🐚 Shellder

A lightweight, Spring-inspired Dependency Injection framework for Rust.

A Crab needs its Shell.

✨ Overview

Shellder provides a minimal, ergonomic foundation for building modular Rust applications with Dependency Injection and lifecycle management.

The core design focuses on:

• Type-based registration and resolution
• Lazy or eager singleton initialization
• Thread-safe storage with Arc
• Simple, predictable API
• Ergonomic procedural macros

This crate is ideal for applications and services where you want to decouple components and manage lifecycles explicitly.

🚀 Quick Start

Add Shellder to your Cargo.toml:

[dependencies]
shellder = "0.2.0"

Example usage:

use shellder::{component, Hooks, DEFAULT_CONTAINER};

#[component]
#[derive(Hooks)]
pub struct MyService;

fn main() {
    MyService::register(&*DEFAULT_CONTAINER);
    MyService::run();
}

🧩 Current Features

✅ Type-based registration and resolution ✅ Eager singleton registration ✅ Lazy initialization (factories run on first resolve) ✅ Thread-safe interior mutability ✅ #[component] macro to auto-register components ✅ #[derive(Hooks)] for default lifecycle behavior ✅ Minimal dependencies (once_cell, thiserror, syn, quote)

🛣️ Roadmap / Upcoming Features

Below are planned improvements:

• Named Registration & Resolution

  • Map components with string keys

  • Enable multiple instances of the same type

• Configuration Management

  • Load .toml / .yaml configs into typed structs automatically

• Container Builder

  • Fluent API for building and wiring dependencies

• Advanced Lifecycle Hooks

  • start() and stop() methods for components to manage initialization and cleanup

• Procedural Macros

  -#[inject] derive macros to reduce boilerplate

  • Attribute macros for custom lifecycles

• Application Runner

  • shellder::run() helper for simple startup and shutdown orchestration

• Testing Utilities

  • Helpers to swap dependencies with mocks for unit testing

💡 Vision

Shellder aims to be a batteries-included application framework inspired by Spring, but fully Rust-idiomatic:

• Clear compile-time safety

• Minimal runtime overhead

• Ergonomic macros and configuration

• Easy integration with web frameworks and CLI tools

📝 License

Licensed under Apache-2.0.

🤝 Contributing

Contributions, ideas, and feedback are very welcome! Please open an issue or pull request.

📣 Stay Tuned

Follow the project for upcoming releases with configuration loading, lifecycle management, and expanded macro support.