life-towers/backend/src/life_towers/db.py
2026-05-28 21:24:47 +01:00

95 lines
2.8 KiB
Python

"""SQLite connection factory, WAL/FK pragmas, and migration runner."""
from __future__ import annotations
import os
import sqlite3
import time
from contextlib import contextmanager
from importlib import resources
from pathlib import Path
from typing import Generator
import structlog
logger = structlog.get_logger(__name__)
_DB_PATH: Path | None = None
def get_db_path() -> Path:
global _DB_PATH
if _DB_PATH is None:
_DB_PATH = Path(os.environ.get("LIFE_TOWERS_DB_PATH", "/data/life-towers.db"))
return _DB_PATH
def _apply_pragmas(conn: sqlite3.Connection) -> None:
conn.execute("PRAGMA journal_mode=WAL")
conn.execute("PRAGMA foreign_keys=ON")
conn.execute("PRAGMA busy_timeout=5000")
def get_connection() -> sqlite3.Connection:
"""Open a new connection with required pragmas applied."""
path = get_db_path()
path.parent.mkdir(parents=True, exist_ok=True)
conn = sqlite3.connect(str(path), check_same_thread=False)
conn.row_factory = sqlite3.Row
_apply_pragmas(conn)
return conn
@contextmanager
def db_connection() -> Generator[sqlite3.Connection, None, None]:
"""Context manager yielding a connection that is closed on exit."""
conn = get_connection()
try:
yield conn
finally:
conn.close()
def _migration_files() -> list[tuple[str, str]]:
"""Return [(filename, sql)] for every migration, in lexical order.
Migrations ship as package data under `life_towers/migrations/`, so they
travel with the wheel and are resolvable regardless of cwd or how the
package is installed (editable, wheel, or PYTHONPATH).
"""
pkg_files = resources.files("life_towers").joinpath("migrations")
out: list[tuple[str, str]] = []
for entry in sorted(pkg_files.iterdir(), key=lambda p: p.name):
if entry.name.endswith(".sql"):
out.append((entry.name, entry.read_text()))
return out
def run_migrations(conn: sqlite3.Connection) -> None:
"""Apply pending SQL migrations in lexical order."""
conn.execute(
"""
CREATE TABLE IF NOT EXISTS schema_migrations (
filename TEXT PRIMARY KEY,
applied_at INTEGER NOT NULL
)
"""
)
conn.commit()
for filename, sql in _migration_files():
row = conn.execute(
"SELECT filename FROM schema_migrations WHERE filename = ?",
(filename,),
).fetchone()
if row is not None:
continue
logger.info("applying_migration", filename=filename)
conn.executescript(sql)
conn.execute(
"INSERT INTO schema_migrations (filename, applied_at) VALUES (?, ?)",
(filename, int(time.time())),
)
conn.commit()
logger.info("migration_applied", filename=filename)