fix: replace deprecated datetime.utcnow() with datetime.now(tz=timezone.utc)

[themavik]

Summary

datetime.utcnow() has been deprecated since Python 3.12 because it returns a naive datetime object that carries no timezone information, making it error-prone when mixed with timezone-aware datetimes. The recommended replacement is datetime.now(tz=timezone.utc) which returns a proper timezone-aware UTC datetime.

Changes

Replaced all 8 occurrences of datetime.utcnow() across 7 files:

Source files (5)

• elementary/utils/time.py — get_now_utc_str()
• elementary/monitor/fetchers/alerts/schema/pending_alerts.py — alert timestamp defaults
• elementary/monitor/data_monitoring/alerts/data_monitoring_alerts.py — suppression interval comparison
• elementary/messages/messaging_integrations/teams_webhook.py — message send timestamp
• elementary/messages/messaging_integrations/slack_webhook.py — message send timestamp
• elementary/messages/messaging_integrations/file_system.py — filename generation and send timestamp

Test files (2)

• tests/unit/monitor/fetchers/alerts/schemas/test_alert_data_schema.py
• tests/mocks/fetchers/alerts_fetcher_mock.py

Behavior

The returned datetime values are identical in absolute terms (both represent "now in UTC"), but datetime.now(tz=timezone.utc) is timezone-aware and won't produce deprecation warnings in Python 3.12+.

Assisted by Claude Opus 4.6 max thinking

Made with Cursor

Summary by CodeRabbit

Release Notes

• Bug Fixes
  • Improved timezone handling throughout the application to ensure consistent and accurate UTC timestamp representation across all time-sensitive features.

[github-actions]

👋 @themavik
Thank you for raising your pull request.
Please make sure to add tests and document all user-facing changes.
You can do this by editing the docs files in this pull request.

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR systematically replaces naive UTC timestamps with timezone-aware UTC timestamps across 8 files by importing timezone and substituting datetime.utcnow() calls with datetime.now(tz=timezone.utc).

Changes

Cohort / File(s)	Summary
Messaging Integrations elementary/messages/messaging_integrations/file_system.py, slack_webhook.py, teams_webhook.py	Added timezone import and replaced datetime.utcnow() with datetime.now(tz=timezone.utc) for timezone-aware UTC timestamp generation in filename formatting and message timestamps.
Monitoring & Alerts elementary/monitor/data_monitoring_alerts.py, elementary/monitor/fetchers/alerts/schema/pending_alerts.py	Imported timezone and changed UTC time retrieval from datetime.utcnow() to datetime.now(tz=timezone.utc) for suppression logic and alert schema timestamp defaults.
Utilities elementary/utils/time.py	Updated get_now_utc_str() to use datetime.now(timezone.utc) instead of datetime.utcnow() for timezone-aware UTC datetime string generation.
Test Utilities tests/mocks/fetchers/alerts_fetcher_mock.py, tests/unit/monitor/fetchers/alerts/schemas/test_alert_data_schema.py	Added timezone import and replaced datetime.utcnow() with datetime.now(tz=timezone.utc) for timezone-aware test fixture timestamps.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Poem

🐰 Hops with glee through timezones aware,
No more naive UTC floating bare!
With timezone-aware stamps so bright,
The datetime dance is now just right! ✨

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: replacing deprecated datetime.utcnow() with timezone-aware datetime.now(tz=timezone.utc) across multiple files.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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No actionable comments were generated in the recent review. 🎉

🧹 Recent nitpick comments

elementary/monitor/data_monitoring/alerts/data_monitoring_alerts.py (1)

204-204: convert_time_to_timezone is now redundant for an already timezone-aware UTC datetime.

datetime.now(tz=timezone.utc) already returns a timezone-aware UTC datetime. Wrapping it in convert_time_to_timezone (with no target timezone) just performs a no-op UTC→UTC conversion. You could simplify to:

-        current_time_utc = convert_time_to_timezone(datetime.now(tz=timezone.utc))
+        current_time_utc = datetime.now(tz=timezone.utc)

This works because last_sent_time on line 214 is still converted independently via convert_time_to_timezone(last_sent_time), and both sides will be UTC-aware for the subtraction.

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