feat: Add SSO credentials provider (#1084)

* Add SSO credentials provider wrapper & unit test cases.
---------

Co-authored-by: Sichan Yoo <chanyoo@amazon.com>

Sources/Core/AWSClientRuntime/Auth/CredentialsProviders/SSOCredentialsProvider.swift

@@ -0,0 +1,36 @@
+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import AwsCommonRuntimeKit
+import ClientRuntime
+
+/// A credentials provider that sources credentials using GetRoleCredentialsRequest to the AWS Single Sign-On Service to maintain short-lived sessions.
+/// [Details link](https://docs.aws.amazon.com/sdkref/latest/guide/feature-sso-credentials.html)
+public struct SSOCredentialsProvider: CredentialsSourcedByCRT {
+    let crtCredentialsProvider: CRTCredentialsProvider
+
+    /// - Parameters:
+    ///   - profileName: The profile name to use. If not provided it will be resolved internally via the `AWS_PROFILE` environment variable or defaulted to `default` if not configured.
+    ///   - configFilePath: The path to the configuration file to use. If not provided it will be resolved internally via the `AWS_CONFIG_FILE` environment variable or defaulted  to `~/.aws/config` if not configured.
+    ///   - credentialsFilePath: The path to the shared credentials file to use. If not provided it will be resolved internally via the `AWS_SHARED_CREDENTIALS_FILE` environment variable or defaulted `~/.aws/credentials` if not configured.
+    public init(
+        profileName: String? = nil,
+        configFilePath: String? = nil,
+        credentialsFilePath: String? = nil
+    ) throws {
+        let fileBasedConfig = try CRTFileBasedConfiguration(
+            configFilePath: configFilePath,
+            credentialsFilePath: credentialsFilePath
+        )
+        self.crtCredentialsProvider = try CRTCredentialsProvider(source: .sso(
+            bootstrap: SDKDefaultIO.shared.clientBootstrap,
+            tlsContext: SDKDefaultIO.shared.tlsContext,
+            fileBasedConfiguration: fileBasedConfig,
+            profileFileNameOverride: profileName
+        ))
+    }
+}

Tests/Core/AWSClientRuntimeTests/Auth/CredentialsProvidersTests/SSOCredentialsProviderTests.swift

@@ -0,0 +1,47 @@
+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import ClientRuntime
+import Foundation
+import XCTest
+
+@_spi(FileBasedConfig) @testable import AWSClientRuntime
+
+class SSOCredentialsProviderTests: XCTestCase {
+    let configPath = Bundle.module.path(forResource: "sso_tests", ofType: nil)!
+    let credentialsPath = Bundle.module.path(forResource: "credentials", ofType: nil)!
+
+    func testCreateCredentialsProviderSSONonexistentProfile() async throws {
+        XCTAssertThrowsError(try SSOCredentialsProvider(
+            profileName: "PROFILE_NOT_IN_SSO_TESTS_CONFIG_FILE",
+            configFilePath: configPath,
+            credentialsFilePath: credentialsPath
+            )
+        )
+    }
+
+    func testCreateCredentialsProviderSSOLegacyProfile() async throws {
+        _ = try SSOCredentialsProvider(
+            profileName: "user",
+            configFilePath: configPath,
+            credentialsFilePath: credentialsPath
+        )
+        // SUCCESS: creation didn't throw error
+    }
+
+    func testCreateCredentialsProviderSSOTokenProviderProfile() async throws {
+        _ = try SSOCredentialsProvider(
+            profileName: "dev",
+            configFilePath: configPath,
+            credentialsFilePath: credentialsPath
+        )
+        // SUCCESS: creation didn't throw error
+    }
+
+    // TODO: add integration tests that automatically test that SSO crednetials provider correctly exchanges SSO token for temporary AWS credentails.
+    // Manual integration testing confirmed SSOCredentialsProvider works as of 081723.
+}

Tests/Core/AWSClientRuntimeTests/Resources/sso_tests

@@ -0,0 +1,17 @@
+[profile dev]
+sso_session = my-sso
+sso_account_id = 111122223333
+sso_role_name = SampleRole
+
+[sso-session my-sso]
+sso_region = us-east-1
+sso_start_url = https://my-sso-portal.awsapps.com/start
+sso_registration_scopes = sso:account:access
+
+[profile user]
+aws_access_key_id = example_access_key_id
+aws_secret_access_key = example_secret_access_key
+sso_start_url = https://d-test.awsapps.com/start
+sso_region = us-west-2
+sso_account_id = 12345
+sso_role_name = roleName