Fixes for datetime UTC warnings in Python

I was getting the following warning for one of my Python test suites:

DeprecationWarning: datetime.datetime.utcnow() is deprecated and scheduled for removal in a future version. Use timezone-aware objects to represent datetimes in UTC: datetime.datetime.now(datetime.UTC).

I also saw a deprecation warning elsewhere for my usage of datetime.datetime.utcfromtimestamp(iso_timestamp_string).

I tried switching to datetime.UTC for the first warning, but that caused my tests to fail on versions of Python prior to 3.11. I support all versions of Python that have not yet hit EOL for support, which is currently Python 3.9 and higher.

According to the documentation datetime.UTC was added in Python 3.11 as an alias for datetime.timezone.utc - so I switched my usage of datetime.utcnow() to the following instead:

import datetime

utcnow = datetime.datetime.now(datetime.timezone.utc)

These tests now passed for Python 3.9+.

I found another hint in the docs for replacing the now deprecated datetime.datetime.utcfromtimestamp:

Warning: Because naive datetime objects are treated by many datetime methods as local times, it is preferred to use aware datetimes to represent times in UTC. As such, the recommended way to create an object representing a specific timestamp in UTC is by calling datetime.fromtimestamp(timestamp, tz=timezone.utc).

Again, timezone.utc was the right fix here to keep things working in pre-3.11 versions:

import datetime

utc_datetime = datetime.datetime.fromtimestamp(created_string, datetime.timezone.utc)

Here's the commit where I fixed both of these warnings for my LLM project.

Created 2024-12-12T14:58:13-08:00, updated 2024-12-13T19:34:32-08:00 · History · Edit