📊Tracking: migrating CloudFormation templates to the CDK

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Overview:

We want to expand the capabilities of the CfnInclude class from the core package to allow retrieving and modifying the resources that form the template. Example experience:

import * as cfn_inc from '@aws-cdk/cloudformation-include';

const cfnTemplate = new cfn_inc.CfnInclude(this, 'Template', {
  templateFile: 'my-template.json',
});
const cfnBucket = cfnTemplate.getResource('Bucket') as s3.CfnBucket;

// now, we can modify the bucket, and all of those modifications will be reflected in the resulting template!
// for example, we can change its name
cfnBucket.bucketName = 'my-bucket-name';

// or, reference it in other constructs, including L2s
import * as iam from '@aws-cdk/aws-iam';

const role = new iam.Role(this, 'Role', {
  assumedBy: new iam.AnyPrincipal(),
});
role.addToPolicy(new iam.PolicyStatement({
  actions: ['s3:*'],
  resources: [cfnBucket.attrArn],
}));

// or, reference an L2 bucket from the L1
const bucket = s3.Bucket.fromBucketName(this, 'L2Bucket', cfnBucket.ref);

Maturity: Experimental

See the AWS Construct Library Module Lifecycle doc for more information about maturity levels.

Implementation:

• Support YAML templates in addition to JSON ones

• Retrieving Resources by their logical ID

• Retrieving Parameters by their logical ID

• Retrieving Conditions by their logical ID

• Retrieving Outputs by their logical ID

• Support for the Properties CloudFormation resource attribute

• Support for the Condition CloudFormation resource attribute

• Support for the DependsOn CloudFormation resource attribute

• Support for the CreationPolicy CloudFormation resource attribute

• Support for the UpdatePolicy CloudFormation resource attribute

• Support for the UpdateReplacePolicy CloudFormation resource attribute

• Support for the DeletionPolicy CloudFormation resource attribute

• Support for the Metadata CloudFormation resource attribute

• Full support for all CloudFormation functions

• Support nested Stacks

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This is a 📊Tracking Issue

[Lock128]

Thanks for sharing the link, I wasn’t aware of that project. That’s what I was looking for 😉

The cocern I have: it will essentially mean for us to keep the CloudFormation code “forever”…or until we migrate it…and do the enhancements in CDK… which is kind of … weird…because it breaks languages “in the middle” 😃 But its a good starting point, definitely, I was not trying to narrow this down, please don’t understand me wrong.

[Lock128]

Well, no, not exactly. That will most certainly be helpful.

But: We have a hell lot of CloudFormation already, this option would only give us the option to “keep” it and “adjust” it on the fly when using CDK.

If I want to go “all in” on CDK I would need an option to “transform” the CloudFormation code to CDK code (in whatever language).