Custom connection class overriden by redis uri

[m-novikov]

It not possible to pass custom connection class via kwargs if redis uri starts with rediss:// (secure connection) or unix://

Version: 3.5.3
Platform: pyton3.9, fedora

Description:

Here are tests to reproduce. Discussion in aio-libs-abandoned/aioredis-py#1209 implies that it's intentional, but I am not sure if this is expected behavior.

import pytest
from redis import connection, from_url


@pytest.mark.parametrize("proto,ConnBase", [
    ("rediss", connection.SSLConnection), 
    ("unix", connection.UnixDomainSocketConnection),
])
def test_custom_connection_class_connection_pool(proto, ConnBase):
    class MyConn(ConnBase):
        pass

    pool = connection.ConnectionPool.from_url(
        url=f"{proto}:///tmp/redis.sock", connection_class=MyConn,
    )
    conn = pool.make_connection()
    assert isinstance(conn, MyConn)


@pytest.mark.parametrize("proto,ConnBase", [
    ("rediss", connection.SSLConnection), 
    ("unix", connection.UnixDomainSocketConnection),
])
def test_from_url_custom_connection_class(proto, ConnBase):
    class MyConn(ConnBase):
        pass

    redis = from_url(
        url=f"{proto}://127.0.0.1", connection_class=MyConn,
    )
    conn = redis.connection_pool.make_connection()
    assert isinstance(conn, MyConn)

Related issue in aioredis-py aio-libs-abandoned/aioredis-py#1209

[adiberk]

Second this. This is a huge issue. If I would like to use SSL connection, the from_url method will essentially prevent this!
Eventually ConnectionPool.from_url calls the following
def __init__(self, connection_class=Connection, max_connections=None, **connection_kwargs):
I believe this is where it causing the issue?

[chayim]

Given what we currently have for connections - I think this makes sense.
Note, I generally think we probably should do a bit of a rethink on connections and add environments to support multiple test scenarios, but we're not there yet.

I'm going to merge this into 4.1.0rc2 - and I back-issued a tracker for environments.