namespaced keys

On the Danga website, they are describing a way to group keys under the same namespace, with a way to invalidate all those key on a single operation by defining a unique value like time() for the namespace.

>>> cache.set('the_namespace', time.time())
>>> key = cache.get('the_namespace') + ':key1'
>>> cache.set(key1, 'value1')
>>> key2 = cache.get('the_namespace') + ':key2'
>>> cache.set(key2, 'value1')

To invalidate all keys, we just have to increment the namespace key:

>>> cache,incr('the_namespace')

The keys will automatically change when they are calculated, thus invalidating all existing values (which can naturally expire then.)

It could be interesting to add that feature in python-memcached for people that need to group cached values.