90 lines
1.7 KiB
Go
90 lines
1.7 KiB
Go
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// Package pidfile manages pid files.
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package pidfile
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import (
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"bytes"
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"errors"
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"flag"
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"fmt"
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"io/ioutil"
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"os"
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"path/filepath"
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"strconv"
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"github.com/facebookgo/atomicfile"
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)
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var (
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errNotConfigured = errors.New("pidfile not configured")
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pidfile = flag.String("pidfile", "", "If specified, write pid to file.")
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)
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// IsNotConfigured returns true if the error indicates the pidfile location has
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// not been configured.
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func IsNotConfigured(err error) bool {
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if err == errNotConfigured {
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return true
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}
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return false
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}
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// GetPidfilePath returns the configured pidfile path.
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func GetPidfilePath() string {
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return *pidfile
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}
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// SetPidfilePath sets the pidfile path.
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func SetPidfilePath(p string) {
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*pidfile = p
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}
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// Write the pidfile based on the flag. It is an error if the pidfile hasn't
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// been configured.
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func Write() error {
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if *pidfile == "" {
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return errNotConfigured
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}
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if err := os.MkdirAll(filepath.Dir(*pidfile), os.FileMode(0755)); err != nil {
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return err
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}
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file, err := atomicfile.New(*pidfile, os.FileMode(0644))
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if err != nil {
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return fmt.Errorf("error opening pidfile %s: %s", *pidfile, err)
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}
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defer file.Close() // in case we fail before the explicit close
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_, err = fmt.Fprintf(file, "%d", os.Getpid())
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if err != nil {
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return err
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}
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err = file.Close()
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if err != nil {
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return err
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}
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return nil
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}
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// Read the pid from the configured file. It is an error if the pidfile hasn't
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// been configured.
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func Read() (int, error) {
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if *pidfile == "" {
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return 0, errNotConfigured
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}
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d, err := ioutil.ReadFile(*pidfile)
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if err != nil {
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return 0, err
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}
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pid, err := strconv.Atoi(string(bytes.TrimSpace(d)))
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if err != nil {
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return 0, fmt.Errorf("error parsing pid from %s: %s", *pidfile, err)
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}
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return pid, nil
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}
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