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fix(database): use naive datetime to match DB column type - #4
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Changed datetime.now(timezone.utc) to datetime.now() in models and CRUD to resolve asyncpg error: can't subtract offset-naive and offset-aware datetimes The DB columns are TIMESTAMP WITHOUT TIME ZONE, so the app must use naive datetimes to be compatible.
📝 WalkthroughWalkthroughThe changes switch from UTC-aware datetimes ( Changes
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Actionable comments posted: 2
🤖 Prompt for all review comments with AI agents
Verify each finding against the current code and only fix it if needed.
Inline comments:
In `@app/database/crud.py`:
- Line 84: Add a new helper function utc_now_naive() in app/database/models.py
that returns datetime.now(timezone.utc).replace(tzinfo=None), export it, then
update the created_at and updated_at Column defaults in models.py to use
utc_now_naive; next, import utc_now_naive into app/database/crud.py and replace
all usages of datetime.now() (specifically the assignments to device.updated_at
and the five other assignments referenced) with utc_now_naive() so both model
defaults and the six CRUD updates consistently use UTC-naive timestamps.
In `@app/database/models.py`:
- Around line 84-85: The created_at and updated_at Field default_factories use
datetime.now() which yields local-naive timestamps; replace them to use a
UTC-naive helper (e.g., utc_now()) that returns
datetime.now(timezone.utc).replace(tzinfo=None) and update the Field defaults
for created_at and updated_at to call that helper; also replace the six similar
occurrences in app/database/crud.py to use the same utc_now() helper so all
stored datetimes are UTC-naive and consistent across deployments.
🪄 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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📒 Files selected for processing (2)
app/database/crud.pyapp/database/models.py
| setattr(device, key, value) | ||
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| device.updated_at = datetime.now(timezone.utc) | ||
| device.updated_at = datetime.now() |
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The suggested helper function utc_now_naive() does not exist in the codebase and must be created first.
The concern about datetime.now() using server-local time is valid and needs fixing. However, the suggested fix is incomplete—it references a helper that hasn't been defined yet and doesn't address the same issue in app/database/models.py where created_at and updated_at defaults also use datetime.now().
To fix this properly:
- Add a
utc_now_naive()helper toapp/database/models.pythat returnsdatetime.now(timezone.utc).replace(tzinfo=None)(or equivalent) - Update both models.py defaults and all six crud.py assignments (lines 84, 114, 142, 254, 284, 312) to use this helper
- Ensure the helper is exported and imported consistently
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@app/database/crud.py` at line 84, Add a new helper function utc_now_naive()
in app/database/models.py that returns
datetime.now(timezone.utc).replace(tzinfo=None), export it, then update the
created_at and updated_at Column defaults in models.py to use utc_now_naive;
next, import utc_now_naive into app/database/crud.py and replace all usages of
datetime.now() (specifically the assignments to device.updated_at and the five
other assignments referenced) with utc_now_naive() so both model defaults and
the six CRUD updates consistently use UTC-naive timestamps.
| created_at: datetime = Field(default_factory=lambda: datetime.now()) | ||
| updated_at: datetime = Field(default_factory=lambda: datetime.now()) |
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Use UTC-naive timestamps, not local-naive, to preserve correct timestamp semantics.
datetime.now() creates local-wall-clock naive datetimes, which means on a non-UTC deployment (e.g., Asia/Bangkok +07:00), created_at and updated_at will be stored as local time instead of UTC—changing what the values semantically represent. The DB requires naive datetimes, but that doesn't mean you should use local time. Extract a UTC helper that returns datetime.now(timezone.utc).replace(tzinfo=None) so stored timestamps remain consistent across deployments and DST changes.
Suggested fix
from datetime import datetime, timezone
from typing import Optional, Tuple
VALID_FRAMERS: Tuple[str, ...] = ("RTU", "SOCKET", "ASCII")
VALID_REGISTER_TYPES: Tuple[str, ...] = ("holding", "input", "coil", "discrete")
+
+
+def utc_now_naive() -> datetime:
+ """Return the current UTC time without timezone info for TIMESTAMP WITHOUT TIME ZONE columns."""
+ return datetime.now(timezone.utc).replace(tzinfo=None)
class ModbusDevice(SQLModel, table=True):
...
- created_at: datetime = Field(default_factory=lambda: datetime.now())
- updated_at: datetime = Field(default_factory=lambda: datetime.now())
+ created_at: datetime = Field(default_factory=utc_now_naive)
+ updated_at: datetime = Field(default_factory=utc_now_naive)
class PollingTarget(SQLModel, table=True):
...
- created_at: datetime = Field(default_factory=lambda: datetime.now())
- updated_at: datetime = Field(default_factory=lambda: datetime.now())
+ created_at: datetime = Field(default_factory=utc_now_naive)
+ updated_at: datetime = Field(default_factory=utc_now_naive)Also update app/database/crud.py (6 occurrences):
-device.updated_at = datetime.now()
+device.updated_at = utc_now_naive()📝 Committable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.
| created_at: datetime = Field(default_factory=lambda: datetime.now()) | |
| updated_at: datetime = Field(default_factory=lambda: datetime.now()) | |
| created_at: datetime = Field(default_factory=utc_now_naive) | |
| updated_at: datetime = Field(default_factory=utc_now_naive) |
🤖 Prompt for AI Agents
Verify each finding against the current code and only fix it if needed.
In `@app/database/models.py` around lines 84 - 85, The created_at and updated_at
Field default_factories use datetime.now() which yields local-naive timestamps;
replace them to use a UTC-naive helper (e.g., utc_now()) that returns
datetime.now(timezone.utc).replace(tzinfo=None) and update the Field defaults
for created_at and updated_at to call that helper; also replace the six similar
occurrences in app/database/crud.py to use the same utc_now() helper so all
stored datetimes are UTC-naive and consistent across deployments.
Related issue
Summary
datetime.now(timezone.utc)todatetime.now()in database models and CRUD operationsRoot Cause
TIMESTAMP WITHOUT TIME ZONE(naive)datetime.now(timezone.utc))Scope
app/database/models.py,app/database/crud.pymetrics.py,modbus_client.py, newdocs/docker-compose.ymlTesting
create_polling_target(session, target)with UTC-aware datetimecreate_polling_target(session, target)with naive datetimecreated_at=2026-04-16 08:11:11.544190, tzinfo=NoneReviewer Focus
app/database/crud.py,app/database/models.pyNotes
Summary by CodeRabbit