class Cache:
"""Simple cache backend wrapper using Pinterest's pymemcache;
Attributes:
client (Client): The client object for a single memcached server;
"""
def __init__(self):
self.client = Client((HOST, POST), serde=JsonSerde())
def __repr__(self):
return "<Cache {}>".format(self.client.server)
def get_stats(self, *args):
"""Runs the memcached `stats` command;
Args:
*arg (list): extra string arguments to the “stats” command;
Returns:
A dictionary of the returned stats;
"""
return self.client.stats(args)
def set(self, key, value):
"""Cache setter;
Args:
key (str): unique identifier of pair;
value (str): value for the key;
"""
self.client.set(key, value)
def set_multiple(self, value):
"""A convenience function for setting multiple values;
Args:
key (str): unique identifier of pair;
value (str): value for the key;
"""
self.client.set_multi(value)
def get(self, key):
"""Cache getter;
Args:
key (str): unique identifier of pair;
Returns:
The value for the key if was found;
Raises:
Exception if the key wasn’t found;
"""
return self.client.get(key)
def add(self, key, value):
"""Runs memcached “add” command;
Store data, only if it does not already exist;
Args:
key (str): unique identifier of pair;
value (str): value for the key;
Returns:
return True if value was stored, False if it was not;
"""
return self.client.add(key, value)
def replace(self, key, value):
"""Runs memcached “replace” command;
Store data, but only if the data already exists;
Args:
key (str): unique identifier of pair;
value (str): value for the key;
Returns:
return True if value was stored, False if it was not;
"""
return self.client.replace(key, value)
def append(self, key, value):
"""Runs memcached append command;
Args:
key (str): unique identifier of pair;
value (str): value for the key;
Returns:
return True;
"""
return self.client.append(key, value)
def prepend(self, key, value):
"""Runs memcached “prepend” command;
Same as append, but adding new data before existing data;
Args:
key (str): unique identifier of pair;
value (str): value for the key;
Returns:
return True;
"""
return self.client.prepend(key, value)
def delete(self, key):
"""Runs memcached delete command;"""
return self.client.delete(key)
def delete_many(self, keys):
"""A convenience function to delete multiple keys;"""
return self.client.delete_many(keys)
for i in range(ITERATION_NUM):
key, value = f"some_key-{i}", f"some_value-{i}"
# cmd "set", create/update key:value
assert client.set(key, value)
# cmd "get", get value with key
result = client.get(key).decode("utf-8")
assert result == value
# cmd "delete", delete key
assert client.delete(key)
# cmd "add", create key:value
assert client.set(key, value)
assert client.add(key, value)
# cmd "append", append value
res = client.append(key, "_suffix")
value += "_suffix"
assert client.get(key).decode("utf-8") == value
# cmd "preppend", preppend value
res = client.prepend(key, "prefix_")
value = "prefix_" + value
assert client.get(key).decode("utf-8") == value
# cmd "replace", preppend value
res = client.replace(key, "empty")
assert client.get(key).decode("utf-8") == "empty"
