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#
# (c) 2016 Allen Sanabria, <asanabria@linuxdynasty.org>
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible. If not, see <http://www.gnu.org/licenses/>.
#
"""
This module adds shared support for generic cloud modules
In order to use this module, include it as part of a custom
module as shown below.
from ansible.module_utils.cloud import *
The 'cloud' module provides the following common classes:
* CloudRetry
- The base class to be used by other cloud providers, in order to
provide a backoff/retry decorator based on status codes.
- Example using the AWSRetry class which inherits from CloudRetry.
@AWSRetry.retry(tries=20, delay=2, backoff=2)
get_ec2_security_group_ids_from_names()
"""
from functools import wraps
import syslog
import time
from ansible.module_utils.pycompat24 import get_exception
class CloudRetry(object):
""" CloudRetry can be used by any cloud provider, in order to implement a
backoff algorithm/retry effect based on Status Code from Exceptions.
"""
# This is the base class of the exception.
# AWS Example botocore.exceptions.ClientError
base_class = None
@staticmethod
def status_code_from_exception(error):
""" Return the status code from the exception object
Args:
error (object): The exception itself.
"""
pass
@staticmethod
def found(response_code):
""" Return True if the Response Code to retry on was found.
Args:
response_code (str): This is the Response Code that is being matched against.
"""
pass
@classmethod
def backoff(cls, tries=10, delay=3, backoff=1.1):
""" Retry calling the Cloud decorated function using an exponential backoff.
Kwargs:
tries (int): Number of times to try (not retry) before giving up
default=10
delay (int): Initial delay between retries in seconds
default=3
backoff (int): backoff multiplier e.g. value of 2 will double the delay each retry
default=2
"""
def deco(f):
@wraps(f)
def retry_func(*args, **kwargs):
max_tries, max_delay = tries, delay
while max_tries > 1:
try:
return f(*args, **kwargs)
except Exception:
e = get_exception()
if isinstance(e, cls.base_class):
response_code = cls.status_code_from_exception(e)
if cls.found(response_code):
msg = "{0}: Retrying in {1} seconds...".format(str(e), max_delay)
syslog.syslog(syslog.LOG_INFO, msg)
time.sleep(max_delay)
max_tries -= 1
max_delay *= backoff
else:
# Return original exception if exception is not a ClientError
raise e
else:
# Return original exception if exception is not a ClientError
raise e
return f(*args, **kwargs)
return retry_func # true decorator
return deco
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