Ensure identity resolver exists when a credentials provider is given only at operation level

CHANGELOG.next.toml

@@ -46,3 +46,9 @@ message = "Fix code generation for union members with the `@httpPayload` trait."
 references = ["smithy-rs#2969", "smithy-rs#1896"]
 meta = { "breaking" = false, "tada" = false, "bug" = true, "target" = "all" }
 author = "jdisanti"
+
+[[aws-sdk-rust]]
+message = "Fix operation level configuration so that it now sets a) an `IdentityResolver` when a credentials provider is provided only at the operation level and b) a `SigningRegion` when a `Region` is provided only at the operation level."
+references = ["smithy-rs#3021", "aws-sdk-rust#901"]
+meta = { "breaking" = false, "tada" = false, "bug" = true }
+author = "ysaito1001"

aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/CredentialCaches.kt

@@ -57,10 +57,17 @@ class CredentialCacheConfig(codegenContext: ClientCodegenContext) : ConfigCustom
     private val codegenScope = arrayOf(
         *preludeScope,
         "CredentialsCache" to AwsRuntimeType.awsCredentialTypes(runtimeConfig).resolve("cache::CredentialsCache"),
+        "CredentialsIdentityResolver" to AwsRuntimeType.awsRuntime(runtimeConfig)
+            .resolve("identity::credentials::CredentialsIdentityResolver"),
         "DefaultProvider" to defaultProvider(),
+        "SIGV4_SCHEME_ID" to AwsRuntimeType.awsRuntime(runtimeConfig).resolve("auth::sigv4::SCHEME_ID"),
         "SharedAsyncSleep" to RuntimeType.smithyAsync(runtimeConfig).resolve("rt::sleep::SharedAsyncSleep"),
-        "SharedCredentialsCache" to AwsRuntimeType.awsCredentialTypes(runtimeConfig).resolve("cache::SharedCredentialsCache"),
-        "SharedCredentialsProvider" to AwsRuntimeType.awsCredentialTypes(runtimeConfig).resolve("provider::SharedCredentialsProvider"),
+        "SharedCredentialsCache" to AwsRuntimeType.awsCredentialTypes(runtimeConfig)
+            .resolve("cache::SharedCredentialsCache"),
+        "SharedCredentialsProvider" to AwsRuntimeType.awsCredentialTypes(runtimeConfig)
+            .resolve("provider::SharedCredentialsProvider"),
+        "SharedIdentityResolver" to RuntimeType.smithyRuntimeApi(runtimeConfig)
+            .resolve("client::identity::SharedIdentityResolver"),
     )
 
     override fun section(section: ServiceConfig) = writable {
@@ -209,7 +216,14 @@ class CredentialCacheConfig(codegenContext: ClientCodegenContext) : ConfigCustom
                             #{Some}(credentials_cache),
                             #{Some}(credentials_provider),
                         ) => {
-                            resolver.config_mut().store_put(credentials_cache.create_cache(credentials_provider));
+                            let credentials_cache = credentials_cache.create_cache(credentials_provider);
+                            resolver.config_mut().store_put(credentials_cache.clone());
+                            resolver.runtime_components_mut().push_identity_resolver(
+                                #{SIGV4_SCHEME_ID},
+                                #{SharedIdentityResolver}::new(
+                                    #{CredentialsIdentityResolver}::new(credentials_cache),
+                                ),
+                            );
                         }
                     }
                     """,

aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/SigV4SigningDecorator.kt

@@ -120,6 +120,19 @@ class SigV4SigningConfig(
                     )
                 }
             }
+            is ServiceConfig.OperationConfigOverride -> {
+                if (runtimeMode.generateOrchestrator) {
+                    rustTemplate(
+                        """
+                        resolver.config_mut()
+                            .load::<#{Region}>()
+                            .cloned()
+                            .map(|r| resolver.config_mut().store_put(#{SigningRegion}::from(r)));
+                        """,
+                        *codegenScope,
+                    )
+                }
+            }
 
             else -> emptySection
         }

aws/sdk-codegen/src/test/kotlin/software/amazon/smithy/rustsdk/CredentialCacheConfigTest.kt

@@ -19,10 +19,13 @@ internal class CredentialCacheConfigTest {
         namespace com.example
         use aws.protocols#awsJson1_0
         use aws.api#service
+        use aws.auth#sigv4
         use smithy.rules#endpointRuleSet
 
         @service(sdkId: "Some Value")
         @awsJson1_0
+        @sigv4(name: "dontcare")
+        @auth([sigv4])
         @endpointRuleSet({
             "version": "1.0",
             "rules": [{
@@ -39,7 +42,6 @@ internal class CredentialCacheConfigTest {
             version: "1"
         }
 
-        @optionalAuth
         operation SayHello { input: TestInput }
         structure TestInput {
            foo: String,
@@ -58,6 +60,7 @@ internal class CredentialCacheConfigTest {
                     .resolve("cache::CredentialsCache"),
                 "ProvideCachedCredentials" to AwsRuntimeType.awsCredentialTypes(runtimeConfig)
                     .resolve("cache::ProvideCachedCredentials"),
+                "Region" to AwsRuntimeType.awsTypes(runtimeConfig).resolve("region::Region"),
                 "RuntimePlugin" to RuntimeType.smithyRuntimeApi(runtimeConfig)
                     .resolve("client::runtime_plugin::RuntimePlugin"),
                 "SharedCredentialsCache" to AwsRuntimeType.awsCredentialTypes(runtimeConfig)
@@ -186,6 +189,39 @@ internal class CredentialCacheConfigTest {
                         *codegenScope,
                     )
                 }
+
+                tokioTest("test_specifying_credentials_provider_only_at_operation_level_should_work") {
+                    // per https://github.com/awslabs/aws-sdk-rust/issues/901
+                    rustTemplate(
+                        """
+                        let client_config = crate::config::Config::builder().build();
+                        let client = crate::client::Client::from_conf(client_config);
+
+                        let credentials = #{Credentials}::new(
+                            "test",
+                            "test",
+                            #{None},
+                            #{None},
+                            "test",
+                        );
+                        let operation_config_override = crate::config::Config::builder()
+                            .credentials_cache(#{CredentialsCache}::no_caching())
+                            .credentials_provider(credentials.clone())
+                            .region(#{Region}::new("us-west-2"));
+
+                        let _ = client
+                            .say_hello()
+                            .customize()
+                            .await
+                            .unwrap()
+                            .config_override(operation_config_override)
+                            .send()
+                            .await
+                            .expect("success");
+                        """,
+                        *codegenScope,
+                    )
+                }
             }
         }
     }