Swift: Hello and Scenario examples for AWS Step Functions

swift/example_code/lambda/using-lambda-runtime/Sources/lambda.swift

@@ -4,7 +4,7 @@
 // snippet-start:[lambda.swift.function.imports]
 import Foundation
 import AWSLambdaRuntime
-import AWSS3
+@preconcurrency import AWSS3
 
 import protocol AWSClientRuntime.AWSServiceError
 import enum Smithy.ByteStream
@@ -38,125 +38,85 @@ enum S3ExampleLambdaErrors: Error {
     /// A required environment variable is missing. The missing variable is
     /// specified.
     case noEnvironmentVariable(String)
-    /// The Amazon Simple Storage Service (S3) client couldn't be created.
-    case noS3Client
 }
 // snippet-end:[lambda.swift.function.errors]
 // snippet-end:[lambda.swift.function.types]
 
-// snippet-start:[lambda.swift.function.handler]
-/// A Swift AWS Lambda Runtime `LambdaHandler` lets you both perform needed
-/// initialization and handle AWS Lambda requests. There are other handler
-/// protocols available for other use cases.
-@main
-struct S3ExampleLambda: LambdaHandler {
-    let s3Client: S3Client?
-
-    // snippet-start:[lambda.swift.function.handler.init]
-    /// Initialize the AWS Lambda runtime.
-    ///
-    /// ^ The logger is a standard Swift logger. You can control the verbosity
-    /// by setting the `LOG_LEVEL` environment variable.
-    init(context: LambdaInitializationContext) async throws {
-        // Display the `LOG_LEVEL` configuration for this process.
-        context.logger.info(
-            "Log Level env var : \(ProcessInfo.processInfo.environment["LOG_LEVEL"] ?? "info" )"
-        )
-
-        // Initialize the Amazon S3 client. This single client is used for every
-        // request.
-        let currentRegion = ProcessInfo.processInfo.environment["AWS_REGION"] ?? "us-east-1"
-        self.s3Client = try? S3Client(region: currentRegion)
-    }
-    // snippet-end:[lambda.swift.function.handler.init]
-
-    // snippet-start:[lambda.swift.function.handler.putobject]
-    /// Write the specified text into a given Amazon S3 bucket. The object's
-    /// name is based on the current time.
-    ///
-    /// - Parameters:
-    ///   - s3Client: The `S3Client` to use when sending the object to the
-    ///     bucket.
-    ///   - bucketName: The name of the Amazon S3 bucket to put the object
-    ///     into.
-    ///   - body: The string to write into the new object.
-    ///
-    /// - Returns: A string indicating the name of the file created in the AWS
-    ///   S3 bucket.
-    private func putObject(client: S3Client, 
-                           bucketName: String,
-                           body: String) async throws -> String {
-        // Generate an almost certainly unique object name based on the current
-        // timestamp.
-        let objectName = "\(Int(Date().timeIntervalSince1970*1_000_000)).txt"
-
-        // Create a Smithy `ByteStream` that represents the string to write into
-        // the bucket.
-        let inputStream = Smithy.ByteStream.data(body.data(using: .utf8))
-
-        // Store the text into an object in the Amazon S3 bucket.
-        let putObjectRequest = PutObjectInput(
+let currentRegion = ProcessInfo.processInfo.environment["AWS_REGION"] ?? "us-east-1"
+let s3Client = try S3Client(region: currentRegion)
+
+// snippet-start:[lambda.swift.function.putobject]
+/// Create a new object on Amazon S3 whose name is based on the current
+/// timestamp, containing the text specified.
+/// 
+/// - Parameters: 
+///   - body: The text to store in the new S3 object.
+///   - bucketName: The name of the Amazon S3 bucket to put the new object
+///     into.
+/// 
+/// - Throws: Errors from `PutObject`.
+/// 
+/// - Returns: The name of the new Amazon S3 object that contains the
+///   specified body text.
+func putObject(body: String, bucketName: String) async throws -> String {
+    // Generate an almost certainly unique object name based on the current
+    // timestamp.
+
+    let objectName = "\(Int(Date().timeIntervalSince1970*1_000_000)).txt"
+
+    // Create a Smithy `ByteStream` that represents the string to write into
+    // the bucket.
+
+    let inputStream = Smithy.ByteStream.data(body.data(using: .utf8))
+
+    // Store the text into an object in the Amazon S3 bucket.
+
+    _ = try await s3Client.putObject(
+        input: PutObjectInput(
             body: inputStream,
             bucket: bucketName,
             key: objectName
         )
-        let _ = try await client.putObject(input: putObjectRequest)
+    )
+
+    // Return the name of the file
+
+    return objectName
+}
+// snippet-end:[lambda.swift.function.putobject]
+
+// snippet-start:[lambda.swift.function.runtime]
+let runtime = LambdaRuntime {
+    (event: Request, context: LambdaContext) async throws -> Response in
 
-        // Return the name of the file.
-        return objectName
+    var responseMessage: String
+
+    // Get the name of the bucket to write the new object into from the
+    // environment variable `BUCKET_NAME`.
+    guard let bucketName = ProcessInfo.processInfo.environment["BUCKET_NAME"] else {
+        context.logger.error("Set the environment variable BUCKET_NAME to the name of the S3 bucket to write files to.")
+        throw S3ExampleLambdaErrors.noEnvironmentVariable("BUCKET_NAME")
     }
-    // snippet-end:[lambda.swift.function.handler.putobject]
-
-    // snippet-start:[lambda.swift.function.handler.handle]
-    /// The Lambda function's entry point. Called by the Lambda runtime.
-    ///
-    /// - Parameters:
-    ///   - event: The `Request` describing the request made by the
-    ///     client.
-    ///   - context: A `LambdaContext` describing the context in
-    ///     which the lambda function is running.
-    ///
-    /// - Returns: A `Response` object that will be encoded to JSON and sent
-    ///   to the client by the Lambda runtime.
-    func handle(_ event: Request, context: LambdaContext) async throws -> Response {
-        // Get the bucket name from the environment.
-        guard let bucketName = ProcessInfo.processInfo.environment["BUCKET_NAME"] else {
-            throw S3ExampleLambdaErrors.noEnvironmentVariable("BUCKET_NAME")
-        }
-
-        // Make sure the `S3Client` is valid.
-        guard let s3Client else {
-            throw S3ExampleLambdaErrors.noS3Client
-        }
-
-        // Call the `putObject` function to store the object on Amazon S3.
-        var responseMessage: String
-        do {
-            let filename = try await putObject(
-                            client: s3Client,
-                            bucketName: bucketName,
-                            body: event.body)
-
-            // Generate the response text.
-            responseMessage = "The Lambda function has successfully stored your data in S3 with name \(filename)'"
-
-            // Send the success notification to the logger.
-            context.logger.info("Data successfully stored in S3.")
-        } catch let error as AWSServiceError {
-            // Generate the error message.
-            responseMessage = "The Lambda function encountered an error and your data was not saved. Root cause: \(error.errorCode ?? "") - \(error.message ?? "")"
-
-            // Send the error message to the logger.
-            context.logger.error("Failed to upload data to Amazon S3.")
-        }
-
-        // Return the response message. The AWS Lambda runtime will send it to the
-        // client.
-        return Response(
-            req_id: context.requestID,
-            body: responseMessage)
+
+    do {
+        let filename = try await putObject(body: event.body, bucketName: bucketName)
+
+        // Generate the response text and update the log.
+        responseMessage = "The Lambda function has successfully stored your data in S3 with name '\(filename)'"
+        context.logger.info("Data successfully stored in S3.")
+    } catch let error as AWSServiceError {
+        // Generate the error message and update the log.
+        responseMessage = "The Lambda function encountered an error and your data was not saved. Root cause: \(error.errorCode ?? "") - \(error.message ?? "")"
+        context.logger.error("Failed to upload data to Amazon S3.")
     }
-    // snippet-end:[lambda.swift.function.handler.handle]
+
+    return Response(req_id: context.requestID, body: responseMessage)
 }
-// snippet-end:[lambda.swift.function.handler]
+// snippet-end:[lambda.swift.function.runtime]
+
+// Start up the runtime.
+
+// snippet-start:[lambda.swift.function.start]
+try await runtime.run()
+// snippet-end:[lambda.swift.function.start]
 // snippet-end:[lambda.swift.function.complete]

swift/example_code/sfn/README.md

@@ -0,0 +1,122 @@
+# Step Functions code examples for the SDK for Swift
+
+## Overview
+
+Shows how to use the AWS SDK for Swift to work with AWS Step Functions.
+
+<!--custom.overview.start-->
+<!--custom.overview.end-->
+
+_Step Functions makes it easy to coordinate the components of distributed applications as a series of steps in a visual workflow._
+
+## ⚠ Important
+
+* Running this code might result in charges to your AWS account. For more details, see [AWS Pricing](https://aws.amazon.com/pricing/) and [Free Tier](https://aws.amazon.com/free/).
+* Running the tests might result in charges to your AWS account.
+* We recommend that you grant your code least privilege. At most, grant only the minimum permissions required to perform the task. For more information, see [Grant least privilege](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html#grant-least-privilege).
+* This code is not tested in every AWS Region. For more information, see [AWS Regional Services](https://aws.amazon.com/about-aws/global-infrastructure/regional-product-services).
+
+<!--custom.important.start-->
+<!--custom.important.end-->
+
+## Code examples
+
+### Prerequisites
+
+For prerequisites, see the [README](../../README.md#Prerequisites) in the `swift` folder.
+
+
+<!--custom.prerequisites.start-->
+<!--custom.prerequisites.end-->
+
+### Basics
+
+Code examples that show you how to perform the essential operations within a service.
+
+- [Learn the basics](scenario/Sources/entry.swift)
+
+
+### Single actions
+
+Code excerpts that show you how to call individual service functions.
+
+- [CreateActivity](scenario/Sources/Activity.swift#L42)
+- [CreateStateMachine](scenario/Sources/StateMachine.swift#L133)
+- [DeleteActivity](scenario/Sources/Activity.swift#L102)
+- [DeleteStateMachine](scenario/Sources/StateMachine.swift#L308)
+- [DescribeExecution](scenario/Sources/StateMachine.swift#L263)
+- [DescribeStateMachine](scenario/Sources/StateMachine.swift#L180)
+- [GetActivityTask](scenario/Sources/StateMachine.swift#L228)
+- [ListActivities](scenario/Sources/Activity.swift#L42)
+- [ListStateMachines](scenario/Sources/StateMachine.swift#L105)
+- [SendTaskSuccess](scenario/Sources/Activity.swift#L115)
+- [StartExecution](scenario/Sources/StateMachine.swift#L205)
+
+
+<!--custom.examples.start-->
+<!--custom.examples.end-->
+
+## Run the examples
+
+### Instructions
+
+To build any of these examples from a terminal window, navigate into its
+directory, then use the following command:
+
+```
+$ swift build
+```
+
+To build one of these examples in Xcode, navigate to the example's directory
+(such as the `ListUsers` directory, to build that example). Then type `xed.`
+to open the example directory in Xcode. You can then use standard Xcode build
+and run commands.
+
+<!--custom.instructions.start-->
+<!--custom.instructions.end-->
+
+
+#### Learn the basics
+
+This example shows you how to do the following:
+
+- Create an activity.
+- Create a state machine from an Amazon States Language definition that contains the previously created activity as a step.
+- Run the state machine and respond to the activity with user input.
+- Get the final status and output after the run completes, then clean up resources.
+
+<!--custom.basic_prereqs.sfn_Scenario_GetStartedStateMachines.start-->
+<!--custom.basic_prereqs.sfn_Scenario_GetStartedStateMachines.end-->
+
+
+<!--custom.basics.sfn_Scenario_GetStartedStateMachines.start-->
+<!--custom.basics.sfn_Scenario_GetStartedStateMachines.end-->
+
+
+### Tests
+
+⚠ Running tests might result in charges to your AWS account.
+
+
+To find instructions for running these tests, see the [README](../../README.md#Tests)
+in the `swift` folder.
+
+
+
+<!--custom.tests.start-->
+<!--custom.tests.end-->
+
+## Additional resources
+
+- [Step Functions Developer Guide](https://docs.aws.amazon.com/step-functions/latest/dg/welcome.html)
+- [Step Functions API Reference](https://docs.aws.amazon.com/step-functions/latest/apireference/Welcome.html)
+- [SDK for Swift Step Functions reference](https://sdk.amazonaws.com/swift/api/awssfn/latest/documentation/awssfn)
+
+<!--custom.resources.start-->
+<!--custom.resources.end-->
+
+---
+
+Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+
+SPDX-License-Identifier: Apache-2.0

swift/example_code/sfn/hello/Package.swift

@@ -0,0 +1,47 @@
+// swift-tools-version: 5.9
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+//
+// (swift-tools-version has two lines here because it needs to be the first
+// line in the file, but it should also appear in the snippet below)
+//
+// snippet-start:[swift.sfn.hello.package]
+// swift-tools-version: 5.9
+//
+// The swift-tools-version declares the minimum version of Swift required to
+// build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "hello-sfn",
+    // Let Xcode know the minimum Apple platforms supported.
+    platforms: [
+        .macOS(.v13),
+        .iOS(.v15)
+    ],
+    dependencies: [
+        // Dependencies declare other packages that this package depends on.
+        .package(
+            url: "https://github.com/awslabs/aws-sdk-swift",
+            from: "1.0.0"),
+        .package(
+            url: "https://github.com/apple/swift-argument-parser.git",
+            branch: "main"
+        )
+    ],
+    targets: [
+        // Targets are the basic building blocks of a package, defining a module or a test suite.
+        // Targets can depend on other targets in this package and products
+        // from dependencies.
+        .executableTarget(
+            name: "hello-sfn",
+            dependencies: [
+                .product(name: "AWSSFN", package: "aws-sdk-swift"),
+                .product(name: "ArgumentParser", package: "swift-argument-parser")
+            ],
+            path: "Sources")
+
+    ]
+)
+// snippet-end:[swift.sfn.hello.package]