@nrfcloud/cdktf-aws-adaptor

A compatibility layer for using the CDK for Terraform with AWS CDK constructs

$3

The CDK for Terraform is a great tool for managing infrastructure, but it lacks the ecosystem of constructs that the AWS CDK has.
This tool allows you to use the excellent aws-cdk-lib construct library, while also getting access to the benefits of terraform.
Think of provisioning a CockroachDB cloud cluster and connecting it to a lambda using the high level nodejs function construct in the same stack.

#### But isn't there already an adaptor?
Yes, but it's in technical preview and missing many essential features.
It also doesn't seem to be actively maintained.

$3

* Bidirectional references between AWS CDK and CDK for Terraform constructs
* Interstack referencing
* Dependency ordering compatibility
* Cloudformation intrinsics
* Assets

#### Caveats
* References to AWS CDK constructs only work within the scope of adaptor classes
* AWS CDK aspects are not supported
* Custom resources are not supported

Basic Usage

Essentially, just use the provided AwsTerraformAdaptorStack class as your base stack class instead of TerraformStack
``typescript
import {AwsTerraformAdaptorStack} from "./cdk-adaptor-stack";
import {Bucket} from "aws-cdk-lib";
import {S3Bucket} from "@cdktf/provider-aws/lib/s3-bucket/index.js";
import {S3BucketObject} from "@cdktf/provider-aws/lib/s3-bucket-object";

class MyStack extends AwsTerraformAdaptorStack {
constructor(scope: Construct, id: string, region: string) {
super(scope, id, region);

// You can instantiate AWS CDK constructs as normal
const bucket = new Bucket(this, 'MyBucket', {
bucket: 'my-bucket',
});

// You can also instantiate CDK for Terraform constructs
// Bidirectional references between the two are automatically created
const tfBucket = new S3BucketObject(this, 'MyTfBucket', {
bucket: bucket.bucketName,
key: 'my-tf-bucket',
source: 'my-tf-bucket',
});
}
}
`

Compatibility

Internally, the adaptor tries to use the CloudControl api for 1-1 compatibility with Cloudformation.
In some cases this is enough, but in many others explicit resource mappings are required.
The adaptor ships with a good variety of these mappings, but it is not exhaustive.

If you encounter an error like No resource mapping found for , you can add a mapping for it like so:
`typescript
// Map between a L1 Cloudformation construct and a CDK for Terraform construct
registerMappingTyped(CfnBucketPolicy, S3BucketPolicy, {
resource(scope, id, props) {
return new S3BucketPolicy(
scope,
id,
deleteUndefinedKeys({
// ALL keys of the provided construct must be mapped
policy: Fn.jsonencode(props.PolicyDocument),
bucket: props.Bucket,
}),
);
},
attributes: {
// ALL attributes of the provided construct must be mapped
Ref: (resource) => resource.id,
},
});
``

$3

The Cloudcontrol api is theoretically a stable crud API 1-1 with cloudformation, but it in practice it has some quirks.
Update operations in particular seems to break with alarming regularity, so explicit mappings are preferred, especially for complex resources.