common retry and rate limiting decorators for apis

allows modules to wrap their request functions in common retry and rate limiting
decorators or functions
pull/13339/head
Brian Coca 9 years ago
parent f467f1770f
commit 18e9bc9753

@ -0,0 +1,103 @@
#
# (c) 2015 Brian Ccoa, <bcoca@ansible.com>
#
# 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 api modules
In order to use this module, include it as part of a custom
module as shown below.
** Note: The order of the import statements does matter. **
from ansible.module_utils.basic import *
from ansible.module_utils.api import *
The 'api' module provides the following common argument specs:
* rate limit spec
- rate: number of requests per time unit (int)
- rate_limit: time window in which the limit is applied in seconds
* retry spec
- retries: number of attempts
- retry_pause: delay between attempts in seconds
"""
import time
def rate_limit_argument_spec(spec=None):
"""Creates an argument spec for working with rate limiting"""
arg_spec = (dict(
rate=dict(type='int'),
rate_limit=dict(type='int'),
))
if spec:
arg_spec.update(spec)
return arg_spec
def retry_argument_spec(spec=None):
"""Creates an argument spec for working with retrying"""
arg_spec = (dict(
retries=dict(type='int'),
retry_pause=dict(type='float', default=1),
))
if spec:
arg_spec.update(spec)
return arg_spec
def rate_limit(rate=None, rate_limit=None):
"""rate limiting decorator"""
minrate = None
if rate is not None and rate_limit is not None:
minrate = float(rate_limit) / float(rate)
def wrapper(f):
last = [0.0]
def ratelimited(*args,**kwargs):
if minrate is not None:
elapsed = time.clock() - last[0]
left = minrate - elapsed
if left > 0:
time.sleep(left)
last[0] = time.clock()
ret = f(*args,**kwargs)
return ret
return ratelimited
return wrapper
def retry(retries=None, retry_pause=1):
"""Retry decorator"""
def wrapper(f):
retry_count = 0
def retried(*args,**kwargs):
if retries is not None:
ret = None
while True:
retry_count += 1
if retry_count >= retries:
raise Exception("Retry limit exceeded: %d" % retries)
try:
ret = f(*args,**kwargs)
except:
pass
if ret:
break
time.sleep(retry_pause)
return ret
return retried
return wrapper
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