feature request: extend redis backend

[cabrinha]

Let's extend the redis backend to support more actions like:

• https://redis.io/commands/scan
• https://redis.io/commands/hkeys
• https://redis.io/commands/keys

This would be in order to scan or get all keys for a given plugin and iterate over them.

I'm trying to create a "Karma" plugin and I'd like to show the top Karma scores:

from machine.plugins.base import MachineBasePlugin
from machine.plugins.decorators import listen_to, respond_to
import re


class Karma(MachineBasePlugin):
    @respond_to(r'(?P<user>.*) \+\+')
    def up(self, msg, user):
        if self.storage.has(user):
            karma = self.storage.get(user)
            karma += 1
            self.storage.set(user, karma)
            msg.say('{}\'s karma is now: {}'.format(user, karma))
        else:
            self.storage.set(user, 1)
            msg.say('No karma found for: {}, setting to 1'.format(user))

    @respond_to(r'(?P<user>.*) \-\-')
    def down(self, msg, user):
        if self.storage.has(user):
            karma = self.storage.get(user)
            karma -= 1
            self.storage.set(user, karma)
            msg.say('{}\'s karma is now: {}'.format(user, karma))
        else:
            self.storage.set(user, -1)
            msg.say('No karma found for: {}, setting to -1'.format(user))

    @respond_to(r'.*(top karma).*')
    def top(self, msg):
        for i in self.storage.keys(pattern='*'):
            print(i)

in machine/storage/backends/redis.py:

...
    def get(self, key):
        return self._redis.get(self._prefix(key))

    def keys(self, pattern):
        return self._redis.keys(pattern='*')
...

Something like this...

But, I get: AttributeError: 'PluginStorage' object has no attribute 'keys'

[DonDebonair]

Great idea! I'll have to think a bit on it, but I'll get back to you on this!

edit: the implementation you suggest cannot be used as-is, because what SlackMachine does by default, is prefixing keys in Redis with a unique identifier for each plugin. This should be taken into account when scanning. The pattern provided through the keys(...) method could be prefixed with the unique idea for example.

[cabrinha]

That's fine. I assume that you mean something along the lines of this:

    def keys(self, key):
        return self._redis.scan_iter(pattern='{}:*'.format(self._prefix(key)))
...

I'm adding the following right underneath http://slack-machine.readthedocs.io/en/latest/_modules/machine/storage/backends/base.html#MachineBaseStorage.get:

    def keys(self, key, shared=False):
        """Retrieve data by key

        :param key: key for the data to retrieve
        :param shared: ``True/False`` wether to retrieve data from the shared (global) namespace.
        :return: the data, or ``None`` if the key cannot be found/has expired
        """
        namespaced_key = self._namespace_key(key, shared)
        # value = Storage.get_instance().get(namespaced_key)
        value = Storage.get_instance().keys(namespaced_key)
        if value:
            return dill.loads(value)
        else:
            return None

But, I'm still getting the error:

AttributeError: 'PluginStorage' object has no attribute 'keys'

Is there something else I'm missing? It's fine if this method could be renamed to "get_all_keys", or something of the sort. I'd like to extend the functionality of the storage backend to support more (or all) redis-py functions, if possible.

After modifying these files, do I just run python3 setup.py install again?