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package util
import (
"math/rand" // not crypto secure
"regexp"
)
const randHostnameCharset = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-"
const randStringCharset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
var (
// Up to 15 characters; only letters, digits, and hyphens (with hyphens not at the start or end).
randHostnameRegex = regexp.MustCompile(`^[a-zA-Z][a-zA-Z0-9-]{0,14}[a-zA-Z0-9]$`)
)
func RandomHostname() (hostname string) {
for {
// between 2 and 10 characters
if hostname = RandomStringFromCharset(randHostnameCharset, rand.Intn(8)+2); randHostnameRegex.MatchString(hostname) {
return
}
}
}
func RandomString() string {
return RandomStringFromCharset(randStringCharset, rand.Intn(10)+6)
}
func RandomStringFromCharset(charset string, length int) string {
b := make([]byte, length)
for i := range length {
b[i] = charset[rand.Intn(len(charset))]
}
return string(b)
}
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