def test_flatten():
"""Ensure flatten method can really flatten an array"""
input_arr = [1, 2, [3, 4], [5, 6, 7]]
output_arr = utils.flatten(input_arr)
assert output_arr == range(1, 8)
def create_or_update_stack(aws_account, region, ebs_bucket_name):
"""Handle creating or updating the ebs-snapper stack, and waiting"""
# check for stack, create it if necessary
stack_name = 'ebs-snapper-{}'.format(aws_account)
cf_client = boto3.client('cloudformation', region_name=region)
template_url = "https://s3.amazonaws.com/{}/cloudformation.json".format(
ebs_bucket_name)
try:
LOG.info('Creating stack from %s', template_url)
# only required parameter
DEFAULT_STACK_PARAMS.append({
'ParameterKey': 'LambdaS3Bucket',
'ParameterValue': ebs_bucket_name,
'UsePreviousValue': False
})
response = cf_client.create_stack(StackName=stack_name,
TemplateURL=template_url,
Parameters=DEFAULT_STACK_PARAMS,
Capabilities=[
'CAPABILITY_IAM',
])
LOG.debug(response)
LOG.warn("Wait while the stack %s is created.", stack_name)
except ClientError as e:
if not e.response['Error']['Code'] == 'AlreadyExistsException':
raise
try:
LOG.info('Stack exists, updating stack from %s', template_url)
# we can't specify "UsePreviousValue" if template didn't have this
# param before our update. We can only UsePreviousValue if param
# is already present in previous version of this template.
sn = stack_name
sr = cf_client.describe_stacks(StackName=sn)
es_stack = [
x for x in sr.get('Stacks', []) if x['StackName'] == sn
]
es_params = [x.get('Parameters', []) for x in es_stack]
es_param_keys = [
x['ParameterKey'] for x in utils.flatten(es_params)
]
# else we will get the default template value for this param
params = []
for k in es_param_keys:
params.append({'ParameterKey': k, 'UsePreviousValue': True})
response = cf_client.update_stack(StackName=stack_name,
TemplateURL=template_url,
Parameters=params,
Capabilities=[
'CAPABILITY_IAM',
])
LOG.debug(response)
LOG.warn("Waiting while the stack %s is being updated.",
stack_name)
except ClientError as f:
validation_error = f.response['Error']['Code'] == 'ValidationError'
no_updates = f.response['Error'][
'Message'] == 'No updates are to be performed.'
if not validation_error and not no_updates:
raise
LOG.warn('No changes. Stack was not updated.')
# wait for stack to settle to a completed status
wait_for_completion(cf_client, stack_name)