chore(example): Add CDK example for Layer

Author: Florian Chazal

Diff for: examples/cdk/.gitignore

@@ -6,3 +6,4 @@ node_modules
 # CDK asset staging directory
 .cdk.staging
 cdk.out
+lib

Diff for: examples/cdk/src/example-function.ts

@@ -1,31 +1,54 @@
-import { custom_resources, aws_iam } from 'aws-cdk-lib';
+import { custom_resources, aws_iam, Stack } from 'aws-cdk-lib';
 import { Events } from '@aws-lambda-powertools/commons';
 import { Construct } from 'constructs';
 import { NodejsFunction, NodejsFunctionProps } from 'aws-cdk-lib/aws-lambda-nodejs';
-import { Tracing, Runtime } from 'aws-cdk-lib/aws-lambda';
+import { Tracing, Runtime, LayerVersion } from 'aws-cdk-lib/aws-lambda';
 
 interface ExampleFunctionProps {
   readonly functionName: string
   readonly tracingActive?: boolean
+  readonly useLayer?: boolean
   readonly invocations?: number
   readonly fnProps?: Partial<NodejsFunctionProps>
 }
 
 class ExampleFunction extends Construct {
-
   public constructor(scope: Construct, id: string, props: ExampleFunctionProps) {
     super(scope, id);
 
-    const { functionName, tracingActive, invocations, fnProps } = Object.assign({
-      tracingActive: false,
-      invocations: 2
-    }, props);
+    const { functionName, tracingActive, invocations, fnProps } = Object.assign(
+      {
+        tracingActive: false,
+        invocations: 2,
+      },
+      props
+    );
 
-    const fn = new NodejsFunction(this, functionName, {
+    const fnOptions = {
       tracing: tracingActive ? Tracing.ACTIVE : Tracing.DISABLED,
       runtime: Runtime.NODEJS_16_X,
-      ...fnProps
-    });
+      ...fnProps,
+    };
+
+    if (props.useLayer) {
+      fnOptions.bundling = {
+        externalModules: [
+          '@aws-lambda-powertools/commons',
+          '@aws-lambda-powertools/logger',
+          '@aws-lambda-powertools/metrics',
+          '@aws-lambda-powertools/tracer',
+        ],
+      };
+      fnOptions.layers = [
+        LayerVersion.fromLayerVersionArn(
+          this,
+          'AWSLambdaPowertoolsTypeScript',
+          `arn:aws:lambda:${Stack.of(this).region}:094274105915:layer:AWSLambdaPowertoolsTypeScript:1`
+        ),
+      ];
+    }
+
+    const fn = new NodejsFunction(this, functionName, fnOptions);
 
     for (let i = 0; i < invocations; i++) {
       new custom_resources.AwsCustomResource(this, `Invoke-${functionName}-${i}`, {
@@ -37,14 +60,12 @@ class ExampleFunction extends Construct {
             FunctionName: fn.functionName,
             InvocationType: 'RequestResponse',
             Payload: JSON.stringify(Events.Custom.CustomEvent),
-          }
+          },
         },
         policy: custom_resources.AwsCustomResourcePolicy.fromStatements([
           new aws_iam.PolicyStatement({
             effect: aws_iam.Effect.ALLOW,
-            resources: [
-              fn.functionArn,
-            ],
+            resources: [fn.functionArn],
             actions: ['lambda:InvokeFunction'],
           }),
         ]),
@@ -53,6 +74,4 @@ class ExampleFunction extends Construct {
   }
 }
 
-export {
-  ExampleFunction
-};
+export { ExampleFunction };

Diff for: examples/cdk/src/example-layer.ts

@@ -1,6 +1,6 @@
 import { Stack, StackProps } from 'aws-cdk-lib';
 import { Construct } from 'constructs';
-import { LayeredFunction } from './example-layer';
+import path from 'path';
 import { ExampleFunction } from './example-function';
 
 export class CdkAppStack extends Stack {
@@ -67,9 +67,13 @@ export class CdkAppStack extends Stack {
       tracingActive: true,
     });
 
-    new LayeredFunction(this, 'MyLayeredFunction', {
+    new ExampleFunction(this, 'MyLayeredFunction', {
       functionName: 'MyLayeredFunction',
       tracingActive: true,
+      useLayer: true,
+      fnProps: {
+        entry: path.join(__dirname, 'example-function.MyFunction.ts')
+      }
     });
   }
 }

Diff for: examples/cdk/src/example-stack.ts

@@ -32,7 +32,7 @@ Object {
           "S3Bucket": Object {
             "Fn::Sub": "cdk-hnb659fds-assets-\${AWS::AccountId}-\${AWS::Region}",
           },
-          "S3Key": "6eba0de0afc84e169557e039f71f823118dc01c239decea38379b17d3edee2d3.zip",
+          "S3Key": "5515bb957e431a552cb488700a1cd7219009aac6faaced018852b8d8fdc61946.zip",
         },
         "Description": "Lambda Powertools for TypeScript version 1.0.1",
         "LayerName": "AWSLambdaPowertoolsTypeScript",