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# (c) 2014, Brian Coca, Josh Drake, et al
# (c) 2017 Ansible Project
# GNU General Public License v3.0+ (see COPYING or https://www.gnu.org/licenses/gpl-3.0.txt)
'''
DOCUMENTATION:
cache: redis
short_description: Use Redis DB for cache
description:
- This cache uses JSON formatted, per host records saved in Redis.
version_added: "1.9"
requirements:
- redis (python lib)
options:
_uri:
description:
- A colon separated string of connection information for Redis.
required: True
env:
- name: ANSIBLE_CACHE_PLUGIN_CONNECTION
ini:
- key: fact_caching_connection
section: defaults
_prefix:
description: User defined prefix to use when creating the DB entries
env:
- name: ANSIBLE_CACHE_PLUGIN_PREFIX
ini:
- key: fact_caching_prefix
- section: defaults
_timeout:
default: 86400
description: Expiration timeout for the cache plugin data
env:
- name: ANSIBLE_CACHE_PLUGIN_TIMEOUT
ini:
- key: fact_caching_timeout
section: defaults
type: integer
'''
from __future__ import (absolute_import, division, print_function)
__metaclass__ = type
import time
import json
from ansible import constants as C
from ansible.errors import AnsibleError
from ansible.plugins.cache import BaseCacheModule
try:
from redis import StrictRedis
except ImportError:
raise AnsibleError("The 'redis' python module is required for the redis fact cache, 'pip install redis'")
class CacheModule(BaseCacheModule):
"""
A caching module backed by redis.
Keys are maintained in a zset with their score being the timestamp
when they are inserted. This allows for the usage of 'zremrangebyscore'
to expire keys. This mechanism is used or a pattern matched 'scan' for
performance.
"""
def __init__(self, *args, **kwargs):
if C.CACHE_PLUGIN_CONNECTION:
connection = C.CACHE_PLUGIN_CONNECTION.split(':')
else:
connection = []
self._timeout = float(C.CACHE_PLUGIN_TIMEOUT)
self._prefix = C.CACHE_PLUGIN_PREFIX
self._cache = {}
self._db = StrictRedis(*connection)
self._keys_set = 'ansible_cache_keys'
def _make_key(self, key):
return self._prefix + key
def get(self, key):
if key not in self._cache:
value = self._db.get(self._make_key(key))
# guard against the key not being removed from the zset;
# this could happen in cases where the timeout value is changed
# between invocations
if value is None:
self.delete(key)
raise KeyError
self._cache[key] = json.loads(value)
return self._cache.get(key)
def set(self, key, value):
value2 = json.dumps(value)
if self._timeout > 0: # a timeout of 0 is handled as meaning 'never expire'
self._db.setex(self._make_key(key), int(self._timeout), value2)
else:
self._db.set(self._make_key(key), value2)
self._db.zadd(self._keys_set, time.time(), key)
self._cache[key] = value
def _expire_keys(self):
if self._timeout > 0:
expiry_age = time.time() - self._timeout
self._db.zremrangebyscore(self._keys_set, 0, expiry_age)
def keys(self):
self._expire_keys()
return self._db.zrange(self._keys_set, 0, -1)
def contains(self, key):
self._expire_keys()
return (self._db.zrank(self._keys_set, key) is not None)
def delete(self, key):
del self.cache[key]
self._db.delete(self._make_key(key))
self._db.zrem(self._keys_set, key)
def flush(self):
for key in self.keys():
self.delete(key)
def copy(self):
# TODO: there is probably a better way to do this in redis
ret = dict()
for key in self.keys():
ret[key] = self.get(key)
return ret
def __getstate__(self):
return dict()
def __setstate__(self, data):
self.__init__()
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