Bring database_sync_to_async into repo

Removes the bulk of having Channels installed when no functionality from the app aside from this command is being used.

NOTICE

@@ -0,0 +1 @@
+Some parts of Nautobot-App-Chatops are based upon `channels`, licensed under BSD-3-Clause by Django Software Foundation.

nautobot_chatops/sockets/slack.py

@@ -4,15 +4,14 @@
 import json
 import shlex
 
-from channels.db import database_sync_to_async
 from django.conf import settings
 from slack_sdk.socket_mode.aiohttp import SocketModeClient
 from slack_sdk.socket_mode.request import SocketModeRequest
 from slack_sdk.socket_mode.response import SocketModeResponse
 from slack_sdk.web.async_client import AsyncWebClient
 
 from nautobot_chatops.dispatchers.slack import SlackDispatcher
-from nautobot_chatops.utils import socket_check_and_enqueue_command
+from nautobot_chatops.utils import database_sync_to_async, socket_check_and_enqueue_command
 from nautobot_chatops.workers import commands_help, get_commands_registry, parse_command_string
 
 

nautobot_chatops/utils.py

@@ -4,8 +4,9 @@
 import sys
 from datetime import datetime, timezone
 
-from channels.db import database_sync_to_async
+from asgiref.sync import SyncToAsync
 from django.conf import settings
+from django.db import close_old_connections
 from django.db.models import Q
 from django.http import HttpResponse, JsonResponse
 from nautobot.core.celery import nautobot_task
@@ -18,6 +19,23 @@
 logger = logging.getLogger(__name__)
 
 
+class DatabaseSyncToAsync(SyncToAsync):
+    """
+    SyncToAsync version that cleans up old database connections when it exits.
+    Sourced from Channels, see NOTICE file for license information.
+    """
+
+    def thread_handler(self, loop, *args, **kwargs):
+        close_old_connections()
+        try:
+            return super().thread_handler(loop, *args, **kwargs)
+        finally:
+            close_old_connections()
+
+
+# The class is TitleCased, but we want to encourage use as a callable/decorator
+database_sync_to_async = DatabaseSyncToAsync
+
 def get_app_config_part(prefix: str) -> dict:
     """Get part of the app config.
 

pyproject.toml

@@ -50,7 +50,6 @@ aiodns = "^1.0"
 aiohttp = "^3.7.3"
 asgiref = "^3.4.1"
 certifi = { version = ">=2021.5.30", optional = true }
-channels = "^4.2.0"
 cloudvision = { version = "^1.1", optional = true }
 cvprac = { version = "^1.0.6", optional = true }
 defusedxml = { version = "^0.7.1", optional = true }