73 lines
1.7 KiB
Go
73 lines
1.7 KiB
Go
package main
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import (
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"fmt"
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"io/ioutil"
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"log"
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"os"
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"path/filepath"
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"strconv"
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"strings"
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processInfo "github.com/shirou/gopsutil/process"
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)
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func checkAndCreateInstanceLock(name string) (pid int32, err error) {
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lockFilePath := filepath.Join(*databaseRootDir, fmt.Sprintf("%s-lock.pid", name))
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// read current pid file
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data, err := ioutil.ReadFile(lockFilePath)
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if err != nil {
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if os.IsNotExist(err) {
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// create new lock
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return 0, createInstanceLock(lockFilePath)
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}
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return 0, err
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}
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// file exists!
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parsedPid, err := strconv.ParseInt(strings.TrimSpace(string(data)), 10, 64)
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if err != nil {
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log.Printf("failed to parse existing lock pid file (ignoring): %s\n", err)
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return 0, createInstanceLock(lockFilePath)
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}
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log.Printf("===== checking if PID %d exists\n", int32(parsedPid))
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// check if process exists
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p, err := processInfo.NewProcess(int32(parsedPid))
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if err == nil {
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// TODO: remove this workaround as soon as NewProcess really returns an error on windows when the process does not exist
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// Issue: https://github.com/shirou/gopsutil/issues/729
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_, err = p.Name()
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if err == nil {
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// process exists
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return p.Pid, nil
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}
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}
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// else create new lock
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return 0, createInstanceLock(lockFilePath)
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}
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func createInstanceLock(lockFilePath string) error {
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// create database dir
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err := os.MkdirAll(*databaseRootDir, 0777)
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if err != nil {
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log.Printf("failed to create base folder: %s\n", err)
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}
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// create lock file
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err = ioutil.WriteFile(lockFilePath, []byte(fmt.Sprintf("%d", os.Getpid())), 0666)
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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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func deleteInstanceLock(name string) error {
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lockFilePath := filepath.Join(*databaseRootDir, fmt.Sprintf("%s-lock.pid", name))
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return os.Remove(lockFilePath)
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}
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