Adding Golang code for Serverless CDK example

v2/serverless_example.md

@@ -79,6 +79,19 @@ cdk init --language csharp
 
 You may now open `src/MyWidgetService.sln` in Visual Studio\.
 
+------
+#### [ Go ]
+
+```
+mkdir MyWidgetService
+cd MyWidgetService
+cdk init --language go
+```
+
+You may now open the Go project in your IDE\.
+
+You may also need to run `go get` and `go mod tidy` before your run `cdk synth` in next steps
+
 ------
 
 **Note**  
@@ -111,6 +124,11 @@ The important files in the blank project are as follows\. \(We will also be addi
 + `src/MyWidgetService/Program.cs` – Main entry point for the application
 + `src/MyWidgetService/MyWidgetServiceStack.cs` – Defines the widget service stack
 
+------
+#### [ Go ]
++ `my_widget_service.go` – Main entry point for the application and service stack
++ `my_widget_service_test.go` – Sample Go test file
+
 ------
 
 Run the app and note that it synthesizes an empty stack\.
@@ -436,7 +454,56 @@ namespace MyWidgetService
 ```
 
 ------
+#### [ Go ]
+
+File: `lib/widget_service.go`
+
+```
+package widgetservice
+
+import (
+	"github.com/aws/aws-cdk-go/awscdk/v2"
+	"github.com/aws/aws-cdk-go/awscdk/v2/awsapigateway"
+	"github.com/aws/aws-cdk-go/awscdk/v2/awslambda"
+	"github.com/aws/aws-cdk-go/awscdk/v2/awss3"
+	"github.com/aws/aws-cdk-go/awscdk/v2/awss3assets"
+	"github.com/aws/constructs-go/constructs/v10"
+	"github.com/aws/jsii-runtime-go"
+)
+
+func WidgetService(scope constructs.Construct, id string) {
+	this := constructs.NewConstruct(scope, &id)
+
+	var bucket = awss3.NewBucket(scope, jsii.String("WidgetStore"), &awss3.BucketProps{})
+
+	var handler = awslambda.NewFunction(this, jsii.String("WidgetHandler"), &awslambda.FunctionProps{
+		Runtime: awslambda.Runtime_NODEJS_16_X(),
+		Code:    awslambda.AssetCode_FromAsset(jsii.String("resources"), &awss3assets.AssetOptions{}),
+		Handler: jsii.String("widgets.main"),
+		Environment: &map[string]*string{
+			"BUCKET": bucket.BucketName(),
+		},
+	})
+
+	bucket.GrantReadWrite(handler, nil)
+
+	api := awsapigateway.NewRestApi(this, jsii.String("widgets-api"), &awsapigateway.RestApiProps{
+		RestApiName: jsii.String("Widget Service Deployed via Go"),
+		Description: jsii.String("This service serves widgets."),
+	})
+
+	getWidgetsIntegration := awsapigateway.NewLambdaIntegration(handler, &awsapigateway.LambdaIntegrationOptions{
+		RequestTemplates: &map[string]*string{
+			"application/json": jsii.String("{ \"statusCode\": 200 }"),
+		},
+	})
 
+	api.Root().AddMethod(jsii.String("GET"), getWidgetsIntegration, &awsapigateway.MethodOptions{
+		ApiKeyRequired: jsii.Bool(false),
+	})
+}
+```
+------
 **Tip**  
 We're using a `[lambda\.Function](https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_lambda.Function.html)` in to deploy this function because it supports a wide variety of programming languages\. For JavaScript and TypeScript specifically, you might consider a `[lambda\-nodejs\.NodejsFunction](https://docs.aws.amazon.com/cdk/api/v2/docs/aws-cdk-lib.aws_lambda_nodejs.NodejsFunction.html)`\. The latter uses esbuild to bundle up the script and converts code written in TypeScript automatically\.
 
@@ -525,6 +592,19 @@ new WidgetService(this, "Widgets");
 
 ------
 
+#### [ Go ]
+
+File: `my_widget_service.go`
+
+Replace the comment in the constructor with the following line of code\.
+
+```
+widgetservice.WidgetService(stack, "Widgets")
+
+```
+Ensure `widgetservice` package has been imported with statement: `"my_widget_service/lib"`
+
+------
 Be sure the app runs and synthesizes a stack \(we won't show the stack here: it's over 250 lines\)\.
 
 ```
@@ -777,6 +857,22 @@ File: `src/MyWidgetService/WidgetService.cs`
 
 ------
 
+#### [ Go ]
+
+File: `lib/my_widget_service.go`
+
+```
+	        widget := api.Root().AddResource(jsii.String("{id}"), nil)
+
+          widgetIntegration := awsapigateway.NewLambdaIntegration       (handler, nil)
+
+	        widget.AddMethod(jsii.String("POST"), widgetIntegration,        nil)   // POST /{id}
+	        widget.AddMethod(jsii.String("GET"), widgetIntegration,         nil)    // GET /{id}
+	        widget.AddMethod(jsii.String("DELETE"), widgetIntegration, nil) // DELETE /{id}
+```
+
+------
+
 Save and deploy the app\.
 
 ```