fix(codegen): disable signing for sts operations AssumeRoleWithSaml a…

…nd AssumeRoleWithWebIdentity (#407)

codegen/smithy-aws-kotlin-codegen/src/main/kotlin/aws/sdk/kotlin/codegen/customization/sts/StsDisableAuthForOperations.kt

@@ -0,0 +1,43 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0.
+ */
+
+package aws.sdk.kotlin.codegen.customization.sts
+
+import aws.sdk.kotlin.codegen.sdkId
+import software.amazon.smithy.kotlin.codegen.KotlinSettings
+import software.amazon.smithy.kotlin.codegen.integration.KotlinIntegration
+import software.amazon.smithy.kotlin.codegen.model.expectShape
+import software.amazon.smithy.model.Model
+import software.amazon.smithy.model.shapes.OperationShape
+import software.amazon.smithy.model.shapes.ServiceShape
+import software.amazon.smithy.model.shapes.ShapeId
+import software.amazon.smithy.model.traits.AuthTrait
+import software.amazon.smithy.model.transform.ModelTransformer
+
+/**
+ * STS needs to have the auth trait manually set to []
+ *
+ * See https://github.com/awslabs/aws-sdk-kotlin/issues/280
+ */
+class StsDisableAuthForOperations : KotlinIntegration {
+
+    private val optionalAuthOperations = setOf(
+        ShapeId.from("com.amazonaws.sts#AssumeRoleWithSAML"),
+        ShapeId.from("com.amazonaws.sts#AssumeRoleWithWebIdentity")
+    )
+
+    override fun enabledForService(model: Model, settings: KotlinSettings): Boolean =
+        model.expectShape<ServiceShape>(settings.service).sdkId == "STS"
+
+    override fun preprocessModel(model: Model, settings: KotlinSettings): Model =
+        ModelTransformer.create()
+            .mapShapes(model) {
+                if (optionalAuthOperations.contains(it.id) && it is OperationShape) {
+                    it.toBuilder().addTrait(AuthTrait(emptySet())).build()
+                } else {
+                    it
+                }
+            }
+}

codegen/smithy-aws-kotlin-codegen/src/main/resources/META-INF/services/software.amazon.smithy.kotlin.codegen.integration.KotlinIntegration

@@ -16,3 +16,4 @@ aws.sdk.kotlin.codegen.customization.polly.PollyPresigner
 aws.sdk.kotlin.codegen.customization.BoxServices
 aws.sdk.kotlin.codegen.customization.glacier.GlacierBodyChecksum
 aws.sdk.kotlin.codegen.customization.machinelearning.MachineLearningEndpointCustomization
+aws.sdk.kotlin.codegen.customization.sts.StsDisableAuthForOperations