cdk-from-cfn

cdk-from-cfn is a command-line tool that converts AWS CloudFormation templates into AWS CDK code. It supports multiple programming languages including TypeScript, Python, Java, Go, and C#.

Installation

cargo install cdk-from-cfn

Usage

cdk-from-cfn [INPUT] [OUTPUT] --language <LANGUAGE> --stack-name <STACK_NAME> [--as <stack|construct>]

• INPUT is the input file path (STDIN by default).
• OUTPUT is the output file path; if not specified, output will be printed on your command line (STDOUT by default).
• --as (optional) specifies the output type: stack (default) or construct. Use construct to generate a reusable CDK construct instead of a standalone stack.

Class Type Option

By default, cdk-from-cfn generates code that extends Stack. You can use the --as flag to generate a reusable Construct instead:

# Generate a Stack (default)
cdk-from-cfn template.json --language typescript --as stack

# Generate a Construct
cdk-from-cfn template.json --language typescript --as construct

When using construct mode:

• The generated class extends Construct instead of Stack
• Props interface does not extend StackProps
• Pseudo-parameters like AWS::StackName use Stack.of(this) to access the parent stack

Node.js Module Usage

cdk-from-cfn leverages WebAssembly (WASM) bindings to provide a cross-platform npm module, which exposes apis to be used in Node.js projects. Simply take a dependency on cdk-from-cfn in your package.json and utilize it as you would a normal module. i.e.

import * as cdk_from_cfn from 'cdk-from-cfn';

// get supported languages
cdk_from_cfn.supported_languages();

// transmute cfn template into cdk app (generates a Stack by default)
cdk_from_cfn.transmute(template, language, stackName);

// transmute cfn template into a reusable Construct
cdk_from_cfn.transmute(template, language, stackName, 'construct');

The transmute function accepts an optional fourth parameter classType:

• 'stack' (default): generates code extending Stack
• 'construct': generates code extending Construct

Language and Feature support

Name	Enabled by default	Description
typescript	✔️	Enables support for TypeScript output
golang	✔️	Enables support for Go output
java	✔️	Enables support for Java output
Python	✔️	Enables support for Python output
csharp	✔️	Enables support for C# output

You can enable experimental languages (not enabled by default) by enabling the relevant feature:

$ cargo build --release --features=<feature-name>
Finished release [optimized] target(s) in 0.17s

If you want to disable on-by-default languages, you can pass --no-default-features:

$ cargo build --release --no-default-features --features=golang
Finished release [optimized] target(s) in 0.17s

Implemented

• Fn::FindInMap
• Fn::Join
• Fn::Sub
• Ref
• Fn::And
• Fn::Equals
• Fn::If
• Fn::Not
• Fn::Or
• Fn::GetAtt
• Fn::Base64 support
• Fn::ImportValue support
• Fn::Select support
• Resource ordering based on dependencies
• Conditions are emitted in ts but not attached to resource conditions
• Metadata emission for updates to asgs / lambda functions.
• Emission of outputs / exports
• Fn::GetAZs support
• Adding depends-on, and ordering based on it too.
• Deletion policy
• Fn::Cidr support

Remaining

There are known unsupported features. Working on them in priority order:

• Create policy
• ssm metadata references
• secretsmanager references