🐛 A proper cross-version solution for the utcnow() issue.

No need to maintain two different pieces of logic - a `utcnow()` for
Python < 3.11 and `now(datetime.UTC)` for Python >= 3.11.

`datetime.timezone.utc` existed long before datetime.UTC and that's what
the `utcnow` facade should use.

This means that all the `utcnow()` will always have `tzinfo=UTC`
regardless of the Python version.

There's still a problem with the `utcnow()`-generated timestamps that
have been generated by previous versions of Python and stored on the db.

Therefore, when the code performs comparisons with timestamps fetched
from the db, it should always explicitly do a `.replace(tzinfo=utc)` to
ensure that we always compare offset-aware datetime representations.

See blog post for technical details:
https://manganiello.blog/wheres-my-time-again

platypush/entities/__init__.py

@@ -1,10 +1,8 @@
-from datetime import timedelta
 import logging
 from threading import Event
+from time import time
 from typing import Collection, Optional
 
-from platypush.utils import utcnow
-
 from ._base import (
     Entity,
     EntityKey,
@@ -47,8 +45,8 @@ def get_entities_engine(timeout: Optional[float] = None) -> EntitiesEngine:
 
     :param timeout: Timeout in seconds (default: None).
     """
-    time_start = utcnow()
-    while not timeout or (utcnow() - time_start < timedelta(seconds=timeout)):
+    time_start = time()
+    while not timeout or (time() - time_start < timeout):
         if _engine:
             break
 

platypush/plugins/bluetooth/_ble/_event_handler.py

@@ -1,4 +1,4 @@
-from datetime import timedelta
+from datetime import timedelta, timezone
 from logging import getLogger
 from queue import Queue
 from typing import Callable, Collection, Dict, Final, List, Optional, Type
@@ -99,7 +99,8 @@ event_matchers: Dict[
         )
         and (
             not (old and old.updated_at)
-            or utcnow() - old.updated_at >= timedelta(seconds=_rssi_update_interval)
+            or utcnow() - old.updated_at.replace(tzinfo=timezone.utc)
+            >= timedelta(seconds=_rssi_update_interval)
         )
     ),
 }

platypush/plugins/calendar/ical/__init__.py

@@ -97,8 +97,7 @@ class CalendarIcalPlugin(Plugin, CalendarInterface):
             if (
                 event['status'] != 'cancelled'
                 and event['end'].get('dateTime')
-                and event['end']['dateTime']
-                >= utcnow().replace(tzinfo=datetime.timezone.utc).isoformat()
+                and event['end']['dateTime'] >= utcnow().isoformat()
                 and (
                     (
                         only_participating

platypush/plugins/google/calendar/__init__.py

@@ -71,7 +71,7 @@ class GoogleCalendarPlugin(GooglePlugin, CalendarInterface):
         :meth:`platypush.plugins.calendar.CalendarPlugin.get_upcoming_events`.
         """
 
-        now = utcnow().isoformat() + 'Z'
+        now = utcnow().replace(tzinfo=None).isoformat() + 'Z'
         service = self.get_service('calendar', 'v3')
         result = (
             service.events()

platypush/plugins/sun/__init__.py

@@ -68,7 +68,7 @@ class SunPlugin(RunnablePlugin):
         dt = datetime.datetime.strptime(
             f'{now.year}-{now.month:02d}-{now.day:02d} {t}',
             '%Y-%m-%d %I:%M:%S %p',
-        ).replace(tzinfo=datetime.UTC)
+        ).replace(tzinfo=datetime.timezone.utc)
 
         if dt < now:
             dt += datetime.timedelta(days=1)

platypush/user/__init__.py

@@ -115,9 +115,13 @@ class UserManager:
                 .first()
             )
 
-            if not user_session or (
-                user_session.expires_at and user_session.expires_at < utcnow()
-            ):
+            expires_at = (
+                user_session.expires_at.replace(tzinfo=datetime.timezone.utc)
+                if user_session and user_session.expires_at
+                else None
+            )
+
+            if not user_session or (expires_at and expires_at < utcnow()):
                 return None, None
 
             user = session.query(User).filter_by(user_id=user_session.user_id).first()

platypush/utils/__init__.py

@@ -816,14 +816,10 @@ def wait_for_either(*events, timeout: Optional[float] = None, cls: Type = Event)
 
 def utcnow():
     """
-    A workaround util to maintain compatibility both with Python >= 3.12 (which
-    deprecated datetime.utcnow) and Python < 3.12 (which doesn't have
-    datetime.UTC).
+    utcnow() without tears. It always returns a datetime object in UTC
+    timezone.
     """
-    if hasattr(datetime, 'UTC'):
-        return datetime.datetime.now(datetime.UTC)
-
-    return datetime.datetime.utcnow()
+    return datetime.datetime.now(datetime.timezone.utc)
 
 
 # vim:sw=4:ts=4:et: