47 lines
1.0 KiB
Go
47 lines
1.0 KiB
Go
|
package lib
|
||
|
|
|
||
|
|
import (
|
||
|
|
"errors"
|
||
|
|
"fmt"
|
||
|
|
"os"
|
||
|
|
"time"
|
||
|
|
)
|
||
|
|
|
||
|
|
type uniqueName struct {
|
||
|
|
now time.Time
|
||
|
|
}
|
||
|
|
|
||
|
|
// generate will create and return unique file names for new messages
|
||
|
|
func generate() (string, error) {
|
||
|
|
uni := &uniqueName{now: time.Now()}
|
||
|
|
hostname, err := uni.right()
|
||
|
|
if err != nil {
|
||
|
|
return "", errors.New("Failed to fetch hostname")
|
||
|
|
}
|
||
|
|
|
||
|
|
return fmt.Sprintf("%d.%s.%s", uni.left(), uni.middle(), hostname), nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// left part of the unique name is the number of seconds since the UNIX epoch
|
||
|
|
func (uni *uniqueName) left() int64 {
|
||
|
|
return uni.now.Unix()
|
||
|
|
}
|
||
|
|
|
||
|
|
func (uni *uniqueName) microseconds() int64 {
|
||
|
|
return uni.now.Unix() * 1000000
|
||
|
|
}
|
||
|
|
|
||
|
|
// middle part of the unique name contains microsecond, process id, and a per-process incrementing counter
|
||
|
|
func (uni *uniqueName) middle() string {
|
||
|
|
return fmt.Sprintf("M%06dP%dQ%d", uni.microseconds(), os.Getpid(), getCounter())
|
||
|
|
}
|
||
|
|
|
||
|
|
// right part is the hostname
|
||
|
|
func (uni *uniqueName) right() (string, error) {
|
||
|
|
name, err := os.Hostname()
|
||
|
|
if err != nil {
|
||
|
|
return "", err
|
||
|
|
}
|
||
|
|
return name, nil
|
||
|
|
}
|