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@svrist
Created February 7, 2017 21:34
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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:])
@dheeraj-thedev
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How Do we use Yaml File in this scenario ?

@illusivedeveloper
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How Do we use Yaml File in this scenario ?

@dheeraj-thedev @AiswaryaGopal

I am also looking for YAML example using boto3, however, I found troposphere which supports Yaml files. An example is given here.

@dheeraj-thedev
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@illusivedeveloper @AiswaryaGopal
https://boto3.amazonaws.com/v1/documentation/api/1.9.42/reference/services/cloudformation.html
I found this on boto3 official documentation that

**validate_template(kwargs)
Validates a specified template. AWS CloudFormation first checks if the template is valid JSON. If it isn't, AWS CloudFormation checks if the template is valid YAML. If both these checks fail, AWS CloudFormation returns a template validation error.

 def _parse_template(template):
        with open(template) as template_fileobj:
        template_data = template_fileobj.read()
        cf.validate_template(TemplateBody=template_data)
        return template_data

@berniedurfee
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Very helpful, thank you!!

@yesgokulcan
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Where to mention our json template file location

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