Make it possible to nest runtime components

CHANGELOG.next.toml

@@ -23,6 +23,12 @@ references = ["smithy-rs#2904"]
 meta = { "breaking" = false, "tada" = false, "bug" = false, "target" = "client" }
 author = "jdisanti"
 
+[[smithy-rs]]
+message = "It's now possible to nest runtime components with the `RuntimePlugin` trait. A `current_components` argument was added to the `runtime_components` method so that components configured from previous runtime plugins can be referenced in the current runtime plugin. Ordering of runtime plugins was also introduced via a new `RuntimePlugin::order` method."
+references = ["smithy-rs#2909"]
+meta = { "breaking" = true, "tada" = false, "bug" = false, "target" = "client"}
+author = "jdisanti"
+
 [[smithy-rs]]
 message = "Fix incorrect summary docs for builders"
 references = ["smithy-rs#2914", "aws-sdk-rust#825"]

aws/rust-runtime/aws-inlineable/src/presigning_interceptors.rs

@@ -118,7 +118,10 @@ impl RuntimePlugin for SigV4PresigningRuntimePlugin {
         Some(layer.freeze())
     }
 
-    fn runtime_components(&self) -> Cow<'_, RuntimeComponentsBuilder> {
+    fn runtime_components(
+        &self,
+        _: &RuntimeComponentsBuilder,
+    ) -> Cow<'_, RuntimeComponentsBuilder> {
         Cow::Borrowed(&self.runtime_components)
     }
 }

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

@@ -73,7 +73,7 @@ class ConfigOverrideRuntimePluginGenerator(
                     Some(self.config.clone())
                 }
 
-                fn runtime_components(&self) -> #{Cow}<'_, #{RuntimeComponentsBuilder}> {
+                fn runtime_components(&self, _: &#{RuntimeComponentsBuilder}) -> #{Cow}<'_, #{RuntimeComponentsBuilder}> {
                     #{Cow}::Borrowed(&self.components)
                 }
             }

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

@@ -76,7 +76,7 @@ class OperationRuntimePluginGenerator(
                     #{Some}(cfg.freeze())
                 }
 
-                fn runtime_components(&self) -> #{Cow}<'_, #{RuntimeComponentsBuilder}> {
+                fn runtime_components(&self, _: &#{RuntimeComponentsBuilder}) -> #{Cow}<'_, #{RuntimeComponentsBuilder}> {
                     // Retry classifiers are operation-specific because they need to downcast operation-specific error types.
                     let retry_classifiers = #{RetryClassifiers}::new()
                         #{retry_classifier_customizations};

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

@@ -121,7 +121,7 @@ class ServiceRuntimePluginGenerator(
                     self.config.clone()
                 }
 
-                fn runtime_components(&self) -> #{Cow}<'_, #{RuntimeComponentsBuilder}> {
+                fn runtime_components(&self, _: &#{RuntimeComponentsBuilder}) -> #{Cow}<'_, #{RuntimeComponentsBuilder}> {
                     #{Cow}::Borrowed(&self.runtime_components)
                 }
             }

codegen-client/src/test/kotlin/software/amazon/smithy/rust/codegen/client/smithy/generators/ConfigOverrideRuntimePluginGeneratorTest.kt

@@ -49,6 +49,7 @@ internal class ConfigOverrideRuntimePluginGeneratorTest {
                 "EndpointResolverParams" to RuntimeType.smithyRuntimeApi(runtimeConfig)
                     .resolve("client::endpoint::EndpointResolverParams"),
                 "RuntimePlugin" to RuntimeType.runtimePlugin(runtimeConfig),
+                "RuntimeComponentsBuilder" to RuntimeType.runtimeComponentsBuilder(runtimeConfig),
             )
             rustCrate.testModule {
                 addDependency(CargoDependency.Tokio.toDevDependency().withFeature("test-util"))
@@ -67,7 +68,8 @@ internal class ConfigOverrideRuntimePluginGeneratorTest {
                             client_config.config,
                             &client_config.runtime_components,
                         );
-                        let sut_components = sut.runtime_components();
+                        let prev = #{RuntimeComponentsBuilder}::new("prev");
+                        let sut_components = sut.runtime_components(&prev);
                         let endpoint_resolver = sut_components.endpoint_resolver().unwrap();
                         let endpoint = endpoint_resolver
                             .resolve_endpoint(&#{EndpointResolverParams}::new(crate::config::endpoint::Params {}))

rust-runtime/aws-smithy-runtime-api/Cargo.toml

@@ -25,6 +25,9 @@ tokio = { version = "1.25", features = ["sync"] }
 tracing = "0.1"
 zeroize = { version = "1", optional = true }
 
+[dev-dependencies]
+tokio = { version = "1.25", features = ["rt", "macros"] }
+
 [package.metadata.docs.rs]
 all-features = true
 targets = ["x86_64-unknown-linux-gnu"]