starter script to use boto / aws API to deploy a cloudformation script

deploy_cf_script.py

import os
import time
import boto3
from botocore.exceptions import ClientError

def get_api_id_from_stack(stack_name):
	api_id = ""

	try:
		cloudformation = boto3.client('cloudformation')
		resp = cloudformation.describe_stack_resources(StackName=stack_name)

		for r in resp['StackResources']:
			if r['ResourceType'] == "AWS::ApiGateway::RestApi":
				api_id = r['PhysicalResourceId']
				break

	except:
		print 'missing api name'

	return api_id


def deploy_api_to_stage(env, stack_name):
	api_id = get_api_id_from_stack(stack_name)


def get_stack_details(stack_name):
	stack_response = None

	try:
		client = boto3.client('cloudformation')
		stack_response = client.describe_stacks(StackName=stack_name)
	except ClientError, e:
		# {'response': {'ResponseMetadata': {'HTTPStatusCode': 400, 'RequestId': '0260b50f-1140-11e6-afe2-6d45d439b6fc'}, 
		#               'Error': {'Message': 'Stack with id cfcareers-chriscfX does not exist', 'Code': 'ValidationError', 'Type': 'Sender'}}}
		if e.response['Error']['Message'].find("does not exist"):
			print 'stack {0} not found...'.format(stack_name)
		else:
			raise
	else:
		stack_arn = stack_response['Stacks'][0]['StackId']
		print stack_arn

	return stack_response['Stacks'][0]


def deploy_cloudformation_script(env, stack_name, template_body, cf_parameters):
	client = boto3.client('cloudformation')
	stack_arn = ""

	stack_details = get_stack_details(stack_name)
	if stack_details:
		stack_arn = stack_details['StackId']

	if stack_details['StackStatus'] in ['CREATE_IN_PROGRESS', 'UPDATE_IN_PROGRESS']:
		print 'stack is currently being created/updated...'
		return
	
	if len(stack_arn) > 0:
		try:
			print 'updating stack...'
			resp = client.update_stack(StackName=stack_name, 
									   TemplateBody=template_body, 
									   Parameters=cf_parameters, 
									   Capabilities=['CAPABILITY_IAM'],
									   Tags=[{'Key': 'environment', 'Value': env}])
		except ClientError, e:
			if e.response['Error']['Message'] == "No updates are to be performed.":
				print('No updates are to be performed')
			else:
				raise	
	else:
		try:
			print 'creating stack...'
			resp = client.create_stack(StackName=stack_name, 
									   TemplateBody=template_body, 
									   Parameters=cf_parameters, 
									   Capabilities=['CAPABILITY_IAM'],
									   Tags=[{'Key': 'environment', 'Value': env}])
			print resp
		except ClientError, e:
			if e.response['Error']['Message'] == "No updates are to be performed.":
				print('No updates are to be performed')
			else:
				raise	

	while True:
		time.sleep(5)
		stack_details = get_stack_details(stack_name)
		if stack_details:
			#print stack_details
			if stack_details['StackStatus'] in ['CREATE_COMPLETE', 'UPDATE_COMPLETE']:
				print 'stack script completed.'
				break
			elif stack_details['StackStatus'] in ['CREATE_IN_PROGRESS', 'UPDATE_IN_PROGRESS']:
				print 'stack script in progress.'				
			else:
				print 'uh oh. check stack status: '
				break

#__location__ = os.path.realpath(os.path.join(os.getcwd(), os.path.dirname(__file__)))
#f = open(os.path.join(__location__, 'job_search_cf.template'));
f = open('my_cf.template')
template_body = f.read()

env = 'dev'
stack = 'mystackname'

parameters = [{"ParameterKey": "Environment", "ParameterValue": env}]

deploy_cloudformation_script(env, "{0}-{1}".format(stack, env), template_body, parameters)