Generate a user token for the new jenkins subsystem (works in 2.139+)

gistfile1.txt

import jenkins.security.*
import jenkins.security.apitoken.*
 
def username = '<pre-existing user goes here>'
def token = '<what you want to name your token>'
User u = User.get(username)

ApiTokenProperty p = u.getProperty(ApiTokenProperty.class);

ApiTokenStore.TokenUuidAndPlainValue tokenUuidAndPlainValue = p.tokenStore.generateNewToken(token);
u.save()

// Here's the token output value.
println tokenUuidAndPlainValue.plainValue