Struct tower::util::BoxLayer[−][src]

pub struct BoxLayer<In, T, U, E> { /* fields omitted */ }

This is supported on crate feature util only.

A boxed Layer trait object.

BoxLayer turns a layer into a trait object, allowing both the Layer itself and the output Service to be dynamic, while having consistent types.

This Layer produces BoxService instances erasing the type of the Service produced by the wrapped Layer.

Example

BoxLayer can, for example, be useful to create layers dynamically that otherwise wouldn’t have the same types. In this example, we include a Timeout layer only if an environment variable is set. We can use BoxLayer to return a consistent type regardless of runtime configuration:

use std::time::Duration;
use tower::{Service, ServiceBuilder, BoxError, util::BoxLayer};

fn common_layer<S, T>() -> BoxLayer<S, T, S::Response, BoxError>
where
    S: Service<T> + Send + 'static,
    S::Future: Send + 'static,
    S::Error: Into<BoxError> + 'static,
{
    let builder = ServiceBuilder::new()
        .concurrency_limit(100);

    if std::env::var("SET_TIMEOUT").is_ok() {
        let layer = builder
            .timeout(Duration::from_secs(30))
            .into_inner();

        BoxLayer::new(layer)
    } else {
        let layer = builder
            .map_err(Into::into)
            .into_inner();

        BoxLayer::new(layer)
    }
}

Implementations

`impl<In, T, U, E> BoxLayer<In, T, U, E>`[src]

`pub fn new<L>(inner_layer: L) -> Self where L: Layer<In> + Send + Sync + 'static, L::Service: Service<T, Response = U, Error = E> + Send + 'static, <L::Service as Service<T>>::Future: Send + 'static,` [src]

Create a new BoxLayer.

Trait Implementations

`impl<In, T, U, E> Clone for BoxLayer<In, T, U, E>`[src]

`fn clone(&self) -> Self`[src]

`pub fn clone_from(&mut self, source: &Self)`1.0.0 [src]

`impl<In, T, U, E> Debug for BoxLayer<In, T, U, E>`[src]

`fn fmt(&self, fmt: &mut Formatter<'_>) -> Result`[src]

`impl<In, T, U, E> Layer<In> for BoxLayer<In, T, U, E>`[src]

`type Service = BoxService<T, U, E>`

The wrapped service

`fn layer(&self, inner: In) -> Self::Service`[src]

Auto Trait Implementations

`impl<In, T, U, E> !RefUnwindSafe for BoxLayer<In, T, U, E>`

`impl<In, T, U, E> Send for BoxLayer<In, T, U, E>`

`impl<In, T, U, E> Sync for BoxLayer<In, T, U, E>`

`impl<In, T, U, E> Unpin for BoxLayer<In, T, U, E>`

`impl<In, T, U, E> !UnwindSafe for BoxLayer<In, T, U, E>`

Blanket Implementations

`impl<T> Any for T where T: 'static + ?Sized,` [src]

`pub fn type_id(&self) -> TypeId`[src]

`impl<T> Borrow<T> for T where T: ?Sized,` [src]

`pub fn borrow(&self) -> &T`[src]

`impl<T> BorrowMut<T> for T where T: ?Sized,` [src]

`pub fn borrow_mut(&mut self) -> &mut T`[src]

`impl<T> From<T> for T`[src]

`pub fn from(t: T) -> T`[src]

`impl<T> Instrument for T`[src]

`pub fn instrument(self, span: Span) -> Instrumented<Self>`[src]

`pub fn in_current_span(self) -> Instrumented<Self>`[src]

`impl<T, U> Into for T where U: From<T>,` [src]

`pub fn into(self) -> U`[src]

`impl<T> ToOwned for T where T: Clone,` [src]

`type Owned = T`

The resulting type after obtaining ownership.

`pub fn to_owned(&self) -> T`[src]

`pub fn clone_into(&self, target: &mut T)`[src]

`impl<T, U> TryFrom for T where U: Into<T>,` [src]

`type Error = Infallible`

The type returned in the event of a conversion error.

`pub fn try_from(value: U) -> Result<T, <T as TryFrom>::Error>`[src]

`impl<T, U> TryInto for T where U: TryFrom<T>,` [src]

`type Error = >::Error`

The type returned in the event of a conversion error.

Struct tower::util::BoxLayer⎘[−][src]

Example

Implementations

impl<In, T, U, E> BoxLayer<In, T, U, E>[src]

pub fn new<L>(inner_layer: L) -> Self where L: Layer<In> + Send + Sync + 'static, L::Service: Service<T, Response = U, Error = E> + Send + 'static, <L::Service as Service<T>>::Future: Send + 'static, [src]

Trait Implementations

impl<In, T, U, E> Clone for BoxLayer<In, T, U, E>[src]

fn clone(&self) -> Self[src]

pub fn clone_from(&mut self, source: &Self)1.0.0[src]

impl<In, T, U, E> Debug for BoxLayer<In, T, U, E>[src]

fn fmt(&self, fmt: &mut Formatter<'_>) -> Result[src]

impl<In, T, U, E> Layer<In> for BoxLayer<In, T, U, E>[src]

type Service = BoxService<T, U, E>

fn layer(&self, inner: In) -> Self::Service[src]

Auto Trait Implementations

impl<In, T, U, E> !RefUnwindSafe for BoxLayer<In, T, U, E>

impl<In, T, U, E> Send for BoxLayer<In, T, U, E>

impl<In, T, U, E> Sync for BoxLayer<In, T, U, E>

impl<In, T, U, E> Unpin for BoxLayer<In, T, U, E>

impl<In, T, U, E> !UnwindSafe for BoxLayer<In, T, U, E>

Blanket Implementations

impl<T> Any for T where T: 'static + ?Sized, [src]

pub fn type_id(&self) -> TypeId[src]

impl<T> Borrow<T> for T where T: ?Sized, [src]

pub fn borrow(&self) -> &T[src]

impl<T> BorrowMut<T> for T where T: ?Sized, [src]

pub fn borrow_mut(&mut self) -> &mut T[src]

impl<T> From<T> for T[src]

pub fn from(t: T) -> T[src]

impl<T> Instrument for T[src]

pub fn instrument(self, span: Span) -> Instrumented<Self>[src]

pub fn in_current_span(self) -> Instrumented<Self>[src]

impl<T, U> Into<U> for T where U: From<T>, [src]

pub fn into(self) -> U[src]

impl<T> ToOwned for T where T: Clone, [src]

type Owned = T

pub fn to_owned(&self) -> T[src]

pub fn clone_into(&self, target: &mut T)[src]

impl<T, U> TryFrom<U> for T where U: Into<T>, [src]

type Error = Infallible

pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>[src]

impl<T, U> TryInto<U> for T where U: TryFrom<T>, [src]

type Error = <U as TryFrom<T>>::Error

pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>[src]

impl<V, T> VZip<V> for T where V: MultiLane<T>,

pub fn vzip(self) -> V