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.

pubsub-rs 0.1.1