The cfnlint package is an AWS CloudFormation linter that uses the [AWS CloudFormation Resource Specification](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/cfn-resource-specification.html) and is customizable and extendible with a custom ruleset.
A custom ruleset is optional and adds the following features:
- Specify supported Resources: Block the specification of specific Resources
- Override required Properties: Make non-required properties required to enforce the specification of Properties
- Enumerators: Specify a list of allowed values to enforce Property values to a set of 1 or more values.
Current version is work in progress and only supported a minimal set of features:
- Current version only support yaml CloudFormation files
- Commandline support available (cfn-lint --help)