Struct tower::buffer::Buffer

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pub struct Buffer<T, Request>
where T: Service<Request>,
{ /* private fields */ }
Expand description

Adds an mpsc buffer in front of an inner service.

See the module documentation for more details.

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impl<T, Request> Buffer<T, Request>
where T: Service<Request>, T::Error: Into<BoxError>,

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pub fn new(service: T, bound: usize) -> Self
where T: Send + 'static, T::Future: Send, T::Error: Send + Sync, Request: Send + 'static,

Creates a new Buffer wrapping service.

bound gives the maximal number of requests that can be queued for the service before backpressure is applied to callers.

The default Tokio executor is used to run the given service, which means that this method must be called while on the Tokio runtime.

§A note on choosing a bound

When Buffer’s implementation of poll_ready returns Poll::Ready, it reserves a slot in the channel for the forthcoming call. However, if this call doesn’t arrive, this reserved slot may be held up for a long time. As a result, it’s advisable to set bound to be at least the maximum number of concurrent requests the Buffer will see. If you do not, all the slots in the buffer may be held up by futures that have just called poll_ready but will not issue a call, which prevents other senders from issuing new requests.

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pub fn pair( service: T, bound: usize, ) -> (Buffer<T, Request>, Worker<T, Request>)
where T: Send + 'static, T::Error: Send + Sync, Request: Send + 'static,

Creates a new Buffer wrapping service, but returns the background worker.

This is useful if you do not want to spawn directly onto the tokio runtime but instead want to use your own executor. This will return the Buffer and the background Worker that you can then spawn.

Trait Implementations§

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impl<T, Request> Clone for Buffer<T, Request>
where T: Service<Request>,

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fn clone(&self) -> Self

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<T, Request: Debug> Debug for Buffer<T, Request>
where T: Service<Request> + Debug, T::Future: Debug,

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

Formats the value using the given formatter. Read more
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impl<T, Request> Service<Request> for Buffer<T, Request>
where T: Service<Request>, T::Error: Into<BoxError>,

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type Response = <T as Service<Request>>::Response

Responses given by the service.
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type Error = Box<dyn Error + Sync + Send>

Errors produced by the service.
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type Future = ResponseFuture<<T as Service<Request>>::Future>

The future response value.
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fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>>

Returns Poll::Ready(Ok(())) when the service is able to process requests. Read more
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fn call(&mut self, request: Request) -> Self::Future

Process the request and return the response asynchronously. Read more

Auto Trait Implementations§

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impl<T, Request> Freeze for Buffer<T, Request>

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impl<T, Request> !RefUnwindSafe for Buffer<T, Request>

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impl<T, Request> Send for Buffer<T, Request>
where Request: Send, <T as Service<Request>>::Future: Send,

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impl<T, Request> Sync for Buffer<T, Request>
where Request: Send, <T as Service<Request>>::Future: Send,

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impl<T, Request> Unpin for Buffer<T, Request>

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impl<T, Request> !UnwindSafe for Buffer<T, Request>

Blanket Implementations§

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

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> CloneToUninit for T
where T: Clone,

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default unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (clone_to_uninit)
Performs copy-assignment from self to dst. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<M, S, Target, Request> MakeService<Target, Request> for M
where M: Service<Target, Response = S>, S: Service<Request>,

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type Response = <S as Service<Request>>::Response

Responses given by the service
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type Error = <S as Service<Request>>::Error

Errors produced by the service
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type Service = S

The Service value created by this factory
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type MakeError = <M as Service<Target>>::Error

Errors produced while building a service.
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type Future = <M as Service<Target>>::Future

The future of the Service instance.
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fn poll_ready( &mut self, cx: &mut Context<'_>, ) -> Poll<Result<(), <M as MakeService<Target, Request>>::MakeError>>

Returns Poll::Ready when the factory is able to create more services. Read more
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fn make_service( &mut self, target: Target, ) -> <M as MakeService<Target, Request>>::Future

Create and return a new service value asynchronously.
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fn into_service(self) -> IntoService<Self, Request>
where Self: Sized,

Consume this MakeService and convert it into a Service. Read more
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fn as_service(&mut self) -> AsService<'_, Self, Request>
where Self: Sized,

Convert this MakeService into a Service without consuming the original MakeService. Read more
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impl<T, Request> ServiceExt<Request> for T
where T: Service<Request> + ?Sized,

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fn ready(&mut self) -> Ready<'_, Self, Request>
where Self: Sized,

Yields a mutable reference to the service when it is ready to accept a request.
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fn ready_and(&mut self) -> ReadyAnd<'_, Self, Request>
where Self: Sized,

👎Deprecated since 0.4.6: please use the ServiceExt::ready method instead
Yields a mutable reference to the service when it is ready to accept a request.
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fn ready_oneshot(self) -> ReadyOneshot<Self, Request>
where Self: Sized,

Yields the service when it is ready to accept a request.
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fn oneshot(self, req: Request) -> Oneshot<Self, Request>
where Self: Sized,

Consume this Service, calling with the providing request once it is ready.
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fn call_all<S>(self, reqs: S) -> CallAll<Self, S>
where Self: Sized, Self::Error: Into<BoxError>, S: Stream<Item = Request>,

Process all requests from the given Stream, and produce a Stream of their responses. Read more
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fn and_then<F>(self, f: F) -> AndThen<Self, F>
where Self: Sized, F: Clone,

Executes a new future after this service’s future resolves. This does not alter the behaviour of the poll_ready method. Read more
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fn map_response<F, Response>(self, f: F) -> MapResponse<Self, F>
where Self: Sized, F: FnOnce(Self::Response) -> Response + Clone,

Maps this service’s response value to a different value. This does not alter the behaviour of the poll_ready method. Read more
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fn map_err<F, Error>(self, f: F) -> MapErr<Self, F>
where Self: Sized, F: FnOnce(Self::Error) -> Error + Clone,

Maps this service’s error value to a different value. This does not alter the behaviour of the poll_ready method. Read more
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fn map_result<F, Response, Error>(self, f: F) -> MapResult<Self, F>
where Self: Sized, Error: From<Self::Error>, F: FnOnce(Result<Self::Response, Self::Error>) -> Result<Response, Error> + Clone,

Maps this service’s result type (Result<Self::Response, Self::Error>) to a different value, regardless of whether the future succeeds or fails. Read more
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fn map_request<F, NewRequest>(self, f: F) -> MapRequest<Self, F>
where Self: Sized, F: FnMut(NewRequest) -> Request,

Composes a function in front of the service. Read more
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fn filter<F, NewRequest>(self, filter: F) -> Filter<Self, F>
where Self: Sized, F: Predicate<NewRequest>,

Composes this service with a Filter that conditionally accepts or rejects requests based on a predicate. Read more
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fn filter_async<F, NewRequest>(self, filter: F) -> AsyncFilter<Self, F>
where Self: Sized, F: AsyncPredicate<NewRequest>,

Composes this service with an AsyncFilter that conditionally accepts or rejects requests based on an [async predicate]. Read more
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fn then<F, Response, Error, Fut>(self, f: F) -> Then<Self, F>
where Self: Sized, Error: From<Self::Error>, F: FnOnce(Result<Self::Response, Self::Error>) -> Fut + Clone, Fut: Future<Output = Result<Response, Error>>,

Composes an asynchronous function after this service. Read more
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fn map_future<F, Fut, Response, Error>(self, f: F) -> MapFuture<Self, F>
where Self: Sized, F: FnMut(Self::Future) -> Fut, Error: From<Self::Error>, Fut: Future<Output = Result<Response, Error>>,

Composes a function that transforms futures produced by the service. Read more
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fn boxed(self) -> BoxService<Request, Self::Response, Self::Error>
where Self: Sized + Send + 'static, Self::Future: Send + 'static,

Convert the service into a Service + Send trait object. Read more
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fn boxed_clone(self) -> BoxCloneService<Request, Self::Response, Self::Error>
where Self: Clone + Sized + Send + 'static, Self::Future: Send + 'static,

Convert the service into a Service + Clone + Send trait object. Read more
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impl<T> ToOwned for T
where T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V

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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more