watcher

Casbin Watermill Watcher

This is a Casbin watcher based on Watermill, a Go library for working efficiently with message streams. With Watermill's support for various Pub/Sub backends, this watcher allows for flexible integration with numerous messaging systems.

Installation

go get github.com/origadmin/casbin-watcher/v3

Usage

To use the watcher, you need to create a new watcher instance with a connection URL that specifies the driver and its configuration.

import (
"context"
"log"

"github.com/casbin/casbin/v3"
"github.com/origadmin/casbin-watcher/v3"
// Import the specific driver you want to use
_ "github.com/origadmin/casbin-watcher/v3/drivers/nats" // Corrected import path
)

func main() {
// The connection URL for the desired driver.
// See the driver's README for configuration details.
connectionURL := "nats://localhost:4222/casbin_updates" // Corrected NATS URL

// Create a new watcher.
w, err := watcher.NewWatcher(context.Background(), connectionURL) // Removed topic argument
if err != nil {
log.Fatalf("Failed to create watcher: %v", err)
}

// Initialize the enforcer.
e, err := casbin.NewEnforcer("model.conf", "policy.csv")
if err != nil {
log.Fatalf("Failed to create enforcer: %v", err)
}

// Set the watcher for the enforcer.
err = e.SetWatcher(w)
if err != nil {
log.Fatalf("Failed to set watcher: %v", err)
}

// The watcher will now automatically update other enforcer instances
// when the policy changes.
// For example, after e.SavePolicy() or e.AddPolicy(), etc.
}

Supported Drivers

This section lists all Watermill Pub/Sub backends, indicating their implementation status within this casbin-watcher repository.

WatcherEx

This library also supports WatcherEx for more granular policy update notifications.

// Create a new WatcherEx instance
w, err := watcher.NewWatcherEx(context.Background(), connectionURL)
if err != nil {
// ...
}

// Now you can use methods like:
// w.UpdateForAddPolicy(...)
// w.UpdateForRemovePolicy(...)