95 lines
2.6 KiB
Rust
95 lines
2.6 KiB
Rust
//! # Tower service discovery
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//!
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//! Service discovery is the automatic detection of services available to the
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//! consumer. These services typically live on other servers and are accessible
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//! via the network; however, it is possible to discover services available in
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//! other processes or even in process.
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mod error;
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mod list;
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mod stream;
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pub use self::{list::ServiceList, stream::ServiceStream};
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use std::hash::Hash;
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use std::ops;
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use std::{
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pin::Pin,
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task::{Context, Poll},
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};
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/// Provide a uniform set of services able to satisfy a request.
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///
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/// This set of services may be updated over time. On each change to the set, a
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/// new `NewServiceSet` is yielded by `Discover`.
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///
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/// See crate documentation for more details.
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pub trait Discover {
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/// NewService key
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type Key: Hash + Eq;
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/// The type of `Service` yielded by this `Discover`.
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type Service;
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/// Error produced during discovery
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type Error;
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/// Yields the next discovery change set.
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fn poll_discover(
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self: Pin<&mut Self>,
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cx: &mut Context<'_>,
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) -> Poll<Result<Change<Self::Key, Self::Service>, Self::Error>>;
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}
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// delegate through Pin
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impl<P> Discover for Pin<P>
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where
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P: Unpin + ops::DerefMut,
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P::Target: Discover,
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{
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type Key = <<P as ops::Deref>::Target as Discover>::Key;
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type Service = <<P as ops::Deref>::Target as Discover>::Service;
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type Error = <<P as ops::Deref>::Target as Discover>::Error;
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fn poll_discover(
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self: Pin<&mut Self>,
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cx: &mut Context<'_>,
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) -> Poll<Result<Change<Self::Key, Self::Service>, Self::Error>> {
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Pin::get_mut(self).as_mut().poll_discover(cx)
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}
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}
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impl<D: ?Sized + Discover + Unpin> Discover for &mut D {
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type Key = D::Key;
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type Service = D::Service;
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type Error = D::Error;
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fn poll_discover(
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mut self: Pin<&mut Self>,
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cx: &mut Context<'_>,
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) -> Poll<Result<Change<Self::Key, Self::Service>, Self::Error>> {
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Discover::poll_discover(Pin::new(&mut **self), cx)
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}
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}
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impl<D: ?Sized + Discover + Unpin> Discover for Box<D> {
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type Key = D::Key;
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type Service = D::Service;
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type Error = D::Error;
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fn poll_discover(
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mut self: Pin<&mut Self>,
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cx: &mut Context<'_>,
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) -> Poll<Result<Change<Self::Key, Self::Service>, Self::Error>> {
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D::poll_discover(Pin::new(&mut *self), cx)
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}
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}
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/// A change in the service set
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#[derive(Debug)]
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pub enum Change<K, V> {
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/// A new service identified by key `K` was identified.
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Insert(K, V),
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/// The service identified by key `K` disappeared.
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Remove(K),
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}
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