InterfaceParameterExists.py

"""
Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
SPDX-License-Identifier: MIT-0
"""
from cfnlint.rules import CloudFormationLintRule
from cfnlint.rules import RuleMatch


class InterfaceParameterExists(CloudFormationLintRule):
    """Check if Metadata Interface parameters exist"""

    id = 'W4001'
    shortdesc = 'Metadata Interface parameters exist'
    description = 'Metadata Interface parameters actually exist'
    source_url = 'https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-cloudformation-interface.html'
    tags = ['metadata']

    valid_keys = ['ParameterGroups', 'ParameterLabels']

    def match(self, cfn):
        """Check CloudFormation Metadata Parameters Exist"""

        matches = []

        strinterface = 'AWS::CloudFormation::Interface'
        parameters = cfn.get_parameter_names()
        metadata_obj = cfn.template.get('Metadata', {})
        if metadata_obj:
            interfaces = metadata_obj.get(strinterface, {})
            if isinstance(interfaces, dict):
                # Check Parameter Group Parameters
                paramgroups = interfaces.get('ParameterGroups', [])
                if isinstance(paramgroups, list):
                    for index, value in enumerate(paramgroups):
                        if 'Parameters' in value:
                            for paramindex, paramvalue in enumerate(
                                value['Parameters']
                            ):
                                if paramvalue not in parameters:
                                    message = 'Metadata Interface parameter doesn\'t exist {0}'
                                    matches.append(
                                        RuleMatch(
                                            [
                                                'Metadata',
                                                strinterface,
                                                'ParameterGroups',
                                                index,
                                                'Parameters',
                                                paramindex,
                                            ],
                                            message.format(paramvalue),
                                        )
                                    )
                paramlabels = interfaces.get('ParameterLabels', {})
                if isinstance(paramlabels, dict):
                    for param in paramlabels:
                        if param not in parameters:
                            message = 'Metadata Interface parameter doesn\'t exist {0}'
                            matches.append(
                                RuleMatch(
                                    [
                                        'Metadata',
                                        strinterface,
                                        'ParameterLabels',
                                        param,
                                    ],
                                    message.format(param),
                                )
                            )

        return matches