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Update or create a CloudFormation stack given a name and template + params'
'Update or create a stack given a name and template + params'
from __future__ import division, print_function, unicode_literals
from datetime import datetime
import logging
import json
import sys
import boto3
import botocore
cf = boto3.client('cloudformation') # pylint: disable=C0103
log = logging.getLogger('deploy.cf.create_or_update') # pylint: disable=C0103
def main(stack_name, template, parameters):
'Update or create stack'
template_data = _parse_template(template)
parameter_data = _parse_parameters(parameters)
params = {
'StackName': stack_name,
'TemplateBody': template_data,
'Parameters': parameter_data,
}
try:
if _stack_exists(stack_name):
print('Updating {}'.format(stack_name))
stack_result = cf.update_stack(**params)
waiter = cf.get_waiter('stack_update_complete')
else:
print('Creating {}'.format(stack_name))
stack_result = cf.create_stack(**params)
waiter = cf.get_waiter('stack_create_complete')
print("...waiting for stack to be ready...")
waiter.wait(StackName=stack_name)
except botocore.exceptions.ClientError as ex:
error_message = ex.response['Error']['Message']
if error_message == 'No updates are to be performed.':
print("No changes")
else:
raise
else:
print(json.dumps(
cf.describe_stacks(StackName=stack_result['StackId']),
indent=2,
default=json_serial
))
def _parse_template(template):
with open(template) as template_fileobj:
template_data = template_fileobj.read()
cf.validate_template(TemplateBody=template_data)
return template_data
def _parse_parameters(parameters):
with open(parameters) as parameter_fileobj:
parameter_data = json.load(parameter_fileobj)
return parameter_data
def _stack_exists(stack_name):
stacks = cf.list_stacks()['StackSummaries']
for stack in stacks:
if stack['StackStatus'] == 'DELETE_COMPLETE':
continue
if stack_name == stack['StackName']:
return True
return False
def json_serial(obj):
"""JSON serializer for objects not serializable by default json code"""
if isinstance(obj, datetime):
serial = obj.isoformat()
return serial
raise TypeError("Type not serializable")
if __name__ == '__main__':
main(*sys.argv[1:])
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