package main

import (
    "log"

    casbin "github.com/casbin/casbin/v2"
    etcdwatcher "github.com/casbin/etcd-watcher/v2"
)

func updateCallback(rev string) {
    log.Println("New revision detected:", rev)
}

func main() {
    // Initialize the watcher.
    // Use the endpoint of etcd cluster as parameter.
    w, _ := etcdwatcher.NewWatcher([]string{"http://127.0.0.1:2379"}, "keyname")
    
    // Initialize the enforcer.
    e, _ := casbin.NewEnforcer("examples/rbac_model.conf", "examples/rbac_policy.csv")
    
    // Set the watcher for the enforcer.
    e.SetWatcher(w)
    
    // By default, the watcher's callback is automatically set to the
    // enforcer's LoadPolicy() in the SetWatcher() call.
    // We can change it by explicitly setting a callback.
    w.SetUpdateCallback(updateCallback)
    
    // Update the policy to test the effect.
    // You should see "[New revision detected: X]" in the log.
    e.SavePolicy()
}