---  > **This is a stable example. It should successfully build out of the box** > > This example is built on Construct Libraries marked "Stable" and does not have any infrastructure prerequisites to build. --- # CDK Custom Resource Provider Framework Example This sample project demonstrates how to define a custom resource using the @aws-cdk/custom-resource package Provider framework. From the [documentation](https://docs.aws.amazon.com/cdk/api/latest/docs/custom-resources-readme.html): The @aws-cdk/custom-resources.Provider construct is a "mini-framework" for implementing providers for AWS CloudFormation custom resources. The framework offers a high-level API which makes it easier to implement robust and powerful custom resources and includes the following capabilities: * Handles responses to AWS CloudFormation and protects against blocked deployments * Validates handler return values to help with correct handler implementation * Supports asynchronous handlers to enable operations that require a long waiting period for a resource, which can exceed the AWS Lambda timeout Implements default behavior for physical resource IDs This example implements the same stack and 'custom resource' as the [custom resource](../custom-resource) example which itself used deprecated CustomResource and CustomResourceProvider from the @aws-cdk/aws-cloudformation package. ## Build To build this app, you need to be in this example's root folder. Then run the following: ```bash npm install -g aws-cdk npm install npm run build ``` This will install the necessary CDK, then this example's dependencies, and then build your TypeScript files and your CloudFormation template. ## Deployment This stack uses assets, so the [toolkit stack must be deployed to the environment](https://docs.aws.amazon.com/cdk/latest/guide/bootstrapping.html). This can be done by running the following command: ```bash cdk bootstrap ``` At this point you can now synthesize the CloudFormation template for this code: ```bash cdk synth ``` And proceed to deployment of the stack: ```bash cdk deploy ``` ## Important files | Filename | Purpose | Notes | | ------------------------------------------------------------------------------------------ | ------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [cdk.json](cdk.json) | CDK app definition file | The `cdk.json` file tells the CDK Toolkit how to execute your app. | | [my-custom-resource-provider-demo-stack.ts](lib/my-custom-resource-provider-demo-stack.ts) | The stack definition | This is an exact copy of the example provided in [custom-resource](../custom-resource/index.ts) | | [my-custom-resource.ts](lib/my-custom-resource.ts) | A construct that encapsulates the custom resource | This is an implementation from the [provider framework](https://docs.aws.amazon.com/cdk/api/latest/docs/custom-resources-readme.html#provider-framework) documentation. | | [custom-resource-handler.py](custom-resource-handler.py) | The Lambda function definition of the custom provider handler | From the [provider framework](https://docs.aws.amazon.com/cdk/api/latest/docs/custom-resources-readme.html#provider-framework) documentation. | ## Useful commands * `npm run build` compile typescript to js * `npm run watch` watch for changes and compile * `npm run test` perform the jest unit tests * `cdk deploy` deploy this stack to your default AWS account/region * `cdk diff` compare deployed stack with current state * `cdk synth` emits the synthesized CloudFormation template