Mockredis is not Python 3-compatible when using Lua

[beamerblvd]

Mockredis claims to be Python 3-compatible on the README, and perhaps it is for many uses cases, but it depends on a very old python-lunatic-bugfix library that has not be updated in years and is not Python 3 compatible, so there's no way to use Mockredis with Lua and Python 3. Including mockredispy[lua]~=2.9 in my setup.py results in this error:

Collecting lunatic-python-bugfix==1.1.1 (from mockredispy[lua]~=2.9->pysoa==0.18.1)
  Using cached lunatic-python-bugfix-1.1.1.tar.gz
    Complete output from command python setup.py egg_info:
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/private/var/folders/kf/1sq3029d6v3bvtg6066zxwyh0000gp/T/pip-build-nx1ghdoa/lunatic-python-bugfix/setup.py", line 5, in <module>
        import commands
    ModuleNotFoundError: No module named 'commands'
    
    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /private/var/folders/kf/1sq3029d6v3bvtg6066zxwyh0000gp/T/pip-build-nx1ghdoa/lunatic-python-bugfix/

Need an update to a Python 3-compatible library. This author has forked the Lunatic project and kept it up-to-date, but doesn't seem interested in publishing to PyPi. He has opened a solicitation for transfer of ownership, and perhaps you would be willing to take ownership and publish it?

In the meantime, I am looking at forking it for the purposes of publishing once to PyPi, but I can't commit the time necessary to take ownership.

[beamerblvd]

Another issue I encountered that makes it further not-Python-3-compatible:

    def _python_to_lua(oval):
        ...
        elif isinstance(pval, str):
            # Python string --> Lua userdata
            return pval
        elif isinstance(pval, bool):
            # Python bool--> Lua boolean
            return lua.eval(str(pval).lower())
        elif isinstance(pval, (int, long, float)):

Does not account for unicode strings, blindly uses long, which doesn't exist in Python 3.

[beamerblvd]

Hopefully this will help: In order to get this to work, I had to install that other Lunatic dependency, and make the following changes to mockredis.script.Script:

def _execute_lua(self, keys, args, client):
    """
    Patch MockRedis+Lua for error_reply
    """
    lua, lua_globals = Script._import_lua(self.load_dependencies)
    lua_globals.KEYS = self._python_to_lua(keys)
    lua_globals.ARGV = self._python_to_lua(args)

    def _call(*call_args):
        # redis-py and native redis commands are mostly compatible argument
        # wise, but some exceptions need to be handled here:
        if str(call_args[0]).lower() == 'lrem':
            response = client.call(
                call_args[0], call_args[1],
                call_args[3],  # "count", default is 0
                call_args[2])
        else:
            response = client.call(*call_args)
        return self._python_to_lua(response)

    def _error_reply(err):
        return self._python_to_lua({'err': err})

    lua_globals.redis = {'call': _call, 'error_reply': _error_reply}
    return self._lua_to_python(lua.execute(self.script), return_status=True)


# noinspection PyDecorator
@staticmethod
def _lua_to_python(lval, return_status=False):
    """
    Patch MockRedis+Lua for Python 3 compatibility
    """
    # noinspection PyUnresolvedReferences
    import lua
    lua_globals = lua.globals()
    if lval is None:
        # Lua None --> Python None
        return None
    if lua_globals.type(lval) == "table":
        # Lua table --> Python list
        pval = []
        for i in lval:
            if return_status:
                if i == 'ok':
                    return lval[i]
                if i == 'err':
                    raise ResponseError(lval[i])
                if lval[i] == 'err':
                    raise ResponseError(lval[i + 1])
            pval.append(Script._lua_to_python(lval[i]))
        return pval
    elif isinstance(lval, six.integer_types):
        # Lua number --> Python long
        return six.integer_types[-1](lval)
    elif isinstance(lval, float):
        # Lua number --> Python float
        return float(lval)
    elif lua_globals.type(lval) == "userdata":
        # Lua userdata --> Python string
        return str(lval)
    elif lua_globals.type(lval) == "string":
        # Lua string --> Python string
        return lval
    elif lua_globals.type(lval) == "boolean":
        # Lua boolean --> Python bool
        return bool(lval)
    raise RuntimeError("Invalid Lua type: " + str(lua_globals.type(lval)))


# noinspection PyDecorator
@staticmethod
def _python_to_lua(pval):
    """
    Patch MockRedis+Lua for Python 3 compatibility
    """
    # noinspection PyUnresolvedReferences
    import lua
    if pval is None:
        # Python None --> Lua None
        return lua.eval("")
    if isinstance(pval, (list, tuple, set)):
        # Python list --> Lua table
        # e.g.: in lrange
        #     in Python returns: [v1, v2, v3]
        #     in Lua returns: {v1, v2, v3}
        lua_list = lua.eval("{}")
        lua_table = lua.eval("table")
        for item in pval:
            lua_table.insert(lua_list, Script._python_to_lua(item))
        return lua_list
    elif isinstance(pval, dict):
        # Python dict --> Lua dict
        # e.g.: in hgetall
        #     in Python returns: {k1:v1, k2:v2, k3:v3}
        #     in Lua returns: {k1, v1, k2, v2, k3, v3}
        lua_dict = lua.eval("{}")
        lua_table = lua.eval("table")
        for k, v in six.iteritems(pval):
            lua_table.insert(lua_dict, Script._python_to_lua(k))
            lua_table.insert(lua_dict, Script._python_to_lua(v))
        return lua_dict
    elif isinstance(pval, tuple(set(six.string_types + (six.binary_type, )))):
        # Python string --> Lua userdata
        return pval
    elif isinstance(pval, bool):
        # Python bool--> Lua boolean
        return lua.eval(str(pval).lower())
    elif isinstance(pval, six.integer_types + (float, )):
        # Python int --> Lua number
        lua_globals = lua.globals()
        return lua_globals.tonumber(str(pval))

    raise RuntimeError("Invalid Python type: " + str(type(pval)))

I will try to post a pull request tonight.

[beamerblvd]

Submitted pull request #133.

[advance512]

For people having issue with this..

We just moved to fakeredis. Pretty simple, and a drop in replacement.

Just do:
pip install fakeredis[lua]==0.16.0

and then:

`from fakeredis import FakeStrictRedis`

@mock.patch('redis.Redis', FakeStrictRedis)
def .......etcetc

Simple. I hope Location Labs wake up at some point..