Rudi

Rudi - an out-of-the-box dependency injection framework for Rust.

use rudi::{Context, Singleton, Transient};

// Register `fn(cx) -> A { A }` as the constructor for `A`
#[derive(Debug)]
#[Transient]
struct A;

#[derive(Debug)]
struct B(A);

// Register `fn(cx) -> B { B::new(cx.resolve::<A>()) }` as the constructor for `B`
#[Transient]
impl B {
    fn new(a: A) -> B {
        B(a)
    }
}

// Register `fn(cx) -> C { C::B(cx.resolve::<B>()) }` as the constructor for `C`
#[allow(dead_code)]
#[Transient]
enum C {
    A(A),

    #[di]
    B(B),
}

// Register `fn(cx) -> () { Run(cx.resolve::<B>(), cx.resolve::<C>()) }` as the constructor for `()`
#[Singleton]
fn Run(b: B, c: C) {
    println!("{:?}", b);
    assert!(matches!(c, C::B(_)));
}

fn main() {
    // Automatically register all types and functions with the `#[Singleton]` or `#[Transient]` attribute.
    let mut cx = Context::auto_register();

    // Get an instance of `()` from the `Context`, which will call the `Run` function.
    // This is equivalent to `cx.resolve::<()>();`
    cx.resolve()
}

Features

• Two lifetimes: singleton and transient.
• Async functions and async constructors.
• Attribute macros can be used on struct, enum, impl block and function.
• Manual and automatic registration (thanks to inventory).
• Easy binding of trait implementations and trait objects.
• Distinguishing different instances with types and names.
• Generics (but must be monomorphized and manually registered) (example).
• Conditional registration (example).
• References (but only singleton lifetime) (example).

More complex example

use std::{fmt::Debug, rc::Rc};

use rudi::{Context, Singleton, Transient};

// Register `async fn(cx) -> i32 { 42 }` as the constructor for `i32`,
// and specify the name of the instance of this `i32` type as `"number"`.
#[Singleton(name = "number")]
async fn Number() -> i32 {
    42
}

// Register `async fn(cx) -> Foo { Foo { number: cx.resolve_with_name_async("number").await } }`
// as the constructor for `Foo`, and specify the name of the instance of this `Foo` type as `"foo"`.
#[derive(Debug, Clone)]
#[Singleton(async, name = "foo")]
struct Foo {
    #[di(name = "number")]
    number: i32,
}

#[derive(Debug)]
struct Bar(Foo);

impl Bar {
    fn into_debug(self) -> Rc<dyn Debug> {
        Rc::new(self)
    }
}

// Register `async fn(cx) -> Bar { Bar::new(cx.resolve_with_name_async("foo").await).await }`
// as the constructor for `Bar`.
//
// Bind the implementation of the `Debug` trait and the trait object of the `Debug` trait,
// it will register `asycn fn(cx) -> Rc<dyn Debug> { Bar::into_debug(cx.resolve_async().await) }`
// as the constructor for `Rc<dyn Debug>`.
#[Transient(binds = [Self::into_debug])]
impl Bar {
    async fn new(#[di(name = "foo")] f: Foo) -> Bar {
        Bar(f)
    }
}

#[Singleton]
async fn Run(bar: Bar, debug: Rc<dyn Debug>, #[di(name = "foo")] f: Foo) {
    println!("{:?}", bar);
    assert_eq!(format!("{:?}", bar), format!("{:?}", debug));
    assert_eq!(format!("{:?}", bar.0.number), format!("{:?}", f.number));
}

#[tokio::main]
async fn main() {
    let mut cx = Context::auto_register();

    cx.resolve_async().await
}

More examples can be found in the examples and tests directories.

Credits

• Koin: This project's API design and test cases were inspired by Koin.
• inventory: This project uses inventory to implement automatic registration, making Rust's automatic registration very simple.

Contributing

Thanks for your help improving the project! We are so happy to have you!

License

Licensed under either of

• Apache License, Version 2.0,(LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT) at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.