class MemcachedAdapter(BaseAdapter):
"""
Exposes a cache store using Memcached.
Exposes `pymemcache`'s exceptions.
"""
def __init__(self, host='localhost', port=11211, **kwargs):
super().__init__()
self.store = Client((host, port), **kwargs)
def set(self, key, value, ttl):
if ttl == -1:
ttl = 0
return self.store.set(key, value, expire=ttl)
def batch_set(self, keys, values, ttls):
# There's two reasons to recode pymemcache.set_multi():
# - It returns a list of keys that failed to be inserted, and the base expects a boolean
# - It only allows a unique ttl for all keys
commands = []
ttls = [0 if ttl == -1 else ttl for ttl in ttls]
for key, value, ttl in zip(keys, values, ttls):
ttl = self.store._check_integer(ttl, 'expire') # pylint: disable=protected-access
key = self.store.check_key(key)
value, flags = self.store.serde.serialize(key, value)
command = b'set ' + key
command += b' ' + str(flags).encode(self.store.encoding)
command += b' ' + ttl
command += b' ' + str(len(value)).encode(
self.store.encoding) + b'\r\n'
command += value.encode(self.store.encoding) + b'\r\n'
commands.append(command)
results = self.store._misc_cmd(commands, 'set', False) # pylint: disable=protected-access
for line in results:
if line == b'NOT_STORED':
return False
return True
def get(self, key):
value = self.store.get(key)
return value
def batch_get(self, keys):
key_to_value = self.store.get_multi(keys)
values = [
key_to_value[key] if key in key_to_value else None for key in keys
]
return values
def delete(self, key):
return self.store.delete(key, noreply=False)
def batch_delete(self, keys):
# Here as well, pymemcache.delete_multi() always returns True
commands = []
for key in keys:
key = self.store.check_key(key)
command = b'delete ' + key + b'\r\n'
commands.append(command)
results = self.store._misc_cmd(commands, 'delete', False) # pylint: disable=protected-access
for line in results:
print(f"\"{line}\"")
if line == b'NOT_FOUND':
return False
return True
def exists(self, key):
# Can't just cast to bool since we can store falsey values
return self.store.get(key) is not None
def flush(self):
return self.store.flush_all(noreply=False)
def ping(self):
return bool(self.store.stats())
@property
def connection_exceptions(self):
return (MemcacheUnexpectedCloseError, MemcacheServerError,
MemcacheUnknownError)
class OCPyMemcacheClient(object):
"""
OCPyMemcacheClient is the instrumented wrapper to provide
traces and metrics to a pymemache.client.base.Client instance.
It takes the exact arguments that a HashClient would take and
underlyingly creates the client which it then wraps.
The same usage pattern for the original client would apply here.
"""
__TRACKING_OPERATION = TrackingOperation()
def __init__(self, server_addr, *args, **kwargs):
self.__pymc = PyMemcacheClient(server_addr, *args, **kwargs)
def add(self, key, value, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.add', self.__pymc.add, key, value,
*args, **kwargs)
def append(self, key, value, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.append', self.__pymc.append, key,
value, *args, **kwargs)
def cas(self, key, value, cas, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.cas', self.__pymc.cas, key, value,
*args, **kwargs)
def check_key(self, key):
# Does not touch the remote end.
return self.__pymc.check_key(key)
def close(self):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.close', self.__pymc.close)
def decr(self, key, value, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.decr', self.__pymc.decr, key, value,
*args, **kwargs)
def delete(self, key, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.delete', self.__pymc.delete, key,
*args, **kwargs)
def delete_many(self, keys, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.delete_many',
self.__pymc.delete_many, keys, *args, **kwargs)
def delete_multi(self, keys, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.delete_multi',
self.__pymc.delete_multi, keys, *args, **kwargs)
def flush_all(self, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.flush_all', self.__pymc.flush_all,
*args, **kwargs)
def get(self, key, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.get', self.__pymc.get, key, *args,
**kwargs)
def get_many(self, keys, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.get_many', self.__pymc.get_many,
key, *args, **kwargs)
def get_multi(self, keys, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.get_multi', self.__pymc.get_multi,
key, *args, **kwargs)
def gets(self, keys, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.gets', self.__pymc.gets, keys,
*args, **kwargs)
def gets_many(self, keys, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.gets_many', self.__pymc.gets_many,
keys, *args, **kwargs)
def incr(self, key, value, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.incr', self.__pymc.incr, key, value,
*args, **kwargs)
def prepend(self, key, value, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.prepend', self.__pymc.prepend, key,
value, *args, **kwargs)
def quit(self, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.quit', self.__pymc.quit, *args,
**kwargs)
def replace(self, key, value, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.replace', self.__pymc.replace, key,
value, *args, **kwargs)
def set(self, key, value, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.set', self.__pymc.set, key, value,
*args, **kwargs)
def set_many(self, values, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.set_many', self.__pymc.set_many,
values, *args, **kwargs)
def set_multi(self, values, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.set_multi', self.__pymc.set_multi,
values, *args, **kwargs)
def stats(self, *args):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.stats', self.__pymc.stats, *args)
def touch(self, key, *args, **kwargs):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.touch', self.__pymc.touch, *args,
**kwargs)
def version(self):
return self.__TRACKING_OPERATION.trace_and_record_stats(
'pymemcache.client.base.Client.version', self.__pymc.version)
