Files
breakpilot-lehrer/timetable-solver-service/app/db.py
T
Benjamin Admin f042f2896b Phase 5: Timefold timetable-solver-service + solution persistence
school-service additions:
  - tt_solution + tt_lesson migration. tt_lesson carries three UNIQUEs
    (solution+class, solution+teacher, solution+room per slot) so the
    DB itself rejects any double-booking the solver might emit by
    mistake.
  - Solution CRUD + GET solutions/:id/lessons endpoint with joined
    class/subject/teacher/room names for display.
  - POST /timetable/solutions creates the row then fires off the
    solver-service via HTTP (5s timeout, mark failed if unreachable).
  - SOLVER_SERVICE_URL config wired through main.go/handlers.

New service timetable-solver-service:
  - Python 3.11 + FastAPI + Timefold Solver 1.21 (Apache-2.0). Dockerfile
    bundles OpenJDK 17 since Timefold for Python is a JPype bridge.
  - app/domain.py — Timefold @planning_entity Lesson with timeslot+room
    as PlanningVariables; @planning_solution Timetable holds problem
    facts (rooms/teachers/etc.) AND rule-fact collections.
  - app/rules.py — frozen dataclasses mirroring 6 of the 15 tt_
    constraint_* tables initially.
  - app/constraints.py — ConstraintProvider with 3 universal hard
    constraints (no double-booking) + 5 DB-driven constraints
    (teacher_unavailable_day/window, teacher_excluded_room,
    room_unavailable, room_requires_type) + 1 quality soft constraint
    (subject_preferred_period). Remaining 9 constraint types ready to
    plug in via the same join pattern.
  - app/repository.py — async loaders for stammdaten + rules; builds
    one Lesson per (curriculum row × weekly_hours), skipping rows
    without a tt_assignment teacher.
  - app/runner.py — runs solver in ThreadPoolExecutor so the FastAPI
    event loop stays responsive. Updates tt_solution status
    pending→running→completed|infeasible|failed.
  - app/main.py — POST /api/v1/solve (202 Accepted, background task),
    GET /api/v1/jobs/{id}, /health. School-service polls tt_solution
    directly instead of GET /jobs for the typical case.
  - docker-compose.yml adds the service on port 8095, depending on
    core-health-check.

Tests:
  - school-service: validator test for CreateTimetableSolutionRequest
    (allows empty name).
  - solver-service: tests/test_domain.py + tests/test_rules.py cover
    construction + hashability of the planning facts. Full solve flow
    deferred to Phase 8 integration with seed data.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-22 00:16:52 +02:00

29 lines
686 B
Python

import asyncpg
from typing import Optional
from .config import settings
_pool: Optional[asyncpg.Pool] = None
async def get_pool() -> asyncpg.Pool:
"""Lazy-init the asyncpg pool. Reused across requests + background jobs."""
global _pool
if _pool is None:
if not settings.database_url:
raise RuntimeError("DATABASE_URL not configured")
_pool = await asyncpg.create_pool(
dsn=settings.database_url,
min_size=2,
max_size=10,
command_timeout=30,
)
return _pool
async def close_pool() -> None:
global _pool
if _pool is not None:
await _pool.close()
_pool = None