add HelloJSON example + README (#424)

* add HelloJSON example + README

* multiple corrections of typos and grammatical errors

Co-authored-by: Tim Condon <[email protected]>

Author: sebsto

.github/workflows/pull_request.yml

@@ -35,7 +35,7 @@ jobs:
       # We pass the list of examples here, but we can't pass an array as argument
       # Instead, we pass a String with a valid JSON array.
       # The workaround is mentioned here https://github.com/orgs/community/discussions/11692
-      examples: "[ 'HelloWorld', 'APIGateway','S3_AWSSDK', 'S3_Soto', 'Streaming', 'BackgroundTasks' ]"
+      examples: "[ 'APIGateway', 'BackgroundTasks', 'HelloJSON', 'HelloWorld', 'S3_AWSSDK', 'S3_Soto', 'Streaming' ]"
 
       archive_plugin_enabled: true
 

Examples/HelloJSON/.gitignore

@@ -0,0 +1,4 @@
+response.json
+samconfig.toml
+template.yaml
+Makefile

Examples/HelloJSON/Package.swift

@@ -0,0 +1,59 @@
+// swift-tools-version:6.0
+
+import PackageDescription
+
+// needed for CI to test the local version of the library
+import struct Foundation.URL
+
+#if os(macOS)
+let platforms: [PackageDescription.SupportedPlatform]? = [.macOS(.v15)]
+#else
+let platforms: [PackageDescription.SupportedPlatform]? = nil
+#endif
+
+let package = Package(
+    name: "swift-aws-lambda-runtime-example",
+    platforms: platforms,
+    products: [
+        .executable(name: "HelloJSON", targets: ["HelloJSON"])
+    ],
+    dependencies: [
+        // during CI, the dependency on local version of swift-aws-lambda-runtime is added dynamically below
+        .package(url: "https://github.com/swift-server/swift-aws-lambda-runtime.git", branch: "main")
+    ],
+    targets: [
+        .executableTarget(
+            name: "HelloJSON",
+            dependencies: [
+                .product(name: "AWSLambdaRuntime", package: "swift-aws-lambda-runtime")
+            ]
+        )
+    ]
+)
+
+if let localDepsPath = Context.environment["LAMBDA_USE_LOCAL_DEPS"],
+    localDepsPath != "",
+    let v = try? URL(fileURLWithPath: localDepsPath).resourceValues(forKeys: [.isDirectoryKey]),
+    v.isDirectory == true
+{
+    // when we use the local runtime as deps, let's remove the dependency added above
+    let indexToRemove = package.dependencies.firstIndex { dependency in
+        if case .sourceControl(
+            name: _,
+            location: "https://github.com/swift-server/swift-aws-lambda-runtime.git",
+            requirement: _
+        ) = dependency.kind {
+            return true
+        }
+        return false
+    }
+    if let indexToRemove {
+        package.dependencies.remove(at: indexToRemove)
+    }
+
+    // then we add the dependency on LAMBDA_USE_LOCAL_DEPS' path (typically ../..)
+    print("[INFO] Compiling against swift-aws-lambda-runtime located at \(localDepsPath)")
+    package.dependencies += [
+        .package(name: "swift-aws-lambda-runtime", path: localDepsPath)
+    ]
+}

Examples/HelloJSON/README.md

@@ -0,0 +1,80 @@
+# Hello JSON 
+
+This is a simple example of an AWS Lambda function that takes a JSON structure as an input parameter and returns a JSON structure as a response.
+
+The runtime takes care of decoding the input and encoding the output.
+
+## Code 
+
+The code defines `HelloRequest` and `HelloResponse` data structures to represent the input and output payloads. These structures are typically shared with a client project, such as an iOS application.
+
+The code creates a `LambdaRuntime` struct. In it's simplest form, the initializer takes a function as an argument. The function is the handler that will be invoked when an event triggers the Lambda function.
+
+The handler is `(event: HelloRequest, context: LambdaContext)`. The function takes two arguments:
+- the event argument is a `HelloRequest`. It is the parameter passed when invoking the function.
+- the context argument is a `Lambda Context`. It is a description of the runtime context.
+
+The function return value will be encoded to a `HelloResponse` as your Lambda function response.
+
+## Build & Package 
+
+To build & archive the package, type the following commands.
+
+```bash
+swift package archive --allow-network-connections docker
+```
+
+If there is no error, there is a ZIP file ready to deploy. 
+The ZIP file is located at `.build/plugins/AWSLambdaPackager/outputs/AWSLambdaPackager/HelloJSON/HelloJSON.zip`
+
+## Deploy
+
+Here is how to deploy using the `aws` command line.
+
+```bash
+# Replace with your AWS Account ID
+AWS_ACCOUNT_ID=012345678901
+
+aws lambda create-function \
+--function-name HelloJSON \
+--zip-file fileb://.build/plugins/AWSLambdaPackager/outputs/AWSLambdaPackager/HelloJSON/HelloJSON.zip \
+--runtime provided.al2 \
+--handler provided  \
+--architectures arm64 \
+--role arn:aws:iam::${AWS_ACCOUNT_ID}:role/lambda_basic_execution
+```
+
+The `--architectures` flag is only required when you build the binary on an Apple Silicon machine (Apple M1 or more recent). It defaults to `x64`.
+
+Be sure to define the `AWS_ACCOUNT_ID` environment variable with your actual AWS account ID (for example: 012345678901).
+
+## Invoke your Lambda function
+
+To invoke the Lambda function, use this `aws` command line.
+
+```bash
+aws lambda invoke \
+--function-name HelloJSON \
+--payload $(echo '{ "name" : "Seb", "age" : 50 }' | base64)  \
+out.txt && cat out.txt && rm out.txt
+```
+
+Note that the payload is expected to be a valid JSON string.
+
+This should output the following result. 
+
+```
+{
+    "StatusCode": 200,
+    "ExecutedVersion": "$LATEST"
+}
+{"greetings":"Hello Seb. You look younger than your age."}
+```
+
+## Undeploy
+
+When done testing, you can delete the Lambda function with this command.
+
+```bash
+aws lambda delete-function --function-name HelloJSON
+```

Examples/HelloJSON/Sources/main.swift

@@ -0,0 +1,40 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftAWSLambdaRuntime open source project
+//
+// Copyright (c) 2024 Apple Inc. and the SwiftAWSLambdaRuntime project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftAWSLambdaRuntime project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import AWSLambdaRuntime
+
+// in this example we are receiving and responding with JSON structures
+
+// the data structure to represent the input parameter
+struct HelloRequest: Decodable {
+    let name: String
+    let age: Int
+}
+
+// the data structure to represent the output response
+struct HelloResponse: Encodable {
+    let greetings: String
+}
+
+// the Lambda runtime
+let runtime = LambdaRuntime {
+    (event: HelloRequest, context: LambdaContext) in
+
+    HelloResponse(
+        greetings: "Hello \(event.name). You look \(event.age > 30 ? "younger" : "older") than your age."
+    )
+}
+
+// start the loop
+try await runtime.run()

Examples/README.md

@@ -18,6 +18,8 @@ This directory contains example code for Lambda functions.
 
 - **[BackgroundTasks](BackgroundTasks/README.md)**: a Lambda function that continues to run background tasks after having sent the response (requires [AWS CLI](https://docs.aws.amazon.com/cli/latest/userguide/getting-started-install.html)).
 
+- **[HelloJSON](HelloJSON/README.md)**: a Lambda function that accepts JSON as an input parameter and responds with a JSON output (requires [AWS CLI](https://docs.aws.amazon.com/cli/latest/userguide/getting-started-install.html)).
+
 - **[HelloWorld](HelloWorld/README.md)**: a simple Lambda function (requires [AWS CLI](https://docs.aws.amazon.com/cli/latest/userguide/getting-started-install.html)).
 
 - **[S3_AWSSDK](S3_AWSSDK/README.md)**: a Lambda function that uses the [AWS SDK for Swift](https://docs.aws.amazon.com/sdk-for-swift/latest/developer-guide/getting-started.html) to invoke an [Amazon S3](https://docs.aws.amazon.com/AmazonS3/latest/userguide/Welcome.html) API (requires [AWS SAM](https://aws.amazon.com/serverless/sam/)).

Plugins/AWSLambdaPackager/Plugin.swift

@@ -74,7 +74,7 @@ struct AWSLambdaPackager: CommandPlugin {
             "\(archives.count > 0 ? archives.count.description : "no") archive\(archives.count != 1 ? "s" : "") created"
         )
         for (product, archivePath) in archives {
-            print("  * \(product.name) at \(archivePath)")
+            print("  * \(product.name) at \(archivePath.path())")
         }
     }
 

Plugins/AWSLambdaPackager/PluginUtils.swift

@@ -28,6 +28,9 @@ struct Utils {
     ) throws -> String {
         if logLevel >= .debug {
             print("\(executable.path()) \(arguments.joined(separator: " "))")
+            if let customWorkingDirectory {
+                print("Working directory: \(customWorkingDirectory.path())")
+            }
         }
 
         let fd = dup(1)
@@ -85,8 +88,8 @@ struct Utils {
         process.standardError = pipe
         process.executableURL = executable
         process.arguments = arguments
-        if let workingDirectory = customWorkingDirectory {
-            process.currentDirectoryURL = URL(fileURLWithPath: workingDirectory.path())
+        if let customWorkingDirectory {
+            process.currentDirectoryURL = URL(fileURLWithPath: customWorkingDirectory.path())
         }
         process.terminationHandler = { _ in
             outputQueue.async {