Shaku

Shaku is a compile time dependency injection Rust library. See the docs for more details, including a getting started guide.

Guides

• General getting started guide, with components (aka singletons)
• Providers (aka transient)
• Submodules

Example

use shaku::{module, Component, Interface, HasComponent};
use std::sync::Arc;

trait Logger: Interface {
    fn log(&self, content: &str);
}

trait DateLogger: Interface {
    fn log_date(&self);
}

#[derive(Component)]
#[shaku(interface = Logger)]
struct LoggerImpl;

impl Logger for LoggerImpl {
    fn log(&self, content: &str) {
        println!("{}", content);
    }
}

#[derive(Component)]
#[shaku(interface = DateLogger)]
struct DateLoggerImpl {
    #[shaku(inject)]
    logger: Arc<dyn Logger>,
    today: String,
    year: usize,
}

impl DateLogger for DateLoggerImpl {
    fn log_date(&self) {
        self.logger.log(&format!("Today is {}, {}", self.today, self.year));
    }
}

module! {
    MyModule {
        components = [LoggerImpl, DateLoggerImpl],
        providers = []
    }
}

fn main() {
    let module = MyModule::builder()
        .with_component_parameters::<DateLoggerImpl>(DateLoggerImplParameters {
            today: "Jan 26".to_string(),
            year: 2020
        })
        .build();

    let date_logger: &dyn DateLogger = module.resolve_ref();
    date_logger.log_date();
}

Component vs Provider

Component represents a single instance of a service, aka a singleton. Provider is more like a factory for instances. Each time a component is resolved you will get the same instance. Each time a provider is resolved you will get a new instance.

For more details on Component and Provider, see the getting started guide and the provider getting started guide.

Minimum Supported Rust Version

Shaku supports the latest stable release of Rust, plus the previous two versions at minimum (but possibly more). Changes to the minimum supported version will be noted in the changelog.

Minimum supported version: 1.38.0

Project Status

The foundation of shaku's API is in place, and now the focus is to mature the project based on user feedback. I (@AzureMarker) am active in the project, but I do not have many major changes of my own planned for the future. Most of the future changes will be based on user feedback.

Acknowledgements

This library started off as "he_di" (later renamed to "shaku") under the guidance of @bgbahoue and @U007D. Their work inspired the current maintainer (@AzureMarker) to continue the library from where they left off.