vitess-gh/go/vt/servenv/pid_file.go

62 строки
1.4 KiB
Go

/*
Copyright 2019 The Vitess Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package servenv
import (
"flag"
"fmt"
"os"
"vitess.io/vitess/go/vt/log"
)
var pidFile = flag.String("pid_file", "", "If set, the process will write its pid to the named file, and delete it on graceful shutdown.")
func init() {
pidFileCreated := false
// Create pid file after flags are parsed.
OnInit(func() {
if *pidFile == "" {
return
}
file, err := os.OpenFile(*pidFile, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0666)
if err != nil {
log.Errorf("Unable to create pid file '%s': %v", *pidFile, err)
return
}
pidFileCreated = true
fmt.Fprintln(file, os.Getpid())
file.Close()
})
// Remove pid file on graceful shutdown.
OnClose(func() {
if *pidFile == "" {
return
}
if !pidFileCreated {
return
}
if err := os.Remove(*pidFile); err != nil {
log.Errorf("Unable to remove pid file '%s': %v", *pidFile, err)
}
})
}