chore: update datetime usage to use datetime.now(UTC) for consistency across the application

Author: gainsborouo

backend/app/api/services/ai_exam.py

@@ -108,7 +108,7 @@ async def _get_job_result():
                         return res
                     else:
                         raise TypeError("Task result must be a dict")
-                except Exception as e:
+                except Exception as e:  # noqa: BLE001 - ARQ result failures are retried
                     last_err = e
                 await asyncio.sleep(0.05)
             if last_err:
@@ -118,7 +118,7 @@ async def _get_job_result():
         if job_status == "complete":
             response.result = await _get_job_result()
             response.completed_at = (
-                metadata.get("completed_at") or datetime.utcnow().isoformat()
+                metadata.get("completed_at") or datetime.now(UTC).isoformat()
             )
             await websocket.send_json(response.dict())
             await websocket.close(code=1000)
@@ -153,15 +153,15 @@ async def _get_job_result():
                         if status_enum is None
                         else _STATUS_MAP.get(status_enum, "unknown")
                     )
-                except Exception:
+                except Exception:  # noqa: BLE001 - status polling is best-effort
                     current_status = last_sent_status
 
                 if current_status and current_status != last_sent_status:
                     last_sent_status = current_status
 
                     if current_status == "complete":
                         result = await _get_job_result()
-                        completed_at = datetime.utcnow().isoformat()
+                        completed_at = datetime.now(UTC).isoformat()
                         metadata["completed_at"] = completed_at
                         metadata["status"] = "complete"
                         await redis.set(
@@ -228,7 +228,7 @@ async def _get_job_result():
 
                     result = await _get_job_result()
 
-                    completed_at = datetime.utcnow().isoformat()
+                    completed_at = datetime.now(UTC).isoformat()
                     metadata["completed_at"] = completed_at
                     metadata["status"] = "complete"
                     await redis.set(
@@ -248,7 +248,7 @@ async def _get_job_result():
                     )
                     await websocket.close(code=1000)
                     return
-    except Exception:
+    except Exception:  # noqa: BLE001 - close the WebSocket on an unexpected failure
         await websocket.close(code=1011)
         return
 
@@ -311,7 +311,7 @@ async def submit_generate_task(
         metadata = {
             "user_id": current_user.user_id,
             "archive_ids": request.archive_ids,
-            "created_at": datetime.utcnow().isoformat(),
+            "created_at": datetime.now(UTC).isoformat(),
             "status": "pending",
         }
         await redis.set(
@@ -328,7 +328,7 @@ async def submit_generate_task(
 
     except HTTPException:
         raise
-    except Exception as e:
+    except Exception as e:  # noqa: BLE001 - translate unexpected backend failures
         raise HTTPException(
             status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
             detail=f"Failed to submit task: {e!s}",
@@ -369,7 +369,7 @@ async def delete_task(
 
     except HTTPException:
         raise
-    except Exception as e:
+    except Exception as e:  # noqa: BLE001 - translate unexpected backend failures
         raise HTTPException(
             status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
             detail=f"Failed to delete task: {e!s}",
@@ -405,7 +405,7 @@ async def get_api_key_status(
         return ApiKeyResponse(has_api_key=has_api_key, api_key_masked=api_key_masked)
     except HTTPException:
         raise
-    except Exception as e:
+    except Exception as e:  # noqa: BLE001 - translate unexpected database failures
         raise HTTPException(
             status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
             detail=f"Failed to get API key status: {e!s}",
@@ -452,7 +452,7 @@ async def update_api_key(
         return ApiKeyResponse(has_api_key=has_api_key, api_key_masked=api_key_masked)
     except HTTPException:
         raise
-    except Exception as e:
+    except Exception as e:  # noqa: BLE001 - translate validation and database failures
         # Check if it's an API key validation error
         if "API key" in str(e) or "authentication" in str(e).lower():
             raise HTTPException(

backend/app/api/services/archives.py

@@ -116,7 +116,7 @@ async def upload_archive(
 
     except HTTPException:
         raise
-    except Exception as e:
+    except Exception as e:  # noqa: BLE001 - translate storage and database failures
         raise HTTPException(
             status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
             detail=f"Failed to upload file: {e!s}",

backend/app/api/services/courses.py

@@ -188,7 +188,7 @@ async def _broadcast_discussion(archive_id: int, payload: dict):
     for ws in list(sockets):
         try:
             await ws.send_json(payload)
-        except Exception:
+        except Exception:  # noqa: BLE001 - a disconnected socket is removed
             dead.append(ws)
 
     if dead:
@@ -314,7 +314,7 @@ async def archive_discussion_ws(
                 return
             try:
                 data = json.loads(raw)
-            except Exception:
+            except json.JSONDecodeError:
                 continue
 
             if not isinstance(data, dict):

backend/app/db/init_db.py

@@ -1,3 +1,4 @@
+import asyncio
 import os
 import subprocess
 import unicodedata
@@ -25,11 +26,13 @@ async def init_db():
     # Run Alembic migrations instead of create_all
     try:
         # Run alembic upgrade head to apply all migrations
-        result = subprocess.run(
+        result = await asyncio.to_thread(
+            subprocess.run,
             ["uv", "run", "alembic", "upgrade", "head"],
             cwd=os.path.dirname(os.path.dirname(os.path.dirname(__file__))),
             capture_output=True,
             text=True,
+            check=False,
         )
         if result.returncode != 0:
             print(f"Alembic migration failed: {result.stderr}")
@@ -39,7 +42,7 @@ async def init_db():
                 await conn.commit()
         else:
             print("Database migrations applied successfully")
-    except Exception as e:
+    except Exception as e:  # noqa: BLE001 - migration failure falls back to create_all
         print(f"Error running migrations: {e}")
         # Fallback to create_all
         async with engine.begin() as conn:

backend/app/services/auth.py

@@ -6,7 +6,9 @@
 from app.core.config import settings
 
 
-async def oauth_callback(code: str, state: str = None, stored_state: str = None):
+async def oauth_callback(
+    code: str, state: str | None = None, stored_state: str | None = None
+):
     """
     Verify CSRF token and handle OAuth callback for NYCU OAuth
     """

backend/app/worker.py

@@ -1,8 +1,9 @@
 import io
 import logging
-from datetime import datetime
+from datetime import UTC, datetime
 from functools import lru_cache
 from pathlib import Path
+from typing import ClassVar
 
 from arq import create_pool
 from arq.connections import RedisSettings
@@ -220,7 +221,7 @@ async def publish_event(status: str, *, error: str | None = None):
         if not redis or not task_id:
             return
         try:
-            fields = {"status": status, "ts": datetime.utcnow().isoformat()}
+            fields = {"status": status, "ts": datetime.now(UTC).isoformat()}
             if error:
                 fields["error"] = error
             stream_key = f"ai_exam:task_events:{task_id}"
@@ -253,7 +254,7 @@ class WorkerSettings:
     """ARQ worker settings"""
 
     redis_settings = RedisSettings.from_dsn(settings.REDIS_URL)
-    functions = [generate_ai_exam_task]
+    functions: ClassVar[list] = [generate_ai_exam_task]
 
     max_jobs = 5  # Max concurrent jobs
     job_timeout = 600  # Job timeout in seconds

backend/pyproject.toml

@@ -34,3 +34,6 @@ dev = [
     "pytest-cov>=7.0.0",
     "ruff>=0.16.1",
 ]
+
+[tool.ruff.lint.flake8-bugbear]
+extend-immutable-calls = ["fastapi.Depends", "fastapi.Form"]