def cached(timeout, group=None, backend=None, key=None):
""" Caching decorator. Can be applied to function, method or classmethod.
Supports bulk cache invalidation and invalidation for exact parameter
set. Cache keys are human-readable because they are constructed from
callable's full name and arguments and then sanitized to make
memcached happy.
It can be used with or without group_backend. Without group_backend
bulk invalidation is not supported.
Wrapped callable gets `invalidate` methods. Call `invalidate` with
same arguments as function and the result for these arguments will be
invalidated.
"""
if key:
def test(*args, **kwargs):
args = list(args)
args[0] = key
return sanitize_memcached_key(_cache_key(*args, **kwargs))
_get_key = test
else:
_get_key = lambda *args, **kwargs: sanitize_memcached_key(_cache_key(*args, **kwargs))
if group:
backend_kwargs = {'group': group}
else:
backend_kwargs = {}
if backend:
cache_backend = get_cache(backend)
else:
cache_backend = get_cache('default')
def _cached(func):
func_type = _func_type(func)
@wraps(func)
def wrapper(*args, **kwargs):
full_name(*args)
# try to get the value from cache
key = _get_key(wrapper._full_name, func_type, args, kwargs)
value = cache_backend.get(key, **backend_kwargs)
# in case of cache miss recalculate the value and put it to the cache
if value is None:
logger.debug("Cache MISS: %s" % key)
value = func(*args, **kwargs)
cache_backend.set(key, value, timeout, **backend_kwargs)
logger.debug("Cache SET: %s" % key)
else:
logger.debug("Cache HIT: %s" % key)
return value
def invalidate(*args, **kwargs):
"""
Invalidates cache result for function called with passed arguments
"""
if not hasattr(wrapper, '_full_name'):
return
key = _get_key(wrapper._full_name, 'function', args, kwargs)
cache_backend.delete(key, **backend_kwargs)
logger.debug("Cache DELETE: %s" % key)
def force_recalc(*args, **kwargs):
"""
Forces a call to the function & sets the new value in the cache
"""
full_name(*args)
key = _get_key(wrapper._full_name, func_type, args, kwargs)
value = func(*args, **kwargs)
cache_backend.set(key, value, timeout, **backend_kwargs)
return value
def full_name(*args):
# full name is stored as attribute on first call
if not hasattr(wrapper, '_full_name'):
name, _args = _func_info(func, args)
wrapper._full_name = name
def require_cache(*args, **kwargs):
"""
Only pull from cache, do not attempt to calculate
"""
full_name(*args)
key = _get_key(wrapper._full_name, func_type, args, kwargs)
logger.debug("Require cache %s" % key)
value = cache_backend.get(key, **backend_kwargs)
if not value:
logger.info("Could not find required cache %s" % key)
raise NoCachedValueException
return value
def get_cache_key(*args, **kwargs):
""" Returns name of cache key utilized """
full_name(*args)
key = _get_key(wrapper._full_name, 'function', args, kwargs)
return key
wrapper.require_cache = require_cache
wrapper.invalidate = invalidate
wrapper.force_recalc = force_recalc
wrapper.get_cache_key = get_cache_key
return wrapper
return _cached
def test(*args, **kwargs):
args = list(args)
args[0] = key
return sanitize_memcached_key(_cache_key(*args, **kwargs))
def get_key(*args, **kwargs):
return sanitize_memcached_key(_cache_key(*args, **kwargs))
def get_key(self, func_name, func_type, args, kwargs):
self.full_key = key = smart_str(_cache_key(func_name, func_type, args, kwargs))
return sanitize_memcached_key(key)
def test(*args, **kwargs):
args = list(args)
args[0] = key
return sanitize_memcached_key(_cache_key(*args, **kwargs))
def cached(timeout, group=None, backend=None, key=None):
""" Caching decorator. Can be applied to function, method or classmethod.
Supports bulk cache invalidation and invalidation for exact parameter
set. Cache keys are human-readable because they are constructed from
callable's full name and arguments and then sanitized to make
memcached happy.
It can be used with or without group_backend. Without group_backend
bulk invalidation is not supported.
Wrapped callable gets `invalidate` methods. Call `invalidate` with
same arguments as function and the result for these arguments will be
invalidated.
"""
if key:
def test(*args, **kwargs):
args = list(args)
args[0] = key
return sanitize_memcached_key(_cache_key(*args, **kwargs))
_get_key = test
else:
_get_key = lambda *args, **kwargs: sanitize_memcached_key(
_cache_key(*args, **kwargs))
if group:
backend_kwargs = {'group': group}
else:
backend_kwargs = {}
if backend:
cache_backend = caches[backend]
else:
cache_backend = caches['default']
def _cached(func):
func_type = _func_type(func)
@wraps(func)
def wrapper(*args, **kwargs):
full_name(*args)
# try to get the value from cache
key = _get_key(wrapper._full_name, func_type, args, kwargs)
value = cache_backend.get(key, **backend_kwargs)
# in case of cache miss recalculate the value and put it to the cache
if value is None:
logger.debug("Cache MISS: %s" % key)
value = func(*args, **kwargs)
cache_backend.set(key, value, timeout, **backend_kwargs)
logger.debug("Cache SET: %s" % key)
else:
logger.debug("Cache HIT: %s" % key)
return value
def invalidate(*args, **kwargs):
"""
Invalidates cache result for function called with passed arguments
"""
full_name(*args)
if not hasattr(wrapper, '_full_name'):
return
key = _get_key(wrapper._full_name, 'function', args, kwargs)
cache_backend.delete(key, **backend_kwargs)
logger.debug("Cache DELETE: %s" % key)
def force_recalc(*args, **kwargs):
"""
Forces a call to the function & sets the new value in the cache
"""
full_name(*args)
key = _get_key(wrapper._full_name, func_type, args, kwargs)
value = func(*args, **kwargs)
cache_backend.set(key, value, timeout, **backend_kwargs)
return value
def full_name(*args):
# full name is stored as attribute on first call
if not hasattr(wrapper, '_full_name'):
name, _args = _func_info(func, args)
wrapper._full_name = name
def require_cache(*args, **kwargs):
"""
Only pull from cache, do not attempt to calculate
"""
full_name(*args)
key = _get_key(wrapper._full_name, func_type, args, kwargs)
logger.debug("Require cache %s" % key)
value = cache_backend.get(key, **backend_kwargs)
if not value:
logger.info("Could not find required cache %s" % key)
raise NoCachedValueException
return value
def get_cache_key(*args, **kwargs):
""" Returns name of cache key utilized """
full_name(*args)
key = _get_key(wrapper._full_name, 'function', args, kwargs)
return key
wrapper.require_cache = require_cache
wrapper.invalidate = invalidate
wrapper.force_recalc = force_recalc
wrapper.get_cache_key = get_cache_key
return wrapper
return _cached
