async fn(Request) -> Result
Filter::check and AsyncFilter::check methods which check a
request against the filter's Predicate (#521)get_ref, get_mut, and into_inner methods to Filter
and AsyncFilter, allowing access to the wrapped service (#522)layer associated function to AndThen, Then,
MapRequest, MapResponse, and MapResult types. These return a Layer
that produces middleware of that type, as a convenience to avoid having to
import the Layer type separately. (#524)Clone impls to AndThenLayer, MapRequestLayer,
and MapErrLayer, when the mapped function implements Clone (#525)FutureService::new constructor, with less restrictive bounds
than the future_service free function (#523)This is a major breaking release including a large number of changes. In
particular, this release updates tower to depend on Tokio 1.0, and moves all
middleware into the tower crate. In addition, Tower 0.4 reworks several
middleware APIs, as well as introducing new ones.
This release does not change the core Service or Layer traits, so tower
0.4 still depends on tower-service 0.3 and tower-layer 0.3. This means that
tower 0.4 is still compatible with libraries that depend on those crates.
MakeService::into_service and MakeService::as_service for
converting MakeServices into Services (#492)steer middleware for routing requests to one of a set of
services (#426)MapRequest middleware and ServiceExt::map_request, for
applying a function to a request before passing it to the inner service
(#435)MapResponse middleware and ServiceExt::map_response, for
applying a function to the Response type of an inner service after its
future completes (#435)MapErr middleware and ServiceExt::map_err, for
applying a function to the Error returned by an inner service if it fails
(#396)MapResult middleware and ServiceExt::map_result, for
applying a function to the Result returned by an inner service's future
regardless of whether it succeeds or fails (#499)Then middleware and ServiceExt::then, for chaining another
future after an inner service's future completes (with a Response or an
Error) (#500)AndThen middleware and ServiceExt::and_then, for
chaining another future after an inner service's future completes successfully
(#485)layer_fn, for constructing a Layer from a function taking
a Service and returning a different Service (#491)FutureService, which implements Service for a
Future whose Output type is a Service ([#496])BoxService::layer and UnsyncBoxService::layer, to make
constructing layers more ergonomic (#503)Layer impl for &Layer (#446)Retry::get_ref, Retry::get_mut, and Retry::into_inner
to access the inner service (#463)Timeout::get_ref, Timeout::get_mut, and
Timeout::into_inner to access the inner service (#463)Clone and Copy impls for BufferLayer (#493)tower-* crates were merged into tower and placed
behind feature flags (#432)ServiceBuilder::service take self by reference rather
than by value (#504)MakeService in the response future, rather than
in poll_ready, allowing the reconnect service to be reused when a reconnect
fails (#386, #437)Discover to be a sealed trait alias for a
TryStream<Item = Change>. Discover implementations are now written by
implementing Stream. (#443)Instrument trait to TrackCompletion (#445)NoInstrument to CompleteOnResponse (#445)BalanceLayer to MakeBalanceLayer (#449)BalanceMake to MakeBalance (#449)ready_cache::error::Failed's fmt::Debug impl to
require the key type to also implement fmt::Debug (#467)Filter and Predicate to use a synchronous function as
a predicate (#508)Filter and Predicate (where Predicates
returned a Future) to AsyncFilter and AsyncPredicate (#508)Predicates now take a Request type by value and may return a
new request, potentially of a different type (#508)Predicates may now return an error of any type (#508)RateLimit services do not reset the remaining
count when rate limiting (#438, [#439])oneshot futures panic if the service does not
immediately become ready (#447)ready_cache::error::Failed not returning inner error types
via Error::source (#467)buffer where buffer slots were
eagerly reserved for hedge requests even if they were not sent (#472)