proxy-http: Remove unneeded boilerplate (#651)

There's a lot of needless boilerplate around the HTTP client, mostly due
to manual future implementations. These have been converted to boxed
futures.

Furthermore, the HasSettings trait has been eliminated, in favor of
AsRef.

Author: olix0r

linkerd/app/core/src/control.rs

@@ -34,7 +34,7 @@ impl fmt::Display for ControlAddr {
 }
 
 type BalanceBody =
-    http::balance::PendingUntilFirstDataBody<tower::load::peak_ewma::Handle, http::glue::Body>;
+    http::balance::PendingUntilFirstDataBody<tower::load::peak_ewma::Handle, hyper::Body>;
 
 type RspBody = linkerd2_http_metrics::requests::ResponseBody<BalanceBody, classify::Eos>;
 

linkerd/app/inbound/src/endpoint.rs

@@ -53,9 +53,9 @@ impl Into<SocketAddr> for HttpEndpoint {
     }
 }
 
-impl http::settings::HasSettings for HttpEndpoint {
-    fn http_settings(&self) -> http::Settings {
-        self.settings
+impl AsRef<http::Settings> for HttpEndpoint {
+    fn as_ref(&self) -> &http::Settings {
+        &self.settings
     }
 }
 
@@ -135,9 +135,9 @@ impl http::normalize_uri::ShouldNormalizeUri for Target {
     }
 }
 
-impl http::settings::HasSettings for Target {
-    fn http_settings(&self) -> http::Settings {
-        self.http_settings
+impl AsRef<http::Settings> for Target {
+    fn as_ref(&self) -> &http::Settings {
+        &self.http_settings
     }
 }
 

linkerd/app/outbound/src/endpoint.rs

@@ -98,22 +98,22 @@ impl<'t, T> From<&'t Target<T>> for http::header::HeaderValue {
     }
 }
 
-impl<T: http::settings::HasSettings> http::normalize_uri::ShouldNormalizeUri for Target<T> {
+impl<T: AsRef<http::Settings>> http::normalize_uri::ShouldNormalizeUri for Target<T> {
     fn should_normalize_uri(&self) -> Option<http::uri::Authority> {
         if let http::Settings::Http1 {
             was_absolute_form: false,
             ..
-        } = self.inner.http_settings()
+        } = *self.inner.as_ref()
         {
             return Some(self.addr.to_http_authority());
         }
         None
     }
 }
 
-impl<T: http::settings::HasSettings> http::settings::HasSettings for Target<T> {
-    fn http_settings(&self) -> http::Settings {
-        self.inner.http_settings()
+impl<T: AsRef<http::Settings>> AsRef<http::Settings> for Target<T> {
+    fn as_ref(&self) -> &http::Settings {
+        self.inner.as_ref()
     }
 }
 
@@ -199,7 +199,7 @@ impl std::hash::Hash for HttpEndpoint {
     fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
         self.addr.hash(state);
         self.identity.hash(state);
-        http::settings::HasSettings::http_settings(self).hash(state);
+        self.settings.hash(state);
         // Ignore metadata.
     }
 }
@@ -216,22 +216,9 @@ impl Into<SocketAddr> for HttpEndpoint {
     }
 }
 
-impl http::settings::HasSettings for HttpEndpoint {
-    fn http_settings(&self) -> http::Settings {
-        match self.settings {
-            Settings::Http1 {
-                keep_alive,
-                wants_h1_upgrade,
-                was_absolute_form,
-            } => Settings::Http1 {
-                keep_alive,
-                wants_h1_upgrade,
-                // Always use absolute form when an onverride is present.
-                was_absolute_form: self.metadata.authority_override().is_some()
-                    || was_absolute_form,
-            },
-            settings => settings,
-        }
+impl AsRef<http::Settings> for HttpEndpoint {
+    fn as_ref(&self) -> &http::Settings {
+        &self.settings
     }
 }
 
@@ -291,14 +278,28 @@ impl MapEndpoint<Concrete<http::Settings>, Metadata> for FromMetadata {
                 Conditional::None(tls::ReasonForNoPeerName::NotProvidedByServiceDiscovery.into())
             });
 
+        let settings = match concrete.inner.inner {
+            Settings::Http1 {
+                keep_alive,
+                wants_h1_upgrade,
+                was_absolute_form,
+            } => Settings::Http1 {
+                keep_alive,
+                wants_h1_upgrade,
+                // Always use absolute form when an onverride is present.
+                was_absolute_form: metadata.authority_override().is_some() || was_absolute_form,
+            },
+            settings => settings,
+        };
+
         Target {
             // Use the logical addr for the target.
             addr: concrete.inner.addr.clone(),
             inner: HttpEndpoint {
                 addr,
                 identity,
                 metadata,
-                settings: concrete.inner.inner,
+                settings,
             },
         }
     }

linkerd/app/outbound/src/orig_proto_upgrade.rs

@@ -1,7 +1,4 @@
-use crate::proxy::http::{
-    orig_proto,
-    settings::{HasSettings, Settings},
-};
+use crate::proxy::http::{orig_proto, settings::Settings};
 use crate::svc::stack;
 use crate::{HttpEndpoint, Target};
 use futures::{ready, TryFuture};
@@ -56,7 +53,7 @@ where
             return Either::B(self.inner.new_service(endpoint));
         }
 
-        let was_absolute = endpoint.http_settings().was_absolute_form();
+        let was_absolute = endpoint.inner.settings.was_absolute_form();
         trace!(
             header = %orig_proto::L5D_ORIG_PROTO,
             was_absolute,
@@ -84,7 +81,7 @@ where
     fn call(&mut self, mut endpoint: Target<HttpEndpoint>) -> Self::Future {
         let can_upgrade = endpoint.inner.can_use_orig_proto();
 
-        let was_absolute = endpoint.http_settings().was_absolute_form();
+        let was_absolute = endpoint.inner.settings.was_absolute_form();
 
         if can_upgrade {
             trace!(