fix: replace deprecated datetime.utcnow() with timezone-aware alternative

[nightcityblade]

Description

Replace remaining datetime.utcnow() calls with datetime.now(timezone.utc) across 4 files. datetime.utcnow() is deprecated since Python 3.12 and returns naive datetimes that can cause subtle timezone bugs.

Files changed:

• cognee/get_token.py — JWT expiry timestamp
• cognee/eval_framework/modal_run_eval.py — eval timestamp
• cognee/infrastructure/databases/cache/redis/RedisAdapter.py — cache entry timestamp
• cognee/infrastructure/databases/cache/fscache/FsCacheAdapter.py — cache entry timestamp

Acceptance Criteria

• No remaining utcnow() calls in the codebase
• All timestamps are now timezone-aware (UTC)

Type of Change

• Bug fix (non-breaking change that fixes an issue)

Pre-submission Checklist

• I have tested my changes thoroughly before submitting this PR
• This PR contains minimal changes necessary to address the issue/feature
• My code follows the project's coding standards and style guidelines
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if applicable)
• All new and existing tests pass
• I have searched existing PRs to ensure this change hasn't been submitted already
• I have linked any relevant issues in the description
• My commits have clear and descriptive messages

DCO Affirmation

I affirm that all code in every commit of this pull request conforms to the terms of the Topoteretes Developer Certificate of Origin.

Summary by CodeRabbit

• Chores
  • Standardized timestamp handling to use timezone-aware UTC datetimes across the app, affecting filename generation, token expiry timestamps, and cache/redis records.
  • Timestamps now consistently include explicit UTC information while preserving existing timestamp formats and public behaviors. No public interfaces were changed.

[pull-checklist]

Please make sure all the checkboxes are checked:

• I have tested these changes locally.
• I have reviewed the code changes.
• I have added end-to-end and unit tests (if applicable).
• I have updated the documentation and README.md file (if necessary).
• I have removed unnecessary code and debug statements.
• PR title is clear and follows the convention.
• I have tagged reviewers or team members for feedback.

[github-actions]

Hello @nightcityblade, thank you for submitting a PR! We will respond as soon as possible.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: db02fc29-bbaa-49cd-ae26-03eb1e647bfe

📥 Commits

Reviewing files that changed from the base of the PR and between fa37428 and a72a7ef.

📒 Files selected for processing (1)

• cognee/get_token.py

🚧 Files skipped from review as they are similar to previous changes (1)

• cognee/get_token.py

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Walkthrough

Replaced timezone-naive datetime.utcnow() calls with timezone-aware datetime.now(datetime.timezone.utc) across four files, adjusting imports where needed. Output formats and filename/timestamp string formats were preserved.

Changes

Cohort / File(s)	Summary
Timezone-aware UTC timestamp updates cognee/eval_framework/modal_run_eval.py, cognee/get_token.py, cognee/infrastructure/databases/cache/fscache/FsCacheAdapter.py, cognee/infrastructure/databases/cache/redis/RedisAdapter.py	Replaced timezone-naive datetime.utcnow() with timezone-aware datetime.now(datetime.timezone.utc) for timestamp generation (filenames, JWT exp claim, cache QA entry timestamps). Updated imports to include timezone where required; no other logic or public APIs changed.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Possibly related PRs

• fix: use timezone-aware UTC datetime in temporal awareness #2432 — Makes the same replacement of naive datetime.utcnow() with datetime.now(timezone.utc) across codebase.

Suggested labels

core-team

Suggested reviewers

• Vasilije1990

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 50.00% 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
Title check	✅ Passed	The title clearly and specifically describes the main change: replacing deprecated datetime.utcnow() calls with timezone-aware alternatives.
Description check	✅ Passed	The description covers all required template sections including clear description, acceptance criteria, type of change, and pre-submission checklist items.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@cognee/get_token.py`:
- Line 13: The file fails ruff formatting; run the formatter and commit the
result: execute `ruff format cognee/get_token.py` (and optionally `ruff check
cognee/get_token.py --line-length 100`) to fix formatting and import/style
issues in the token creation code (the dict containing the "exp" datetime), then
add and commit the reformatted file so the CI passes.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro

Run ID: 0828fab1-797a-4910-9a2a-493dd7f1395a

📥 Commits

Reviewing files that changed from the base of the PR and between 863ed64 and fa37428.

📒 Files selected for processing (4)

• cognee/eval_framework/modal_run_eval.py
• cognee/get_token.py
• cognee/infrastructure/databases/cache/fscache/FsCacheAdapter.py
• cognee/infrastructure/databases/cache/redis/RedisAdapter.py