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moby--moby/pkg/pidfile/pidfile.go
Vincent Demeester 18c7c67308 Lint on pkg/* packages
- pkg/useragent
- pkg/units
- pkg/ulimit
- pkg/truncindex
- pkg/timeoutconn
- pkg/term
- pkg/tarsum
- pkg/tailfile
- pkg/systemd
- pkg/stringutils
- pkg/stringid
- pkg/streamformatter
- pkg/sockets
- pkg/signal
- pkg/proxy
- pkg/progressreader
- pkg/pools
- pkg/plugins
- pkg/pidfile
- pkg/parsers
- pkg/parsers/filters
- pkg/parsers/kernel
- pkg/parsers/operatingsystem

Signed-off-by: Vincent Demeester <vincent@sbr.pm>
2015-07-27 21:26:21 +02:00

48 lines
1.2 KiB
Go

// Package pidfile 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 pidfile
import (
"fmt"
"io/ioutil"
"os"
"path/filepath"
"strconv"
)
// PIDFile is a file used to store the process ID of a running process.
type PIDFile struct {
path string
}
func checkPIDFileAlreadyExists(path string) error {
if pidString, err := ioutil.ReadFile(path); err == nil {
if pid, err := strconv.Atoi(string(pidString)); err == nil {
if _, err := os.Stat(filepath.Join("/proc", string(pid))); err == nil {
return fmt.Errorf("pid file found, ensure docker is not running or delete %s", path)
}
}
}
return nil
}
// New creates a PIDfile using the specified path.
func New(path string) (*PIDFile, 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 &PIDFile{path: path}, nil
}
// Remove removes the PIDFile.
func (file PIDFile) Remove() error {
if err := os.Remove(file.path); err != nil {
return err
}
return nil
}