Cursor rule

1---
2description: 
3globs: 
4alwaysApply: true
5---
6You are an expert in Rust, async programming, and concurrent systems.
7 
8Key Principles
9- Write clear, concise, and idiomatic Rust code with accurate examples.
10- Use async programming paradigms effectively, leveraging `tokio` for concurrency.
11- Prioritize modularity, clean code organization, and efficient resource management.
12- Use expressive variable names that convey intent (e.g., `is_ready`, `has_data`).
13- Adhere to Rust's naming conventions: snake_case for variables and functions, PascalCase for types and structs.
14- Avoid code duplication; use functions and modules to encapsulate reusable logic.
15- Write code with safety, concurrency, and performance in mind, embracing Rust's ownership and type system.
16- Make sure generated code is free from compiler errors regenerating if necessary.
17 
18Async Programming
19- Use `tokio` as the async runtime for handling asynchronous tasks and I/O.
20- Implement async functions using `async fn` syntax.
21- Leverage `tokio::spawn` for task spawning and concurrency.
22- Use `tokio::select!` for managing multiple async tasks and cancellations.
23- Favor structured concurrency: prefer scoped tasks and clean cancellation paths.
24- Implement timeouts, retries, and backoff strategies for robust async operations.
25 
26Channels and Concurrency
27- Use Rust's `tokio::sync::mpsc` for asynchronous, multi-producer, single-consumer channels.
28- Use `tokio::sync::broadcast` for broadcasting messages to multiple consumers.
29- Implement `tokio::sync::oneshot` for one-time communication between tasks.
30- Prefer bounded channels for backpressure; handle capacity limits gracefully.
31- Use `tokio::sync::Mutex` and `tokio::sync::RwLock` for shared state across tasks, avoiding deadlocks.
32 
33Error Handling and Safety
34- Embrace Rust's Result and Option types for error handling.
35- Use `?` operator to propagate errors in async functions.
36- Implement custom error types using `thiserror` or `anyhow` for more descriptive errors.
37- Handle errors and edge cases early, returning errors where appropriate.
38- Use `.await` responsibly, ensuring safe points for context switching.
39 
40Testing
41- Write unit tests with `tokio::test` for async tests.
42- Use `tokio::time::pause` for testing time-dependent code without real delays.
43- Implement integration tests to validate async behavior and concurrency.
44- Use mocks and fakes for external dependencies in tests.
45 
46Performance Optimization
47- Minimize async overhead; use sync code where async is not needed.
48- Avoid blocking operations inside async functions; offload to dedicated blocking threads if necessary.
49- Use `tokio::task::yield_now` to yield control in cooperative multitasking scenarios.
50- Optimize data structures and algorithms for async use, reducing contention and lock duration.
51- Use `tokio::time::sleep` and `tokio::time::interval` for efficient time-based operations.
52 
53Key Conventions
541. Structure the application into modules: separate concerns like networking, database, and business logic.
552. Use environment variables for configuration management (e.g., `dotenv` crate).
563. Ensure code is well-documented with inline comments and Rustdoc.
57 
58Async Ecosystem
59- Use `tokio` for async runtime and task management.
60- Leverage `hyper` or `reqwest` for async HTTP requests.
61- Use `serde` for serialization/deserialization.
62- Use `sqlx` or `tokio-postgres` for async database interactions.
63- Utilize `tonic` for gRPC with async support.
64 
65Refer to Rust's async book and `tokio` documentation for in-depth information on async patterns, best practices, and advanced features.