supply-demand

A flexible, async-ready dependency injection and supply/demand orchestration library for Rust. Inspired by IoC/DI patterns, supports runtime-typed supplier registries and dynamic dependency graphs.

Features

• Register arbitrary async/sync suppliers by type key
• Type-erased registry for heterogeneous dependencies
• Local override and dynamic graph composition
• async_trait support for ergonomic async/await suppliers

Example

use supply_demand::{Supplier, ErasedSupplier, Demand, Scope, SupplierRegistry};
use async_trait::async_trait;
use std::collections::HashMap;
use std::sync::Arc;

// A supplier returning i32
struct ValueASupplier;

#[async_trait]
impl Supplier for ValueASupplier {
    type Input = ();
    type Output = i32;

    async fn supply(&self, _input: (), _scope: Arc<Scope>) -> i32 {
        42
    }
}

#[tokio::main]
async fn main() {
    let mut registry: SupplierRegistry = HashMap::new();
    registry.insert("valueA".to_string(), Arc::new(ValueASupplier));

    let scope = Arc::new(Scope {
        registry: Arc::new(registry),
    });

    let demand = Demand { type_: "valueA".to_string(), override_suppliers: None };
    let result: i32 = scope.demand(demand, Box::new(())).await;

    println!("Result is {}", result); // prints "Result is 42"
}

Documentation

See full documentation at docs.rs/supply-demand.

License

Licensed under MIT license.