Refactor control::destination::background::client module (#38)

This branch should not make any functional changes.

This branch makes two minor refactorings to the `client` module in 
`control::destination::background`:

 1. Remove the `AddOrigin` middleware and replace it with the 
    `tower-add-origin` crate from `tower-http`. These middlewares are
    functionally identical, but the Tower version has tests.
 2. Change `ClientService` from a type alias to a tuple struct. This
    means that some of the middleware that are used only in this module
    (`LogErrors` and `Backoff`) are no longer part of a publicly visible
    type and can be made private to the module.

Signed-off-by: Eliza Weisman <eliza@buoyant.io>

Cargo.lock

@@ -506,6 +506,7 @@ dependencies = [
  "tokio-rustls 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-signal 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-timer 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tower-add-origin 0.1.0 (git+https://github.com/tower-rs/tower-http)",
  "tower-balance 0.1.0 (git+https://github.com/tower-rs/tower)",
  "tower-buffer 0.1.0 (git+https://github.com/tower-rs/tower)",
  "tower-discover 0.1.0 (git+https://github.com/tower-rs/tower)",
@@ -1218,6 +1219,16 @@ dependencies = [
  "tokio-reactor 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "tower-add-origin"
+version = "0.1.0"
+source = "git+https://github.com/tower-rs/tower-http#c9e13f641a681b3ef01e96910789586e39aee2e2"
+dependencies = [
+ "futures 0.1.21 (registry+https://github.com/rust-lang/crates.io-index)",
+ "http 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tower-service 0.1.0 (git+https://github.com/tower-rs/tower)",
+]
+
 [[package]]
 name = "tower-balance"
 version = "0.1.0"
@@ -1679,6 +1690,7 @@ dependencies = [
 "checksum tokio-threadpool 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "b3c3873a6d8d0b636e024e77b9a82eaab6739578a06189ecd0e731c7308fbc5d"
 "checksum tokio-timer 0.2.4 (registry+https://github.com/rust-lang/crates.io-index)" = "028b94314065b90f026a21826cffd62a4e40a92cda3e5c069cc7b02e5945f5e9"
 "checksum tokio-udp 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "137bda266504893ac4774e0ec4c2108f7ccdbcb7ac8dced6305fe9e4e0b5041a"
+"checksum tower-add-origin 0.1.0 (git+https://github.com/tower-rs/tower-http)" = "<none>"
 "checksum tower-balance 0.1.0 (git+https://github.com/tower-rs/tower)" = "<none>"
 "checksum tower-buffer 0.1.0 (git+https://github.com/tower-rs/tower)" = "<none>"
 "checksum tower-discover 0.1.0 (git+https://github.com/tower-rs/tower)" = "<none>"

Cargo.toml

@@ -47,6 +47,7 @@ tokio = "0.1.7"
 tokio-signal = "0.2"
 tokio-timer = "0.2.4"   # for tokio_timer::clock
 tokio-connect         = { git = "https://github.com/carllerche/tokio-connect" }
+tower-add-origin      = { git = "https://github.com/tower-rs/tower-http" }
 tower-balance         = { git = "https://github.com/tower-rs/tower" }
 tower-buffer          = { git = "https://github.com/tower-rs/tower" }
 tower-discover        = { git = "https://github.com/tower-rs/tower" }

src/control/destination/background/client.rs

@@ -10,9 +10,14 @@ use h2;
 use http;
 use tokio::timer::Delay;
 
-use tower_h2::{self, BoxBody};
+use tower_h2::{self, BoxBody, RecvBody};
+use tower_add_origin::AddOrigin;
 use tower_service::Service;
-use tower_reconnect::{Reconnect, Error as ReconnectError};
+use tower_reconnect::{
+    Reconnect,
+    Error as ReconnectError,
+    ResponseFuture as ReconnectFuture,
+};
 use conditional::Conditional;
 use dns;
 use timeout::{Timeout, TimeoutError};
@@ -20,7 +25,7 @@ use transport::{tls, HostAndPort, LookupAddressAndConnect};
 use watch_service::Rebind;
 
 /// Type of the client service stack used to make destination requests.
-pub(super) type ClientService = AddOrigin<Backoff<LogErrors<Reconnect<
+pub(super) struct ClientService(AddOrigin<Backoff<LogErrors<Reconnect<
         tower_h2::client::Connect<
             Timeout<LookupAddressAndConnect>,
             ::logging::ContextualExecutor<
@@ -31,7 +36,7 @@ pub(super) type ClientService = AddOrigin<Backoff<LogErrors<Reconnect<
             >,
             BoxBody,
         >
-    >>>>;
+    >>>>);
 
 /// The state needed to bind a new controller client stack.
 pub(super) struct BindClient {
@@ -44,23 +49,15 @@ pub(super) struct BindClient {
 
 /// Wait a duration if inner `poll_ready` returns an error.
 //TODO: move to tower-backoff
-pub(super) struct Backoff<S> {
+struct Backoff<S> {
     inner: S,
     timer: Delay,
     waiting: bool,
     wait_dur: Duration,
 }
 
-
-/// Wraps an HTTP service, injecting authority and scheme on every request.
-pub(super) struct AddOrigin<S> {
-    authority: http::uri::Authority,
-    inner: S,
-    scheme: http::uri::Scheme,
-}
-
 /// Log errors talking to the controller in human format.
-pub(super) struct LogErrors<S> {
+struct LogErrors<S> {
     inner: S,
 }
 
@@ -80,6 +77,31 @@ type LogError = ReconnectError<
     >
 >;
 
+// ===== impl ClientService =====
+
+impl Service for ClientService {
+    type Request = http::Request<BoxBody>;
+    type Response = http::Response<RecvBody>;
+    type Error = LogError;
+    type Future = ReconnectFuture<
+        tower_h2::client::Connect<
+            Timeout<LookupAddressAndConnect>,
+            ::logging::ContextualExecutor<
+                ::logging::Client<
+                    &'static str,
+                    HostAndPort,
+                >
+            >, BoxBody>>;
+
+    fn poll_ready(&mut self) -> Poll<(), Self::Error> {
+        self.0.poll_ready()
+    }
+
+    fn call(&mut self, request: Self::Request) -> Self::Future {
+        self.0.call(request)
+    }
+}
+
 // ===== impl BindClient =====
 
 impl BindClient {
@@ -133,8 +155,7 @@ impl Rebind<tls::ConditionalClientConfig> for BindClient {
         let reconnect = Reconnect::new(h2_client);
         let log_errors = LogErrors::new(reconnect);
         let backoff = Backoff::new(log_errors, self.backoff_delay);
-        // TODO: Use AddOrigin in tower-http
-        AddOrigin::new(scheme, authority, backoff)
+        ClientService(AddOrigin::new(backoff, scheme, authority))
     }
 
 }
@@ -145,7 +166,7 @@ impl<S> Backoff<S>
 where
     S: Service,
 {
-    pub(super) fn new(inner: S, wait_dur: Duration) -> Self {
+    fn new(inner: S, wait_dur: Duration) -> Self {
         Backoff {
             inner,
             timer: Delay::new(Instant::now() + wait_dur),
@@ -207,7 +228,7 @@ impl<S> LogErrors<S>
 where
     S: Service<Error=LogError>,
 {
-    pub(super) fn new(service: S) -> Self {
+    fn new(service: S) -> Self {
         LogErrors {
             inner: service,
         }
@@ -235,7 +256,7 @@ where
     }
 }
 
-pub(super) struct HumanError<'a>(&'a LogError);
+struct HumanError<'a>(&'a LogError);
 
 impl<'a> fmt::Display for HumanError<'a> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
@@ -256,42 +277,6 @@ impl<'a> fmt::Display for HumanError<'a> {
     }
 }
 
-// ===== impl AddOrigin =====
-
-impl<S> AddOrigin<S> {
-    pub(super) fn new(scheme: http::uri::Scheme, auth: http::uri::Authority, service: S) -> Self {
-        AddOrigin {
-            authority: auth,
-            inner: service,
-            scheme,
-        }
-    }
-}
-
-impl<S, B> Service for AddOrigin<S>
-where
-    S: Service<Request = http::Request<B>>,
-{
-    type Request = http::Request<B>;
-    type Response = S::Response;
-    type Error = S::Error;
-    type Future = S::Future;
-
-    fn poll_ready(&mut self) -> Poll<(), Self::Error> {
-        self.inner.poll_ready()
-    }
-
-    fn call(&mut self, req: Self::Request) -> Self::Future {
-        let (mut head, body) = req.into_parts();
-        let mut uri: http::uri::Parts = head.uri.into();
-        uri.scheme = Some(self.scheme.clone());
-        uri.authority = Some(self.authority.clone());
-        head.uri = http::Uri::from_parts(uri).expect("valid uri");
-
-        self.inner.call(http::Request::from_parts(head, body))
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;

src/lib.rs

@@ -38,6 +38,7 @@ extern crate tempdir;
 extern crate tokio;
 extern crate tokio_connect;
 extern crate tokio_timer;
+extern crate tower_add_origin;
 extern crate tower_balance;
 extern crate tower_buffer;
 extern crate tower_discover;