refactor: Centralize database session management in a shared dependency module

README.md

@@ -29,7 +29,7 @@ The architecture is documented in [docs/architecture.md](docs/architecture.md).
 The project is organized into several key directories:
 
 - `models/`: Contains SQLAlchemy models representing database tables.
-- `routes/`: Defines FastAPI routes for API endpoints.
+- `routes/`: Defines FastAPI routes for API endpoints; shared dependencies like `get_db` live in `routes/dependencies.py`.
 - `services/`: Business logic and service layer.
 - `components/`: Frontend components (to be defined).
 - `config/`: Configuration files and settings.

docs/architecture.md

@@ -10,7 +10,7 @@ The backend leverages SQLAlchemy for ORM mapping to a PostgreSQL database.
 
 ## System Components
 
-- **FastAPI backend** (`main.py`, `routes/`): hosts REST endpoints for scenarios, parameters, costs, consumption, production, equipment, maintenance, simulations, and reporting. Each router encapsulates request/response schemas and DB access patterns.
+- **FastAPI backend** (`main.py`, `routes/`): hosts REST endpoints for scenarios, parameters, costs, consumption, production, equipment, maintenance, simulations, and reporting. Each router encapsulates request/response schemas and DB access patterns, leveraging a shared dependency module (`routes/dependencies.get_db`) for SQLAlchemy session management.
 - **Service layer** (`services/`): houses business logic. `services/reporting.py` produces statistical summaries, while `services/simulation.py` provides the Monte Carlo integration point.
 - **Persistence** (`models/`, `config/database.py`): SQLAlchemy models map to PostgreSQL tables in schema `bricsium_platform`. Relationships connect scenarios to derived domain entities.
 - **Presentation** (`templates/`, `components/`): server-rendered views support data entry (scenario and parameter forms) and the dashboard visualization powered by Chart.js.

docs/implementation_plan.md

@@ -151,3 +151,11 @@ Next actionable items:
 4. Scaffold Monte Carlo Simulation endpoints (`services/simulation.py`, `routes/simulations.py`, tests).
 5. Scaffold Reporting endpoints (`services/reporting.py`, `routes/reporting.py`, front-end Dashboard, tests).
 6. Add CI job for tests and coverage.
+
+## UI Template Audit (2025-10-20)
+
+- Existing HTML templates: `ScenarioForm.html`, `ParameterInput.html`, and `Dashboard.html` (reporting summary view).
+- Coverage gaps remain for costs, consumption, production, equipment, maintenance, and simulation workflows—no dedicated templates yet.
+- Shared layout primitives (navigation/header/footer) are absent; current pages duplicate boilerplate markup.
+- Dashboard currently covers reporting metrics but should be wired to a central `/` route once the shared layout lands.
+- Next steps align with the updated TODO checklist: introduce a `base.html`, refactor existing templates to extend it, and scaffold placeholder pages for the remaining features.

routes/consumption.py

@@ -4,21 +4,11 @@ from fastapi import APIRouter, Depends, status
 from pydantic import BaseModel, ConfigDict, PositiveFloat
 from sqlalchemy.orm import Session
 
-from config.database import SessionLocal
 from models.consumption import Consumption
+from routes.dependencies import get_db
 
 
 router = APIRouter(prefix="/api/consumption", tags=["Consumption"])
-
-
-def get_db():
-    db = SessionLocal()
-    try:
-        yield db
-    finally:
-        db.close()
-
-
 class ConsumptionBase(BaseModel):
     scenario_id: int
     amount: PositiveFloat

routes/costs.py

@@ -1,23 +1,17 @@
-from fastapi import APIRouter, Depends
-from sqlalchemy.orm import Session
 from typing import List, Optional
+
+from fastapi import APIRouter, Depends
 from pydantic import BaseModel, ConfigDict
-from config.database import SessionLocal
+from sqlalchemy.orm import Session
+
 from models.capex import Capex
 from models.opex import Opex
+from routes.dependencies import get_db
 
 router = APIRouter(prefix="/api/costs", tags=["Costs"])
-
-
-def get_db():
-    db = SessionLocal()
-    try:
-        yield db
-    finally:
-        db.close()
-
-
 # Pydantic schemas for Capex
+
+
 class CapexCreate(BaseModel):
     scenario_id: int
     amount: float

routes/dependencies.py

@@ -0,0 +1,13 @@
+from collections.abc import Generator
+
+from sqlalchemy.orm import Session
+
+from config.database import SessionLocal
+
+
+def get_db() -> Generator[Session, None, None]:
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()

routes/distributions.py

@@ -1,25 +1,19 @@
+from typing import Dict, List
+
 from fastapi import APIRouter, Depends
-from sqlalchemy.orm import Session
-from typing import List
 from pydantic import BaseModel, ConfigDict
-from config.database import SessionLocal
+from sqlalchemy.orm import Session
+
 from models.distribution import Distribution
+from routes.dependencies import get_db
 
 router = APIRouter(prefix="/api/distributions", tags=["Distributions"])
 
 
-def get_db():
-    db = SessionLocal()
-    try:
-        yield db
-    finally:
-        db.close()
-
-
 class DistributionCreate(BaseModel):
     name: str
     distribution_type: str
-    parameters: dict
+    parameters: Dict[str, float | int]
 
 
 class DistributionRead(DistributionCreate):

routes/equipment.py

@@ -1,22 +1,16 @@
-from fastapi import APIRouter, Depends
-from sqlalchemy.orm import Session
 from typing import List, Optional
+
+from fastapi import APIRouter, Depends
 from pydantic import BaseModel, ConfigDict
-from config.database import SessionLocal
+from sqlalchemy.orm import Session
+
 from models.equipment import Equipment
+from routes.dependencies import get_db
 
 router = APIRouter(prefix="/api/equipment", tags=["Equipment"])
-
-
-def get_db():
-    db = SessionLocal()
-    try:
-        yield db
-    finally:
-        db.close()
-
-
 # Pydantic schemas
+
+
 class EquipmentCreate(BaseModel):
     scenario_id: int
     name: str

routes/maintenance.py

@@ -5,21 +5,13 @@ from fastapi import APIRouter, Depends, HTTPException, status
 from pydantic import BaseModel, ConfigDict, PositiveFloat
 from sqlalchemy.orm import Session
 
-from config.database import SessionLocal
 from models.maintenance import Maintenance
+from routes.dependencies import get_db
 
 
 router = APIRouter(prefix="/api/maintenance", tags=["Maintenance"])
 
 
-def get_db():
-    db = SessionLocal()
-    try:
-        yield db
-    finally:
-        db.close()
-
-
 class MaintenanceBase(BaseModel):
     equipment_id: int
     scenario_id: int

routes/parameters.py

@@ -4,10 +4,10 @@ from fastapi import APIRouter, Depends, HTTPException
 from pydantic import BaseModel, ConfigDict, field_validator
 from sqlalchemy.orm import Session
 
-from config.database import SessionLocal
 from models.distribution import Distribution
 from models.parameters import Parameter
 from models.scenario import Scenario
+from routes.dependencies import get_db
 
 router = APIRouter(prefix="/api/parameters", tags=["parameters"])
 
@@ -45,17 +45,6 @@ class ParameterRead(ParameterCreate):
     id: int
     model_config = ConfigDict(from_attributes=True)
 
-# Dependency
-
-
-def get_db():
-    db = SessionLocal()
-    try:
-        yield db
-    finally:
-        db.close()
-
-
 @router.post("/", response_model=ParameterRead)
 def create_parameter(param: ParameterCreate, db: Session = Depends(get_db)):
     scen = db.query(Scenario).filter(Scenario.id == param.scenario_id).first()

routes/production.py

@@ -4,21 +4,11 @@ from fastapi import APIRouter, Depends, status
 from pydantic import BaseModel, ConfigDict, PositiveFloat
 from sqlalchemy.orm import Session
 
-from config.database import SessionLocal
 from models.production_output import ProductionOutput
+from routes.dependencies import get_db
 
 
 router = APIRouter(prefix="/api/production", tags=["Production"])
-
-
-def get_db():
-    db = SessionLocal()
-    try:
-        yield db
-    finally:
-        db.close()
-
-
 class ProductionOutputBase(BaseModel):
     scenario_id: int
     amount: PositiveFloat

routes/reporting.py

@@ -3,21 +3,12 @@ from typing import Any, Dict, List, cast
 from fastapi import APIRouter, HTTPException, Request, status
 from pydantic import BaseModel
 
-from config.database import SessionLocal
 from services.reporting import generate_report
 
 
 router = APIRouter(prefix="/api/reporting", tags=["Reporting"])
 
 
-def get_db():
-    db = SessionLocal()
-    try:
-        yield db
-    finally:
-        db.close()
-
-
 def _validate_payload(payload: Any) -> List[Dict[str, float]]:
     if not isinstance(payload, list):
         raise HTTPException(

routes/scenarios.py

@@ -1,10 +1,12 @@
-from fastapi import APIRouter, Depends, HTTPException
-from sqlalchemy.orm import Session
-from config.database import SessionLocal
-from models.scenario import Scenario
-from pydantic import BaseModel, ConfigDict
-from typing import Optional
 from datetime import datetime
+from typing import Optional
+
+from fastapi import APIRouter, Depends, HTTPException
+from pydantic import BaseModel, ConfigDict
+from sqlalchemy.orm import Session
+
+from models.scenario import Scenario
+from routes.dependencies import get_db
 
 router = APIRouter(prefix="/api/scenarios", tags=["scenarios"])
 
@@ -22,29 +24,15 @@ class ScenarioRead(ScenarioCreate):
     updated_at: Optional[datetime] = None
     model_config = ConfigDict(from_attributes=True)
 
-# Dependency
-
-
-def get_db():
-    db = SessionLocal()
-    try:
-        yield db
-    finally:
-        db.close()
-
-
 @router.post("/", response_model=ScenarioRead)
 def create_scenario(scenario: ScenarioCreate, db: Session = Depends(get_db)):
-    print(f"Creating scenario with name: {scenario.name}")
     db_s = db.query(Scenario).filter(Scenario.name == scenario.name).first()
     if db_s:
-        print(f"Scenario with name {scenario.name} already exists.")
         raise HTTPException(status_code=400, detail="Scenario already exists")
     new_s = Scenario(name=scenario.name, description=scenario.description)
     db.add(new_s)
     db.commit()
     db.refresh(new_s)
-    print(f"Scenario with name {scenario.name} created successfully.")
     return new_s
 
 

routes/simulations.py

@@ -1,27 +1,19 @@
-from typing import List, Optional, cast
+from typing import Dict, List, Optional
 
 from fastapi import APIRouter, Depends, HTTPException, status
 from pydantic import BaseModel, PositiveInt
 from sqlalchemy.orm import Session
 
-from config.database import SessionLocal
 from models.parameters import Parameter
 from models.scenario import Scenario
 from models.simulation_result import SimulationResult
+from routes.dependencies import get_db
 from services.reporting import generate_report
 from services.simulation import run_simulation
 
 router = APIRouter(prefix="/api/simulations", tags=["Simulations"])
 
 
-def get_db():
-    db = SessionLocal()
-    try:
-        yield db
-    finally:
-        db.close()
-
-
 class SimulationParameterInput(BaseModel):
     name: str
     value: float
@@ -48,7 +40,7 @@ class SimulationRunResponse(BaseModel):
     scenario_id: int
     iterations: int
     results: List[SimulationResultItem]
-    summary: dict
+    summary: Dict[str, float | int]
 
 
 def _load_parameters(db: Session, scenario_id: int) -> List[SimulationParameterInput]:

tests/unit/conftest.py

@@ -57,38 +57,11 @@ def api_client(db_session: Session) -> Generator[TestClient, None, None]:
         finally:
             pass
 
-    # override all routers that use get_db
+    from routes import dependencies as route_dependencies
-    from routes import (
-        consumption,
-        costs,
-        distributions,
-        equipment,
-        maintenance,
-        parameters,
-        production,
-        reporting,
-        scenarios,
-        simulations,
-    )
 
-    overrides = {
+    app.dependency_overrides[route_dependencies.get_db] = override_get_db
-        consumption.get_db: override_get_db,
-        costs.get_db: override_get_db,
-        distributions.get_db: override_get_db,
-        equipment.get_db: override_get_db,
-        maintenance.get_db: override_get_db,
-        parameters.get_db: override_get_db,
-        production.get_db: override_get_db,
-        reporting.get_db: override_get_db,
-        scenarios.get_db: override_get_db,
-        simulations.get_db: override_get_db,
-    }
-
-    for dependency, override in overrides.items():
-        app.dependency_overrides[dependency] = override
 
     with TestClient(app) as client:
         yield client
 
-    for dependency in overrides:
+    app.dependency_overrides.pop(route_dependencies.get_db, None)
-        app.dependency_overrides.pop(dependency, None)