From 9ab05cbe3f23d442b5bc73311e0c3e8b075e396e Mon Sep 17 00:00:00 2001 From: kwzrd Date: Tue, 13 Apr 2021 19:05:45 +0200 Subject: Branding: use tz-aware datetime representation Using `datetime.utcnow` produces a tz-naive object. When converting the object into a POSIX timestamp (L212), the library then converts the naive object into UTC, which will offset it unless the local timezone is UTC. We prevent this behaviour by using an Arrow repr instead, which is by default tz-aware. Since the object already knows it is in UTC, it does not shift when converting to a timestamp. Because L233 used `fromtimestamp` rather than `utcfromtimestamp`, the timestamp then got converted back into local time, canceling the previous error. Therefore, the bug wasn't observable from logs, as the times looked correct, but were being stored incorrectly. By using `Arrow.utcfromtimestamp`, the created object will be aware of being UTC again, which is more safe. --- bot/exts/backend/branding/_cog.py | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/bot/exts/backend/branding/_cog.py b/bot/exts/backend/branding/_cog.py index 0a4ddcc88..fdc4a4167 100644 --- a/bot/exts/backend/branding/_cog.py +++ b/bot/exts/backend/branding/_cog.py @@ -3,12 +3,13 @@ import contextlib import logging import random import typing as t -from datetime import datetime, time, timedelta +from datetime import timedelta from enum import Enum from operator import attrgetter import async_timeout import discord +from arrow import Arrow from async_rediscache import RedisCache from discord.ext import commands, tasks @@ -208,7 +209,7 @@ class Branding(commands.Cog): if success: await self.cache_icons.increment(next_icon) # Push the icon into the next iteration. - timestamp = datetime.utcnow().timestamp() + timestamp = Arrow.utcnow().timestamp() await self.cache_information.set("last_rotation_timestamp", timestamp) return success @@ -229,8 +230,8 @@ class Branding(commands.Cog): await self.rotate_icons() return - last_rotation = datetime.fromtimestamp(last_rotation_timestamp) - difference = (datetime.utcnow() - last_rotation) + timedelta(minutes=5) + last_rotation = Arrow.utcfromtimestamp(last_rotation_timestamp) + difference = (Arrow.utcnow() - last_rotation) + timedelta(minutes=5) log.trace(f"Icons last rotated at {last_rotation} (difference: {difference}).") @@ -485,11 +486,11 @@ class Branding(commands.Cog): await self.daemon_loop() log.trace("Daemon before: calculating time to sleep before loop begins.") - now = datetime.utcnow() + now = Arrow.utcnow() # The actual midnight moment is offset into the future to prevent issues with imprecise sleep. - tomorrow = now + timedelta(days=1) - midnight = datetime.combine(tomorrow, time(minute=1)) + tomorrow = now.shift(days=1) + midnight = tomorrow.replace(hour=0, minute=1, second=0, microsecond=0) sleep_secs = (midnight - now).total_seconds() log.trace(f"Daemon before: sleeping {sleep_secs} seconds before next-up midnight: {midnight}.") -- cgit v1.2.3