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Bugfix: Allow comments and new lines in custom rules file (#2757)
* 🐛 Add a check for comments and new lines in custom rules In the documentation, comments are allowed to start with `#`. Currently, cfn-lint throws an error of `not in supported operators` which means the comment is being parsed as a custom error. This is now fixed to allow any amount of comments anywhere in the custom rules file. New lines are now allowed just for readability. Currently, cfn-lint throws a traceback error of `UnboundLocalError: cannot access local variable 'operator' where it is not associated with a value` which is not an intuitive error message just for a blank new line. This is now fixed to allow new lines anywhere in the custom rules file. * ✅ Add unit tests for comments and whitespace in custom rules. * ✏️ Update docs for custom rules to allow new lines and comments.
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‎docs/custom_rules.md

+3-3
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@@ -13,7 +13,8 @@ The template used for each custom rules have been included below. Angle brackets
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* The ruleID is auto-generated based on the line number. The E9XXX and W9XXX blocks are allocated towards custom rules.
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* As an example, custom rule on line 4 of the rules file which has error level “ERROR” would become E9004
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* Comments are supported through the use of the # symbol at the beginning of a line (e.g `#This is a comment`)
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* Comments are supported through the use of the # symbol at the beginning of a line (e.g `# This is a comment`)
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* New lines are supported throughout the rules file
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* The syntax is "quote-flexible" and will support all permutations shown below
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```
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AWS::EC2::Instance Property EQUALS "Cloud Formation"
@@ -69,6 +70,7 @@ Pre-Requisites: The Custom Error Message requires an error level to be specified
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A custom error message can be used to override the existing fallback messages. (e.g `Show me this custom message`)
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## Example
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This following example shows how a you can create a custom rule.
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This rule validates all EC2 instances in a template aren’t using the instance type “p3.2xlarge”.
@@ -84,5 +86,3 @@ AWS::Lambda::Function Environment.Variables.NODE_ENV IS DEFINED
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```
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To include this rules, include your custom rules text file using the `-z custom_rules.txt` argument when running cfn-lint.
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‎src/cfnlint/rules/custom/__init__.py

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@@ -42,73 +42,79 @@ def process_sets(raw_value):
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return raw_value
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line = line.rstrip()
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rule_id = lineNumber + 9000
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line = line.split(" ", 3)
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error_level = "E"
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if len(line) == 4:
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resourceType = line[0]
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prop = line[1]
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operator = line[2]
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value = None
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error_message = None
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if "WARN" in line[3]:
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error_level = "W"
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value, error_message = set_arguments(line[3], "WARN")
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elif "ERROR" in line[3]:
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error_level = "E"
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value, error_message = set_arguments(line[3], "ERROR")
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else:
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value = process_sets(line[3])
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value = get_value(line[3])
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# check line is not a comment or empty line
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if not line.startswith("#") and line != "":
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rule_id = lineNumber + 9000
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line = line.split(" ", 3)
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error_level = "E"
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if len(line) == 4:
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resourceType = line[0]
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prop = line[1]
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operator = line[2]
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value = None
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error_message = None
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if "WARN" in line[3]:
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error_level = "W"
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value, error_message = set_arguments(line[3], "WARN")
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elif "ERROR" in line[3]:
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error_level = "E"
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value, error_message = set_arguments(line[3], "ERROR")
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else:
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value = process_sets(line[3])
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value = get_value(line[3])
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if isinstance(value, str):
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value = value.strip().strip('"')
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if isinstance(value, str):
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value = value.strip().strip('"')
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if operator in ["EQUALS", "=="]:
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return cfnlint.rules.custom.Operators.CreateEqualsRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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if operator in ["NOT_EQUALS", "!="]:
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return cfnlint.rules.custom.Operators.CreateNotEqualsRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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if operator == "REGEX_MATCH":
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return cfnlint.rules.custom.Operators.CreateRegexMatchRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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if operator == "IN":
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return cfnlint.rules.custom.Operators.CreateInSetRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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if operator == "NOT_IN":
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return cfnlint.rules.custom.Operators.CreateNotInSetRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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if operator == ">":
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return cfnlint.rules.custom.Operators.CreateGreaterRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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if operator == ">=":
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return cfnlint.rules.custom.Operators.CreateGreaterEqualRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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if operator == "<":
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return cfnlint.rules.custom.Operators.CreateLesserRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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if operator == "<=":
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return cfnlint.rules.custom.Operators.CreateLesserEqualRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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if operator == "IS":
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if value in ["DEFINED", "NOT_DEFINED"]:
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return cfnlint.rules.custom.Operators.CreateCustomIsDefinedRule(
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if operator in ["EQUALS", "=="]:
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return cfnlint.rules.custom.Operators.CreateEqualsRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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if operator in ["NOT_EQUALS", "!="]:
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return cfnlint.rules.custom.Operators.CreateNotEqualsRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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if operator == "REGEX_MATCH":
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return cfnlint.rules.custom.Operators.CreateRegexMatchRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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if operator == "IN":
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return cfnlint.rules.custom.Operators.CreateInSetRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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if operator == "NOT_IN":
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return cfnlint.rules.custom.Operators.CreateNotInSetRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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return cfnlint.rules.custom.Operators.CreateInvalidRule(
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"E" + str(rule_id), f"{operator} {value}"
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)
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if operator == ">":
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return cfnlint.rules.custom.Operators.CreateGreaterRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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if operator == ">=":
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return cfnlint.rules.custom.Operators.CreateGreaterEqualRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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if operator == "<":
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return cfnlint.rules.custom.Operators.CreateLesserRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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if operator == "<=":
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return cfnlint.rules.custom.Operators.CreateLesserEqualRule(
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error_level + str(rule_id), resourceType, prop, value, error_message
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)
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if operator == "IS":
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if value in ["DEFINED", "NOT_DEFINED"]:
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return cfnlint.rules.custom.Operators.CreateCustomIsDefinedRule(
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error_level + str(rule_id),
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resourceType,
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prop,
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value,
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error_message,
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)
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return cfnlint.rules.custom.Operators.CreateInvalidRule(
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"E" + str(rule_id), f"{operator} {value}"
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)
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return cfnlint.rules.custom.Operators.CreateInvalidRule(
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"E" + str(rule_id), operator
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)
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return cfnlint.rules.custom.Operators.CreateInvalidRule(
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"E" + str(rule_id), operator
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)

‎test/fixtures/custom_rules/good/custom_rule_perfect.txt

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@@ -1,3 +1,4 @@
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#This is a comment to ensure comments in custom rules work
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AWS::IAM::Role AssumeRolePolicyDocument.Version EQUALS "2012-10-17"
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AWS::IAM::Role AssumeRolePolicyDocument.Version IN [2012-10-16,2012-10-17,2012-10-18]
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AWS::IAM::Role AssumeRolePolicyDocument.Version NOT_EQUALS "2012-10-15"
@@ -6,10 +7,12 @@ AWS::IAM::Policy PolicyName EQUALS "root" WARN ABC
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AWS::IAM::Policy PolicyName IN [2012-10-16,root,2012-10-18] ERROR ABC
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AWS::IAM::Policy PolicyName NOT_EQUALS "user" WARN ABC
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AWS::IAM::Policy PolicyName NOT_IN [2012-10-16,2012-11-20,2012-10-18] ERROR ABC
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# Adding a comment in the middle of custom rules and new line for readability
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AWS::EC2::Instance BlockDeviceMappings.Ebs.VolumeSize >= 20 WARN
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AWS::EC2::Instance BlockDeviceMappings.Ebs.VolumeSize > 10 ERROR ABC
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AWS::EC2::Instance BlockDeviceMappings.Ebs.VolumeSize <= 50 ERROR DEF
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AWS::EC2::Instance BlockDeviceMappings.Ebs.VolumeSize < 40 WARN ABC
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AWS::CloudFormation::Stack TemplateURL REGEX_MATCH "^https.*$" WARN ABC
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AWS::Lambda::Function Environment.Variables.NODE_ENV IS DEFINED
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AWS::Lambda::Function Environment.Variables.PRIVATE_KEY IS NOT_DEFINED
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AWS::Lambda::Function Environment.Variables.PRIVATE_KEY IS NOT_DEFINED

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