Generated valid label value (Kubernetes) - go

Question

Label values in Kubernetes need to be valid.
See IsValidLabelValue()
For example the input I receive from a rest-API of a provider, which I want to write to a label: Dedicated Server 1U.
Is there a way to generate a valid label via Go from an arbitrary string?

Answer 1

you can have a function to do this, for example:
func generateLabel(input string) string {
input = strings.Replace(input, " ", "-", -1)
return "api-label=" + input
}
the function replaces the spaces in the received string to "-"
you can change the key to any string you like.
you can also add a regex check to make sure that the generated value complies with the label constraints. (this depends if any special characters are being received from the API)
To accept the string even when there are unwanted characters, check the below:
package main
import (
"regexp"
"strings"
"fmt"
)
func generateLabel(input string) string {
input = strings.Replace(input, " ", "-", -1)
re := regexp.MustCompile("[^a-zA-Z0-9-]")
input = re.ReplaceAllString(input, "")
re = regexp.MustCompile("^[^a-zA-Z0-9]([-a-zA-Z0-9]*[a-zA-Z0-9])?$")
input = re.ReplaceAllString(input, "")
return "api-label=" + input
}
func main() {
label := generateLabel("Dedicated Server 1U")
fmt.Println(label) // Output: "api-label=Dedicated-Server-1U"
label1 := generateLabel("Dedicated&test")
fmt.Println(label1) // Output: "api-label=Dedicatedtest"
label2 := generateLabel("Dedicated,test##&(*!great")
fmt.Println(label2) // Output: "api-label=Dedicatedtestgreat"
}