forked from hashicorp/packer
/
randomstring.go
45 lines (39 loc) · 900 Bytes
/
randomstring.go
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package common
import (
"math/rand"
"os"
"time"
)
var pwSymbols = []string{
"abcdefghijklmnopqrstuvwxyz",
"ABCDEFGHIJKLMNOPQRSTUVWXYZ",
"0123456789",
}
var rnd = rand.New(rand.NewSource(time.Now().UnixNano() + int64(os.Getpid())))
func RandomString(chooseFrom string, length int) (randomString string) {
cflen := len(chooseFrom)
for i := 0; i < length; i++ {
randomString += string(chooseFrom[rnd.Intn(cflen)])
}
return
}
func RandomPassword() (password string) {
pwlen := 15
batchsize := pwlen / len(pwSymbols)
pw := make([]byte, 0, pwlen)
// choose character set
for c := 0; len(pw) < pwlen; c++ {
s := RandomString(pwSymbols[c%len(pwSymbols)], rnd.Intn(batchsize-1)+1)
pw = append(pw, []byte(s)...)
}
// truncate
pw = pw[:pwlen]
// permute
for c := 0; c < pwlen-1; c++ {
i := rnd.Intn(pwlen-c) + c
x := pw[c]
pw[c] = pw[i]
pw[i] = x
}
return string(pw)
}