Trait Service 

pub trait Service<In>: Send + Sync {
    type Out;

    // Required method
    fn execute(&self, input: In) -> impl Future<Output = Self::Out> + Send;
}

An async function In → Out that processes inputs.

This trait is the foundation for building composable services. Implement it directly for custom services, or use Execute to wrap closures.

See the crate documentation for usage examples and layer composition.

Required Associated Types

type Out

The output type returned by this service.

Required Methods

fn execute(&self, input: In) -> impl Future<Output = Self::Out> + Send

Processes the input and returns the output.

The returned future must be Send for compatibility with multi-threaded async runtimes.

Examples

use layered::Service;

struct EchoService;

impl Service<String> for EchoService {
    type Out = String;

    async fn execute(&self, input: String) -> Self::Out {
        input
    }
}

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl<S, In> Service<In> for Box<S>

where S: Service<In>,

type Out = <S as Service<In>>::Out

fn execute(&self, input: In) -> impl Future<Output = Self::Out> + Send

impl<S, In> Service<In> for Arc<S>

where S: Service<In>,

type Out = <S as Service<In>>::Out

fn execute(&self, input: In) -> impl Future<Output = Self::Out> + Send

Implementors

impl<E, F, In, Out> Service<In> for Execute<E>

where E: Fn(In) -> F + Send + Sync, F: Future<Output = Out> + Send,

type Out = Out

impl<In: Send, Out, S> Service<In> for Intercept<In, Out, S>

where S: Service<In, Out = Out>,

Available on crate features intercept only.

type Out = Out

impl<In: Send, Out: Send> Service<In> for DynamicService<In, Out>

Available on crate features dynamic-service only.

type Out = Out

impl<S, In: Send> Service<In> for Adapter<S>

where S: Service<In> + Send + Sync + Clone, S::Future: Send,

Available on crate features tower-service only.

type Out = Result<<S as Service<In>>::Response, <S as Service<In>>::Error>