feat(custom-resources): fixed Lambda function name (#17670)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: cyuste

packages/@aws-cdk/custom-resources/README.md

@@ -347,6 +347,25 @@ This sample demonstrates the following concepts:
 * Non-intrinsic physical IDs
 * Implemented in Python
 
+
+### Customizing Provider Function name
+
+In multi-account environments or when the custom resource may be re-utilized across several 
+stacks it may be useful to manually set a name for the Provider Function Lambda and therefore
+have a predefined service token ARN.
+
+```ts
+
+const myProvider = new cr.Provider(this, 'MyProvider', {
+  onEventHandler: onEvent,
+  isCompleteHandler: isComplete,
+  logRetention: logs.RetentionDays.ONE_DAY,
+  role: myRole,
+  providerFunctionName: 'the-lambda-name',   // Optional
+});
+
+```
+
 ## Custom Resources for AWS APIs
 
 Sometimes a single API call can fill the gap in the CloudFormation coverage. In

packages/@aws-cdk/custom-resources/lib/provider-framework/provider.ts

@@ -115,6 +115,15 @@ export interface ProviderProps {
    * @default - A default role will be created.
    */
   readonly role?: iam.IRole;
+
+  /**
+   * Provider Lambda name.
+   *
+   * The provider lambda function name.
+   *
+   * @default -  CloudFormation default name from unique physical ID
+   */
+  readonly providerFunctionName?: string;
 }
 
 /**
@@ -165,7 +174,7 @@ export class Provider extends CoreConstruct implements ICustomResourceProvider {
 
     this.role = props.role;
 
-    const onEventFunction = this.createFunction(consts.FRAMEWORK_ON_EVENT_HANDLER_NAME);
+    const onEventFunction = this.createFunction(consts.FRAMEWORK_ON_EVENT_HANDLER_NAME, props.providerFunctionName);
 
     if (this.isCompleteHandler) {
       const isCompleteFunction = this.createFunction(consts.FRAMEWORK_IS_COMPLETE_HANDLER_NAME);
@@ -198,7 +207,7 @@ export class Provider extends CoreConstruct implements ICustomResourceProvider {
     };
   }
 
-  private createFunction(entrypoint: string) {
+  private createFunction(entrypoint: string, name?: string) {
     const fn = new lambda.Function(this, `framework-${entrypoint}`, {
       code: lambda.Code.fromAsset(RUNTIME_HANDLER_PATH),
       description: `AWS CDK resource provider framework - ${entrypoint} (${this.node.path})`.slice(0, 256),
@@ -210,6 +219,7 @@ export class Provider extends CoreConstruct implements ICustomResourceProvider {
       vpcSubnets: this.vpcSubnets,
       securityGroups: this.securityGroups,
       role: this.role,
+      functionName: name,
     });
 
     fn.addEnvironment(consts.USER_ON_EVENT_FUNCTION_ARN_ENV, this.onEventHandler.functionArn);

packages/@aws-cdk/custom-resources/test/provider-framework/provider.test.ts

@@ -397,3 +397,27 @@ describe('role', () => {
     });
   });
 });
+
+describe('name', () => {
+  it('uses custom name when present', () => {
+    // GIVEN
+    const stack = new Stack();
+    const providerFunctionName = 'test-name';
+
+    // WHEN
+    new cr.Provider(stack, 'MyProvider', {
+      onEventHandler: new lambda.Function(stack, 'MyHandler', {
+        code: lambda.Code.fromAsset(path.join(__dirname, './integration-test-fixtures/s3-file-handler')),
+        handler: 'index.onEvent',
+        runtime: lambda.Runtime.NODEJS_10_X,
+      }),
+      providerFunctionName,
+    });
+
+    // THEN
+    expect(stack).toHaveResourceLike('AWS::Lambda::Function', {
+      FunctionName: providerFunctionName,
+    });
+  });
+});
+