[smithy-rs] Establish default max idle connections on default connect…

…ors (#2064)

sdk/aws-smithy-client/src/builder.rs

@@ -87,6 +87,20 @@ use crate::http_connector::ConnectorSettings;
 #[cfg(any(feature = "rustls", feature = "native-tls"))]
 use crate::hyper_ext::Adapter as HyperAdapter;
 
+/// Max idle connections is not standardized across SDKs. Java V1 and V2 use 50, and Go V2 uses 100.
+/// The number below was chosen arbitrarily between those two reference points, and should allow
+/// for 14 separate SDK clients in a Lambda where the max file handles is 1024.
+#[cfg(any(feature = "rustls", feature = "native-tls"))]
+const DEFAULT_MAX_IDLE_CONNECTIONS: usize = 70;
+
+/// Returns default HTTP client settings for hyper.
+#[cfg(any(feature = "rustls", feature = "native-tls"))]
+fn default_hyper_builder() -> hyper::client::Builder {
+    let mut builder = hyper::client::Builder::default();
+    builder.pool_max_idle_per_host(DEFAULT_MAX_IDLE_CONNECTIONS);
+    builder
+}
+
 #[cfg(feature = "rustls")]
 impl<M, R> Builder<(), M, R> {
     /// Connect to the service over HTTPS using Rustls using dynamic dispatch.
@@ -96,6 +110,7 @@ impl<M, R> Builder<(), M, R> {
     ) -> Builder<DynConnector, M, R> {
         self.connector(DynConnector::new(
             HyperAdapter::builder()
+                .hyper_builder(default_hyper_builder())
                 .connector_settings(connector_settings)
                 .build(crate::conns::https()),
         ))
@@ -112,6 +127,7 @@ impl<M, R> Builder<(), M, R> {
     ) -> Builder<DynConnector, M, R> {
         self.connector(DynConnector::new(
             HyperAdapter::builder()
+                .hyper_builder(default_hyper_builder())
                 .connector_settings(connector_settings)
                 .build(crate::conns::native_tls()),
         ))

versions.toml

@@ -1,4 +1,4 @@
-smithy_rs_revision = '6beec943ab767a791a414bbaef1acb4b363f7042'
+smithy_rs_revision = '31f1d35b624bfd4f66d9edb434d9239c36ba4171'
 aws_doc_sdk_examples_revision = 'f88a0edba3961f9d978bf1727054c9414e4fca2b'
 
 [manual_interventions]
@@ -1936,7 +1936,7 @@ source_hash = 'e79e848e80107d8e7bde7ef2e33a85e95bc03a1aa5e074a016d1340ed3ee6fbb'
 [crates.aws-smithy-client]
 category = 'SmithyRuntime'
 version = '0.51.0'
-source_hash = '012fffa414bb08b975517ab72d8ad2dceed3aaffdb96f3fa13e2663654eebf1a'
+source_hash = 'ab3eb841d694f4beaca11518627e11f948b7605170f482542af897acd155f518'
 
 [crates.aws-smithy-eventstream]
 category = 'SmithyRuntime'