add readme + swift-format

Author: sebsto

Examples/HelloWorld/Package.swift

@@ -2,16 +2,16 @@
 
 import PackageDescription
 
+// needed for CI to test the local version of the library
+import class Foundation.ProcessInfo
+import struct Foundation.URL
+
 #if os(macOS)
 let platforms: [PackageDescription.SupportedPlatform]? = [.macOS(.v15)]
 #else
 let platforms: [PackageDescription.SupportedPlatform]? = nil
 #endif
 
-// needed for CI to test the local version of the library
-import class Foundation.ProcessInfo  
-import struct Foundation.URL
-
 let package = Package(
     name: "swift-aws-lambda-runtime-example",
     platforms: platforms,

Examples/HelloWorld/README.md

@@ -1 +1,66 @@
-TO BE DONE
+# Hello World 
+
+This is a simple example of an AWS Lambda function that takes a String as input parameter and returns a String as response.
+
+## Code 
+
+The code creates a `LambdaRuntime` struct. In it's simplest form, it takes a function as argument. The function is the Lambda handler that will be invoked when an event triggers the Lambda function.
+
+The handler is `(event: String, context: LambdaContext) -> String`. The function takes two arguments:
+- the event argument is a `String`. 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 must return a String.
+
+## Build & Package 
+
+To build & archive the package, type the following commands.
+
+```bash
+swift build
+swift package archive --disable-sandbox
+```
+
+If there is no error, there is a ZIP file ready to deploy. 
+The ZIP file is located at `.build/plugins/AWSLambdaPackager/outputs/AWSLambdaPackager/MyLambda/MyLambda.zip`
+
+## Deploy
+
+Here is how to deploy using the `aws` command line.
+
+```bash
+aws lambda create-function \
+--function-name MyLambda \
+--zip-file fileb://.build/plugins/AWSLambdaPackager/outputs/AWSLambdaPackager/MyLambda/MyLambda.zip \
+--runtime provided.al2 \
+--handler provided  \
+--architectures arm64 \
+--role arn:aws:iam::<YOUR_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 replace <YOUR_ACCOUNT_ID> 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 MyLambda \
+--payload $(echo \"Seb\" | base64)  \
+out.txt && cat out.txt && rm out.txt
+```
+
+Note that the payload is expected to be a valid JSON strings, hence the surroundings quotes (`"`).
+
+This should print 
+
+```
+{
+    "StatusCode": 200,
+    "ExecutedVersion": "$LATEST"
+}
+"Hello Seb"
+```

Examples/HelloWorld/Sources/main.swift

@@ -16,8 +16,9 @@ import AWSLambdaRuntime
 
 // in this example we are receiving and responding with strings
 
-let runtime = LambdaRuntime { (event: String, context: LambdaContext) in
-    return "Hello \(event)"
+let runtime = LambdaRuntime {
+    (event: String, context: LambdaContext) in
+    "Hello \(event)"
 }
 
 try await runtime.run()