pub struct Steer<S, F, Req> { /* private fields */ }
Available on crate feature steer only.
Expand description

Steer manages a list of Services which all handle the same type of request.

An example use case is a sharded service. It accepts new requests, then:

  1. Determines, via the provided Picker, which Service the request coresponds to.
  2. Waits (in Service::poll_ready) for all services to be ready.
  3. Calls the correct Service with the request, and returns a future corresponding to the call.

Note that Steer must wait for all services to be ready since it can’t know ahead of time which Service the next message will arrive for, and is unwilling to buffer items indefinitely. This will cause head-of-line blocking unless paired with a Service that does buffer items indefinitely, and thus always returns Poll::Ready. For example, wrapping each component service with a Buffer with a high enough limit (the maximum number of concurrent requests) will prevent head-of-line blocking in Steer.

Implementations

Make a new Steer with a list of Service’s and a Picker.

Note: the order of the Service’s is significant for Picker::pick’s return value.

Trait Implementations

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Responses given by the service.

Errors produced by the service.

The future response value.

Returns Poll::Ready(Ok(())) when the service is able to process requests. Read more

Process the request and return the response asynchronously. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more

Instruments this type with the current Span, returning an Instrumented wrapper. Read more

Calls U::from(self).

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

Available on crate feature util only.

Yields a mutable reference to the service when it is ready to accept a request.

👎 Deprecated since 0.4.6:

please use the ServiceExt::ready method instead

Available on crate feature util only.

Yields a mutable reference to the service when it is ready to accept a request.

Available on crate feature util only.

Yields the service when it is ready to accept a request.

Available on crate feature util only.

Consume this Service, calling with the providing request once it is ready.

Available on crate feature util only.

Process all requests from the given Stream, and produce a Stream of their responses. Read more

Available on crate feature util only.

Executes a new future after this service’s future resolves. This does not alter the behaviour of the poll_ready method. Read more

Available on crate feature util only.

Maps this service’s response value to a different value. This does not alter the behaviour of the poll_ready method. Read more

Available on crate feature util only.

Maps this service’s error value to a different value. This does not alter the behaviour of the poll_ready method. Read more

Available on crate feature util only.

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

Available on crate feature util only.

Composes a function in front of the service. Read more

Available on crate features util and filter only.

Composes this service with a Filter that conditionally accepts or rejects requests based on a predicate. Read more

Available on crate features util and filter only.

Composes this service with an AsyncFilter that conditionally accepts or rejects requests based on an [async predicate]. Read more

Available on crate feature util only.

Composes an asynchronous function after this service. Read more

Available on crate feature util only.

Composes a function that transforms futures produced by the service. Read more

Available on crate feature util only.

Convert the service into a Service + Send trait object. Read more

Available on crate feature util only.

Convert the service into a Service + Clone + Send trait object. Read more

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

Uses borrowed data to replace owned data, usually by cloning. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

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

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