CloudFormation Resource Spec...issues?

resourcespec.md

When I started troposphere there wasn't a resource specification formally defining the various resource and properties for CloudFormation.

The resource spec came out and it's been interesting to see it evolve. For a project like troposphere, it is sorely needed to ensure correctly reflecting the CloudFormation constrects into code (Python for troposphere). This allowed resources and properties to be auto-generated and have better accuracy.

But recently I've seen some odd usage patterns being used with it which I don't believe are correct. Below is some commentary on it.

Isssue: properties without Properties

#!/usr/bin/env python3

import json


# CloudFormation resource specification file
filename = "CloudFormationResourceSpecification.json"


def find_no_properties(spec):
    props = []
    for p, d in spec['PropertyTypes'].items():
        if 'Properties' not in d:
            props.append(p)
    print('\n'.join(sorted(props)))

if __name__ == "__main__":
    # read in the resource spec
    spec = json.loads(open(filename).read())
    find_no_properties(spec)

AWS::AppSync::GraphQLApi.AdditionalAuthenticationProviders
AWS::AppSync::GraphQLApi.Tags
AWS::CodeBuild::Project.FilterGroup
AWS::EC2::LaunchTemplate.CapacityReservationPreference
AWS::Glue::SecurityConfiguration.S3Encryptions
AWS::LakeFormation::DataLakeSettings.Admins
AWS::Transfer::User.SshPublicKey
AWS::WAFv2::RuleGroup.AllQueryArguments
AWS::WAFv2::RuleGroup.AllowAction
AWS::WAFv2::RuleGroup.BlockAction
AWS::WAFv2::RuleGroup.Body
AWS::WAFv2::RuleGroup.CountAction
AWS::WAFv2::RuleGroup.Method
AWS::WAFv2::RuleGroup.QueryString
AWS::WAFv2::RuleGroup.UriPath
AWS::WAFv2::WebACL.AllQueryArguments
AWS::WAFv2::WebACL.AllowAction
AWS::WAFv2::WebACL.BlockAction
AWS::WAFv2::WebACL.Body
AWS::WAFv2::WebACL.CountAction
AWS::WAFv2::WebACL.Method
AWS::WAFv2::WebACL.NoneAction
AWS::WAFv2::WebACL.QueryString
AWS::WAFv2::WebACL.UriPath

Let's look at a couple of these via the individual files:

$ cat spec/LakeFormationDataLakeSettingsSpecification.json
{
  "PropertyTypes": {
    "AWS::LakeFormation::DataLakeSettings.Admins": {
      "Type": "List",
      "Required": false,
      "Documentation": "http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-lakeformation-datalakesettings-admins.html",
      "ItemType": "DataLakePrincipal",
      "UpdateType": "Mutable"
    },
    "AWS::LakeFormation::DataLakeSettings.DataLakePrincipal": {
      "Documentation": "http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-lakeformation-datalakesettings-datalakeprincipal.html",
      "Properties": {
        "DataLakePrincipalIdentifier": {
          "Required": false,
          "Documentation": "http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-lakeformation-datalakesettings-datalakeprincipal.html#cfn-lakeformation-datalakesettings-datalakeprincipal-datalakeprincipalidentifier",
          "PrimitiveType": "String",
          "UpdateType": "Mutable"
        }
      }
    }
  },
  "ResourceType": {
    "AWS::LakeFormation::DataLakeSettings": {
      "Documentation": "http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-lakeformation-datalakesettings.html",
      "Properties": {
        "Admins": {
          "Type": "Admins",
          "Required": false,
          "Documentation": "http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-lakeformation-datalakesettings.html#cfn-lakeformation-datalakesettings-admins",
          "UpdateType": "Mutable"
        }
      }
    }
  },
  "ResourceSpecificationVersion": "9.1.1"
}

Here we have DataLakeSettings defining a Property (Admins) which is of type 'Admins'. This Property is then defined as a List of DataLakePrincipal. Why is there an intermediate Admins Propery? Why isn't "Admins" just defined as a List of DataLakePrincipal?

Issue: Empty Property

{
  "PropertyTypes": {
    "AWS::WAFv2::WebACL.AllowAction": {
      "Documentation": "http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-wafv2-webacl-allowaction.html"
    },
    "AWS::WAFv2::WebACL.BlockAction": {
      "Documentation": "http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-wafv2-webacl-blockaction.html"
    },

Here we have WAFv2 properties being defined only as "Documentation". Why???

Issue: Tags