Set up a default connector for generic clients in the orchestrator implementation (#2693)

## Motivation and Context
This PR makes generic clients default to the built-in rustls HTTPS
connector when no override is provided, but only for the new
orchestrator implementation.

----

_By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of your
choice._

Author: jdisanti

aws/rust-runtime/aws-config/Cargo.toml

@@ -10,7 +10,7 @@ repository = "https://github.com/awslabs/smithy-rs"
 
 [features]
 client-hyper = ["aws-smithy-client/client-hyper"]
-rustls = ["aws-smithy-client/rustls"]
+rustls = ["aws-smithy-client/rustls", "client-hyper"]
 native-tls = []
 allow-compilation = [] # our tests use `cargo test --all-features` and native-tls breaks CI
 rt-tokio = ["aws-smithy-async/rt-tokio", "tokio/rt"]

aws/rust-runtime/aws-config/external-types.toml

@@ -10,6 +10,7 @@ allowed_external_types = [
    "aws_sdk_sts::types::_policy_descriptor_type::PolicyDescriptorType",
    "aws_smithy_async::rt::sleep::AsyncSleep",
    "aws_smithy_client::bounds::SmithyConnector",
+   "aws_smithy_client::conns::default_connector::default_connector",
    "aws_smithy_client::erase::DynConnector",
    "aws_smithy_client::erase::boxclone::BoxCloneService",
    "aws_smithy_client::http_connector::ConnectorSettings",

aws/rust-runtime/aws-config/src/connector.rs

@@ -5,49 +5,25 @@
 
 //! Functionality related to creating new HTTP Connectors
 
-use aws_smithy_async::rt::sleep::AsyncSleep;
 use aws_smithy_client::erase::DynConnector;
-use aws_smithy_client::http_connector::ConnectorSettings;
-use std::sync::Arc;
 
 // unused when all crate features are disabled
 /// Unwrap an [`Option<DynConnector>`](aws_smithy_client::erase::DynConnector), and panic with a helpful error message if it's `None`
 pub(crate) fn expect_connector(connector: Option<DynConnector>) -> DynConnector {
     connector.expect("No HTTP connector was available. Enable the `rustls` crate feature or set a connector to fix this.")
 }
 
+#[cfg(feature = "client-hyper")]
+pub use aws_smithy_client::conns::default_connector;
+
 #[cfg(all(feature = "native-tls", not(feature = "allow-compilation")))]
 compile_error!("Feature native-tls has been removed. For upgrade instructions, see: https://awslabs.github.io/smithy-rs/design/transport/connector.html");
 
-#[cfg(feature = "rustls")]
-fn base(
-    settings: &ConnectorSettings,
-    sleep: Option<Arc<dyn AsyncSleep>>,
-) -> aws_smithy_client::hyper_ext::Builder {
-    let mut hyper =
-        aws_smithy_client::hyper_ext::Adapter::builder().connector_settings(settings.clone());
-    if let Some(sleep) = sleep {
-        hyper = hyper.sleep_impl(sleep);
-    }
-    hyper
-}
-
-/// Given `ConnectorSettings` and an `AsyncSleep`, create a `DynConnector` from defaults depending on what cargo features are activated.
-#[cfg(feature = "rustls")]
-pub fn default_connector(
-    settings: &ConnectorSettings,
-    sleep: Option<Arc<dyn AsyncSleep>>,
-) -> Option<DynConnector> {
-    tracing::trace!(settings = ?settings, sleep = ?sleep, "creating a new connector");
-    let hyper = base(settings, sleep).build(aws_smithy_client::conns::https());
-    Some(DynConnector::new(hyper))
-}
-
 /// Given `ConnectorSettings` and an `AsyncSleep`, create a `DynConnector` from defaults depending on what cargo features are activated.
-#[cfg(not(feature = "rustls"))]
+#[cfg(not(feature = "client-hyper"))]
 pub fn default_connector(
-    _settings: &ConnectorSettings,
-    _sleep: Option<Arc<dyn AsyncSleep>>,
+    _settings: &aws_smithy_client::http_connector::ConnectorSettings,
+    _sleep: Option<std::sync::Arc<dyn aws_smithy_async::rt::sleep::AsyncSleep>>,
 ) -> Option<DynConnector> {
     None
 }

codegen-client/src/main/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/ServiceRuntimePluginGenerator.kt

@@ -63,6 +63,7 @@ class ServiceRuntimePluginGenerator(
     private val endpointTypesGenerator = EndpointTypesGenerator.fromContext(codegenContext)
     private val codegenScope = codegenContext.runtimeConfig.let { rc ->
         val http = RuntimeType.smithyHttp(rc)
+        val client = RuntimeType.smithyClient(rc)
         val runtime = RuntimeType.smithyRuntime(rc)
         val runtimeApi = RuntimeType.smithyRuntimeApi(rc)
         arrayOf(
@@ -77,6 +78,7 @@ class ServiceRuntimePluginGenerator(
             "DefaultEndpointResolver" to runtime.resolve("client::orchestrator::endpoints::DefaultEndpointResolver"),
             "DynConnectorAdapter" to runtime.resolve("client::connections::adapter::DynConnectorAdapter"),
             "HttpAuthSchemes" to runtimeApi.resolve("client::auth::HttpAuthSchemes"),
+            "HttpConnector" to client.resolve("http_connector::HttpConnector"),
             "IdentityResolvers" to runtimeApi.resolve("client::identity::IdentityResolvers"),
             "InterceptorRegistrar" to runtimeApi.resolve("client::interceptors::InterceptorRegistrar"),
             "NeverRetryStrategy" to runtime.resolve("client::retries::strategy::NeverRetryStrategy"),
@@ -85,6 +87,8 @@ class ServiceRuntimePluginGenerator(
             "RuntimePlugin" to runtimeApi.resolve("client::runtime_plugin::RuntimePlugin"),
             "SharedEndpointResolver" to http.resolve("endpoint::SharedEndpointResolver"),
             "StaticAuthOptionResolver" to runtimeApi.resolve("client::auth::option_resolver::StaticAuthOptionResolver"),
+            "default_connector" to client.resolve("conns::default_connector"),
+            "require_connector" to client.resolve("conns::require_connector"),
         )
     }
 
@@ -121,15 +125,20 @@ class ServiceRuntimePluginGenerator(
                         #{SharedEndpointResolver}::from(self.handle.conf.endpoint_resolver()));
                     cfg.set_endpoint_resolver(endpoint_resolver);
 
-                    // TODO(RuntimePlugins): Wire up standard retry
+                    // TODO(enableNewSmithyRuntime): Wire up standard retry
                     cfg.set_retry_strategy(#{NeverRetryStrategy}::new());
 
-                    // TODO(RuntimePlugins): Replace this with the correct long-term solution
                     let sleep_impl = self.handle.conf.sleep_impl();
-                    let connection: #{Box}<dyn #{Connection}> = self.handle.conf.http_connector()
-                            .and_then(move |c| c.connector(&#{ConnectorSettings}::default(), sleep_impl))
-                            .map(|c| #{Box}::new(#{DynConnectorAdapter}::new(c)) as _)
-                            .expect("connection set");
+                    let timeout_config = self.handle.conf.timeout_config();
+                    let connector_settings = timeout_config.map(|c| #{ConnectorSettings}::from_timeout_config(c)).unwrap_or_default();
+                    let connection: #{Box}<dyn #{Connection}> = #{Box}::new(#{DynConnectorAdapter}::new(
+                        // TODO(enableNewSmithyRuntime): Replace the tower-based DynConnector and remove DynConnectorAdapter when deleting the middleware implementation
+                        #{require_connector}(
+                            self.handle.conf.http_connector()
+                                .and_then(|c| c.connector(&connector_settings, sleep_impl.clone()))
+                                .or_else(|| #{default_connector}(&connector_settings, sleep_impl))
+                        )?
+                    )) as _;
                     cfg.set_connection(connection);
 
                     #{additional_config}

rust-runtime/aws-smithy-client/src/conns.rs

@@ -5,6 +5,8 @@
 
 //! Type aliases for standard connection types.
 
+use crate::erase::DynConnector;
+
 #[cfg(feature = "rustls")]
 /// A `hyper` connector that uses the `rustls` crate for TLS. To use this in a smithy client,
 /// wrap it in a [hyper_ext::Adapter](crate::hyper_ext::Adapter).
@@ -49,6 +51,64 @@ lazy_static::lazy_static! {
     };
 }
 
+mod default_connector {
+    use crate::erase::DynConnector;
+    use crate::http_connector::ConnectorSettings;
+    use aws_smithy_async::rt::sleep::AsyncSleep;
+    use std::sync::Arc;
+
+    #[cfg(feature = "rustls")]
+    fn base(
+        settings: &ConnectorSettings,
+        sleep: Option<Arc<dyn AsyncSleep>>,
+    ) -> crate::hyper_ext::Builder {
+        let mut hyper = crate::hyper_ext::Adapter::builder().connector_settings(settings.clone());
+        if let Some(sleep) = sleep {
+            hyper = hyper.sleep_impl(sleep);
+        }
+        hyper
+    }
+
+    /// Given `ConnectorSettings` and an `AsyncSleep`, create a `DynConnector` from defaults depending on what cargo features are activated.
+    pub fn default_connector(
+        settings: &ConnectorSettings,
+        sleep: Option<Arc<dyn AsyncSleep>>,
+    ) -> Option<DynConnector> {
+        #[cfg(feature = "rustls")]
+        {
+            tracing::trace!(settings = ?settings, sleep = ?sleep, "creating a new default connector");
+            let hyper = base(settings, sleep).build(super::https());
+            Some(DynConnector::new(hyper))
+        }
+        #[cfg(not(feature = "rustls"))]
+        {
+            tracing::trace!(settings = ?settings, sleep = ?sleep, "no default connector available");
+            None
+        }
+    }
+}
+pub use default_connector::default_connector;
+
+/// Error that indicates a connector is required.
+#[non_exhaustive]
+#[derive(Debug, Default)]
+pub struct ConnectorRequiredError;
+
+impl std::fmt::Display for ConnectorRequiredError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str("No HTTP connector was available. Enable the `rustls` crate feature or set a connector to fix this.")
+    }
+}
+
+impl std::error::Error for ConnectorRequiredError {}
+
+/// Converts an optional connector to a result.
+pub fn require_connector(
+    connector: Option<DynConnector>,
+) -> Result<DynConnector, ConnectorRequiredError> {
+    connector.ok_or(ConnectorRequiredError)
+}
+
 #[cfg(feature = "rustls")]
 /// Return a default HTTPS connector backed by the `rustls` crate.
 ///