:20:59 +00:00

47 lines
1.1 KiB
Go

// Package pid provides structure and helper functions to create and remove
// PID file. A PID file is usually a file used to store the process ID of a
// running process.
package pid
import (
"fmt"
"io/ioutil"
"os"
"strconv"
"strings"
)
// File is a file used to store the process ID of a running process.
type File struct {
path string
}
func checkPIDFileAlreadyExists(path string) error {
if pidByte, err := ioutil.ReadFile(path); err == nil {
pidString := strings.TrimSpace(string(pidByte))
if pid, err := strconv.Atoi(pidString); err == nil {
if processExists(pid) {
return fmt.Errorf("pid file found, ensure server is not running or delete %s", path)
}
}
}
return nil
}
// New creates a PID file using the specified path.
func New(path string) (*File, error) {
if err := checkPIDFileAlreadyExists(path); err != nil {
return nil, err
}
if err := ioutil.WriteFile(path, []byte(fmt.Sprintf("%d", os.Getpid())), 0644); err != nil {
return nil, err
}
return &File{path: path}, nil
}
// Remove removes the File.
func (file File) Remove() error {
return os.Remove(file.path)
}