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Merged
Jonathan0823 merged 1 commit into from
Apr 16, 2026
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fix(database): use naive datetime to match DB column type #4

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14 changes: 7 additions & 7 deletions app/database/crud.py
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@

from __future__ import annotations

from datetime import datetime, timezone
from datetime import datetime
from typing import List, Optional

from sqlalchemy.ext.asyncio import AsyncSession
Expand Down Expand Up @@ -81,7 +81,7 @@ async def update_device(
for key, value in update_data.items():
setattr(device, key, value)

device.updated_at = datetime.now(timezone.utc)
device.updated_at = datetime.now()

@coderabbitai coderabbitai Bot Apr 16, 2026

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⚠️ Potential issue | 🟠 Major

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find app -type f -name "*.py" | head -20

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rg -i "def.*now" app/database/ 2>/dev/null || echo "No now functions found"

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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:

  1. Add a utc_now_naive() helper to app/database/models.py that returns datetime.now(timezone.utc).replace(tzinfo=None) (or equivalent)
  2. Update both models.py defaults and all six crud.py assignments (lines 84, 114, 142, 254, 284, 312) to use this helper
  3. 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.

await session.commit()
await session.refresh(device)
logger.info(
Expand Down Expand Up @@ -111,7 +111,7 @@ async def delete_device(session: AsyncSession, device_id: str) -> bool:
return False

device.is_active = False
device.updated_at = datetime.now(timezone.utc)
device.updated_at = datetime.now()
await session.commit()
logger.info(
"device_deleted",
Expand Down Expand Up @@ -139,7 +139,7 @@ async def activate_device(session: AsyncSession, device_id: str) -> bool:
return False

device.is_active = True
device.updated_at = datetime.now(timezone.utc)
device.updated_at = datetime.now()
await session.commit()
logger.info(
"device_activated",
Expand Down Expand Up @@ -251,7 +251,7 @@ async def update_polling_target(
for key, value in update_data.items():
setattr(target, key, value)

target.updated_at = datetime.now(timezone.utc)
target.updated_at = datetime.now()
await session.commit()
await session.refresh(target)
logger.info(
Expand Down Expand Up @@ -281,7 +281,7 @@ async def delete_polling_target(session: AsyncSession, target_id: int) -> bool:
return False

target.is_active = False
target.updated_at = datetime.now(timezone.utc)
target.updated_at = datetime.now()
await session.commit()
logger.info(
"polling_target_deleted",
Expand Down Expand Up @@ -309,7 +309,7 @@ async def activate_polling_target(session: AsyncSession, target_id: int) -> bool
return False

target.is_active = True
target.updated_at = datetime.now(timezone.utc)
target.updated_at = datetime.now()
await session.commit()
logger.info(
"polling_target_activated",
Expand Down
8 changes: 4 additions & 4 deletions app/database/models.py
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Original file line number Diff line number Diff line change
Expand Up @@ -81,8 +81,8 @@ class ModbusDevice(SQLModel, table=True):
max_retries: int = Field(default=5)
retry_delay: float = Field(default=0.1)
is_active: bool = Field(default=True, index=True)
created_at: datetime = Field(default_factory=lambda: datetime.now(timezone.utc))
updated_at: datetime = Field(default_factory=lambda: datetime.now(timezone.utc))
created_at: datetime = Field(default_factory=lambda: datetime.now())
updated_at: datetime = Field(default_factory=lambda: datetime.now())
Comment on lines +84 to +85

@coderabbitai coderabbitai Bot Apr 16, 2026

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⚠️ Potential issue | 🟠 Major

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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.

Suggested change
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.



# Pydantic schemas for API
Expand Down Expand Up @@ -151,8 +151,8 @@ class PollingTarget(SQLModel, table=True):
count: int = Field(default=1, ge=1, le=125)
is_active: bool = Field(default=True, index=True)
description: Optional[str] = Field(default=None, max_length=200)
created_at: datetime = Field(default_factory=lambda: datetime.now(timezone.utc))
updated_at: datetime = Field(default_factory=lambda: datetime.now(timezone.utc))
created_at: datetime = Field(default_factory=lambda: datetime.now())
updated_at: datetime = Field(default_factory=lambda: datetime.now())


# Pydantic schemas for Polling API
Expand Down
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