Pubsub Crate

A publish-subscribe system for Rust with async/await support.

This crate provides a simple yet powerful publish-subscribe (pubsub) system that allows multiple subscribers to receive messages published to specific topics. It is designed to be thread-safe, async-friendly, memory-efficient, and supports clean shutdown.

Features

• Thread-safe: Uses Arc and DashMap for concurrent access.
• Async-friendly: Built with async/await support using async-channel.
• Memory efficient: Uses weak references to prevent memory leaks.
• Clean shutdown: Automatically cleans up resources when dropped.
• Multiple subscribers per topic: Supports multiple subscribers for each topic.
• Multiple topics per subscriber: Subscribers can subscribe to multiple topics.
• Graceful shutdown handling: Ensures proper cleanup when the system is dropped.

Usage

Add the following to your Cargo.toml:

[dependencies]
pubsub-rs = "0.1.0"

Basic Example

use pubsub::{Pubsub, PubsubError};

#[tokio::main]
async fn main() {
    let pubsub = Pubsub::new();

    // Subscribe to topics
    let subscriber = pubsub.subscribe(vec!["topic1", "topic2"]).await;

    // Publish messages
    pubsub.publish("topic1", "Hello".to_owned()).await;

    // Receive messages
    let (topic, message) = subscriber.recv().await.unwrap();
    assert_eq!(topic, "topic1");
    assert_eq!(message, "Hello");
}

Error Handling

The main error type is PubsubError, which occurs when:

• The pubsub system has been closed.
• A subscriber tries to receive messages after the pubsub system is dropped.

Performance Considerations

• Uses DashMap for concurrent topic storage.
• Each subscriber has its own async channel.
• Message delivery is non-blocking.
• Automatic cleanup of dropped subscribers.

Safety

• All operations are thread-safe.
• Uses Arc for shared ownership.
• Uses Weak references to prevent memory leaks.
• Proper cleanup on drop.

Examples

See the tests module for more comprehensive usage examples.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Contributing

Contributions are welcome! Please open an issue or submit a pull request on GitHub.

Acknowledgements

• async-channel for providing the async channels used in this crate.
• DashMap for providing the concurrent hash map used for topic storage.