A core Order Management System (OMS) built in Rust, designed as a learning project to explore low-latency design patterns, concurrency, and backend development in Rust. This system handles order creation, modification, cancellation, and matching with an in-memory order book and SQLite persistence.

REST API: For order operations (creation, modification, cancellation) built with Axum.

In-Memory Order Book: Manages buy and sell orders using VecDeque.

FIFO Matching Engine: Matches orders based on first-in, first-out logic for orders at the same price level (current implementation prioritizes orders as they arrive on each side).

Concurrent Processing Foundation: Utilizes Tokio for asynchronous request handling and Arc<Mutex<>> for thread-safe access to the order book and database connection.

Order Persistence: Uses SQLite via rusqlite to save and load order states across server restarts. All order actions (create, modify, cancel, match) are persisted.

Unit Tests: Includes tests for core order book logic (add, match, modify, cancel).

Logging: Uses the tracing library for application logging.

Rust: Core programming language.

Tokio: Asynchronous runtime for concurrent operations.

Axum: Web framework for building the REST API.

Serde: For JSON serialization and deserialization.

Rusqlite: SQLite wrapper for database interaction (with bundled feature).

Tracing: For application logging and diagnostics.

To start the OMS server: