| """ |
| Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. |
| SPDX-License-Identifier: MIT-0 |
| """ |
|
|
| from cfnlint._typing import RuleMatches |
| from cfnlint.rules import CloudFormationLintRule, RuleMatch |
| from cfnlint.template import Template |
|
|
|
|
| class CircularDependency(CloudFormationLintRule): |
| """Check if Resources have a circular dependency""" |
|
|
| id = "E3004" |
| shortdesc = "Resource dependencies are not circular" |
| description = ( |
| "Check that Resources are not circularly dependent by DependsOn, Ref, Sub, or" |
| " GetAtt" |
| ) |
| source_url = "https://github.com/aws-cloudformation/cfn-lint" |
| tags = ["resources", "circularly", "dependson", "ref", "sub", "getatt"] |
|
|
| def match(self, cfn: Template) -> RuleMatches: |
| matches = [] |
|
|
| if cfn.graph is None: |
| return [] |
| for cycle in cfn.graph.get_cycles(cfn): |
| source, target = cycle[:2] |
| if ( |
| cfn.graph.graph.nodes[source].get("type") == "Resource" |
| and cfn.graph.graph.nodes[target].get("type") == "Resource" |
| ): |
| message = ( |
| f"Circular Dependencies for resource {source}. Circular dependency" |
| f" with [{target}]" |
| ) |
| path = ["Resources", source] |
| matches.append(RuleMatch(path, message)) |
|
|
| return matches |
|
|
