Script to grant users permissions on Jenkins. You need to install matrix-auth if you want to use it

access-control.json

{
    "users":[
        {
            "username": "user1",
            "role": "master"
        },
        {
            "username": "user2",
            "role": "master"
        },
        {
            "username": "user3",
            "role": "authenticated"
        }
    ]
}

permission.groovy

#!groovy

import jenkins.*
import hudson.*
import jenkins.model.*
import hudson.model.*
import hudson.security.*
import com.cloudbees.plugins.credentials.*
import groovy.json.*

masterRole = [
    com.cloudbees.plugins.credentials.CredentialsProvider.CREATE,
    com.cloudbees.plugins.credentials.CredentialsProvider.DELETE,
    com.cloudbees.plugins.credentials.CredentialsProvider.MANAGE_DOMAINS,
    com.cloudbees.plugins.credentials.CredentialsProvider.UPDATE,
    com.cloudbees.plugins.credentials.CredentialsProvider.VIEW,
    hudson.model.Computer.BUILD,
    hudson.model.Computer.CONFIGURE,
    hudson.model.Computer.CONNECT,
    hudson.model.Computer.CREATE,
    hudson.model.Computer.DELETE,
    hudson.model.Computer.DISCONNECT,
    hudson.model.Hudson.ADMINISTER,
    hudson.model.Hudson.READ,
    hudson.model.Item.BUILD,
    hudson.model.Item.CANCEL,
    hudson.model.Item.CONFIGURE,
    hudson.model.Item.CREATE,
    hudson.model.Item.DELETE,
    hudson.model.Item.DISCOVER,
    hudson.model.Item.READ,
    hudson.model.Item.WORKSPACE,
    hudson.model.Item.EXTENDED_READ,
    hudson.model.Run.DELETE,
    hudson.model.Run.UPDATE,
    hudson.model.View.CONFIGURE,
    hudson.model.View.CREATE,
    hudson.model.View.DELETE,
    hudson.model.View.READ,
    hudson.scm.SCM.TAG
]

authenticatedRole = [
    com.cloudbees.plugins.credentials.CredentialsProvider.VIEW,
    hudson.model.Hudson.READ,
    hudson.model.Item.BUILD,
    hudson.model.Item.CANCEL,
    hudson.model.Item.CONFIGURE,
    hudson.model.Item.CREATE,
    hudson.model.Item.DISCOVER,
    hudson.model.Item.READ,
    hudson.model.Item.WORKSPACE,
    hudson.model.Run.UPDATE,
    hudson.model.View.CONFIGURE,
    hudson.model.View.CREATE,
    hudson.model.View.DELETE,
    hudson.model.View.READ
]

def jsonSlurper = new JsonSlurper()
def reader = new BufferedReader(new InputStreamReader(new FileInputStream("/run/secrets/access-control.json"),"UTF-8"))
data = jsonSlurper.parse(reader)

def instance = Jenkins.getInstance()
instance.setSecurityRealm(new HudsonPrivateSecurityRealm(false))


def strategy = new GlobalMatrixAuthorizationStrategy()

strategy.add(Jenkins.ADMINISTER, "admin")

data.users.each { user->
    println "username " + user.username
    println "role " + user.role

    def roles
    switch(user.role) {
        case "master":
            roles = masterRole
        break
        case "authenticated":
            roles = authenticatedRole
        break
    }

    roles.each { role->
        strategy.add(role, user.username)
    }

    println "The user " + user.username + " was granted with the permission " + user.role
}

instance.setAuthorizationStrategy(strategy)
instance.save()