Channel layer object empty

[igmt]

Hi, really like your project.
I'm trying to get this working on my dev environment but I keep getting an empty Channel layer object.

I added the needed config, see below and ran migrations (which worked), but below code will return None.

from channels.layers import get_channel_layer
c = get_channel_layer()
print(c) #prints None

Below part of my config:

DATABASES = {
    "default": {
        "ENGINE": "django.db.backends.postgresql",
        "NAME": "postgres",
        "USER": "postgres",
        "PASSWORD": "postgres",
        "HOST": "postgres",
    },
    "channels_postgres": {
        "ENGINE": "django.db.backends.postgresql",
        "NAME": "postgres",
        "USER": "postgres",
        "PASSWORD": "postgres",
        "HOST": "postgres",
        "PORT": "5432",
    }
}

CHANNEL_LAYERS = {
    "default": {
        "BACKEND": "channels_postgres.core.PostgresChannelLayer",
        "CONFIG": {
            "ENGINE": "django.db.backends.postgresql",
            "NAME": "postgres",
            "USER": "postgres",
            "PASSWORD": "postgres",
            "HOST": "postgres",
            "PORT": "5432",
        }
    }
}

Part of requirements.txt

channels==4.2.2
channels-redis==4.2.0
channels-postgres==1.1.2

Guess it is something stupid I'm missing :)

[jgentil]

Getting the same error.

[jgentil]

It looks like it might be a bug in Django that gets weirdly exposed here. Django needs a setting in the database settings dict called TIME_ZONE if settings.USE_TZ = True is set. There's supposed to be a default, but the code doesn't create a default. Weird. This code also only runs when psycopg3 is used, which was a recent patch I see.

It's weird because when Django does the initialization it runs fine, but when Channels does it, it fails.

I added "TIME_ZONE": "UTC" to your CHANNEL_LAYERS setting and it started working.

Unfortunately all of the unit tests test only with USE_TZ = False.

[jgentil]

Django sets TIME_ZONE by default to None (which is valid) in ConnectionHandler.configure_settings but channels-postgres does not use ConnectionHandler and goes straight to instantiating a backend. This is problematic, because it tries to get the connection parameters from the DatabaseWrapper but that does not fully initialize the parameters.

If channels-postgres used ConnectionHandler from Django, which is a singleton instance on django.db.connections, we could actually find the connection we define in DATABASES called channels_postgres and re-use those parameters instead of needing to pass in the config to CHANNEL_LAYERS.

[danidee10]

The DatabaseWrapper code was a leftover from the time when the library used aiopg. You're right that with psycopg3 I should be able to get the connection parameters from the connection object that django creates.

Although, I wonder if the connection/psycopg3 connection object that django creates exposes the connection parameters in a portable way.

In the future, if django's db layer becomes async safe: we could get a new connection by calling get_connection instead of using psycopg3 directly to create a new connection.

I'll see what I can knock out this weekend.