LambdaMemorySize.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 LambdaMemorySize(CloudFormationLintRule):
    """Check Lambda Memory Size """
    id = 'W2510'
    shortdesc = 'Parameter Memory Size attributes should have max and min'
    description = 'Check if a parameter that is used for Lambda memory size ' \
                  ' should have a min and max size that matches Lambda constraints'
    source_url = 'https://docs.aws.amazon.com/lambda/latest/dg/API_CreateFunction.html#SSS-CreateFunction-request-MemorySize'
    tags = ['parameters', 'lambda']

    def __init__(self):
        """Init"""
        super(LambdaMemorySize, self).__init__()
        resource_type_specs = [
            'AWS::Lambda::Function',
        ]

        for resource_type_spec in resource_type_specs:
            self.resource_property_types.append(resource_type_spec)

    # pylint: disable=W0613
    def check_lambda_memory_size_ref(self, value, path, parameters, resources):
        matches = []

        if value in parameters:
            parameter = parameters.get(value)
            min_value = parameter.get('MinValue')
            max_value = parameter.get('MaxValue')
            allowed_values = parameter.get('AllowedValues')
            if (not min_value or not max_value) and (not allowed_values):
                param_path = ['Parameters', value]
                message = 'Lambda Memory Size parameters should use MinValue, MaxValue ' \
                          'or AllowedValues at {0}'
                matches.append(
                    RuleMatch(
                        param_path,
                        message.format(('/'.join(param_path)))))

        return matches

    def check(self, properties, resource_type, path, cfn):
        """Check itself"""
        matches = []

        matches.extend(
            cfn.check_value(
                properties, 'MemorySize', path,
                check_value=None, check_ref=self.check_lambda_memory_size_ref,
                check_find_in_map=None, check_split=None, check_join=None
            )
        )

        return matches

    def match_resource_properties(self, properties, resource_type, path, cfn):
        """Check CloudFormation Properties"""
        matches = []

        matches.extend(self.check(properties, resource_type, path, cfn))

        return matches