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rule_util.py
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123 lines (99 loc) · 4.66 KB
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import json
import datetime
import boto3
# USE ENTIRE FILE AS IS
aws_config = boto3.client('config')
# Helper function used to validate input
def check_defined(reference, reference_name):
if not reference:
raise Exception('Error: ', reference_name, 'is not defined')
return reference
# Check whether the message is OversizedConfigurationItemChangeNotification
def is_oversized_changed_notification(message_type):
check_defined(message_type, 'messageType')
return message_type == 'OversizedConfigurationItemChangeNotification'
# Get configurationItem using getResourceConfigHistory API.
# In case of OversizedConfigurationItemChangeNotification
def get_configuration(resource_type, resource_id, configuration_capture_time):
result = aws_config.get_resource_config_history(
resourceType=resource_type,
resourceId=resource_id,
laterTime=configuration_capture_time,
limit=1)
configuration_item = result['configurationItems'][0]
return convert_api_configuration(configuration_item)
# Convert from the API model to the original invocation model
def convert_api_configuration(configuration_item):
for k, v in configuration_item.items():
if isinstance(v, datetime.datetime):
configuration_item[k] = str(v)
configuration_item['awsAccountId'] = configuration_item['accountId']
configuration_item['ARN'] = configuration_item['arn']
configuration_item['configurationStateMd5Hash'] = \
configuration_item['configurationItemMD5Hash']
configuration_item['configurationItemVersion'] = \
configuration_item['version']
configuration_item['configuration'] = \
json.loads(configuration_item['configuration'])
if 'relationships' in configuration_item:
for i in range(len(configuration_item['relationships'])):
configuration_item['relationships'][i]['name'] = \
configuration_item['relationships'][i]['relationshipName']
return configuration_item
# Based on the type of message get the configuration item either from
# configurationItem in the invoking event or using the
# getResourceConfigHistory API in getConfiguration function.
def get_configuration_item(invoking_event):
check_defined(invoking_event, 'invoking_event')
if is_oversized_changed_notification(invoking_event['messageType']):
configuration_item_summary = check_defined(
invoking_event['configurationItemSummary'],
'configurationItemSummary')
return get_configuration(
configuration_item_summary['resourceType'],
configuration_item_summary['resourceId'],
configuration_item_summary['configurationItemCaptureTime'])
else:
return check_defined(
invoking_event['configurationItem'],
'configurationItem')
# Check whether the resource has been deleted.
# If it has, then the evaluation is unnecessary.
def is_applicable(configuration_item, event):
check_defined(configuration_item, 'configurationItem')
check_defined(event, 'event')
status = configuration_item['configurationItemStatus']
event_left_scope = event['eventLeftScope']
return (status == 'OK' or status == 'ResourceDiscovered') \
and event_left_scope is False
# This decorates the lambda_handler in rule_code with the
# actual PutEvaluation call
def rule_handler(lambda_handler):
def handler_wrapper(event, context):
check_defined(event, 'event')
invoking_event = json.loads(event['invokingEvent'])
rule_parameters = {}
if 'ruleParameters' in event:
rule_parameters = json.loads(event['ruleParameters'])
configuration_item = get_configuration_item(invoking_event)
invoking_event['configurationItem'] = configuration_item
event['invokingEvent'] = json.dumps(invoking_event)
compliance = 'NOT_APPLICABLE'
if is_applicable(configuration_item, event):
# Invoke the compliance checking function.
compliance = lambda_handler(event, context)
# Put together the request that reports the evaluation status
evaluations = [{
'ComplianceResourceType': configuration_item['resourceType'],
'ComplianceResourceId': configuration_item['resourceId'],
'ComplianceType': compliance,
'OrderingTimestamp':
configuration_item['configurationItemCaptureTime']
}]
result_token = event['resultToken']
# Invoke the Config API to report the result of the evaluation
aws_config.put_evaluations(
Evaluations=evaluations,
ResultToken=result_token)
return compliance
return handler_wrapper