Parth
e7d75c3b05
* Rewrite comments in Google developer documentation style Rewrite the comments and docstrings across the backend core modules so they read plainly. The previous prose was accurate but dense and figurative, which made it slow to skim. Applies the Google developer documentation style guide: short sentences, active voice, present tense, American spelling, and no metaphors, idioms, or rhetorical asides. Replaces em-dash chains with separate sentences.
75 lines
2.4 KiB
Python
75 lines
2.4 KiB
Python
import os
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from pathlib import Path
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from sqlalchemy import create_engine, event
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from sqlalchemy.orm import DeclarativeBase, sessionmaker
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# AIDND_DB_PATH lets deployments (Docker volume, hosted disk) relocate the
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# SQLite database; default stays backend/data.db for local runs. The parent
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# directory also hosts the auto-generated secret.key (see security.py), so
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# DB_PATH stays defined even when Postgres is in use.
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_env_db_path = os.environ.get("AIDND_DB_PATH")
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DB_PATH = (
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Path(_env_db_path).resolve()
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if _env_db_path
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else Path(__file__).resolve().parent.parent / "data.db"
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)
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# `AIDND_DATABASE_URL`, or the conventional `DATABASE_URL`, switches the app to
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# a server database. Any SQLAlchemy URL works, and hosted deploys use Postgres,
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# which Phase 9 settled on Neon for. If neither variable is set, the app uses
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# SQLite.
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DATABASE_URL = (
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os.environ.get("AIDND_DATABASE_URL", "").strip()
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or os.environ.get("DATABASE_URL", "").strip()
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)
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def _normalize_url(url: str) -> str:
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"""Map the postgres:// / postgresql:// schemes hosts hand out to the
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psycopg3 driver installed in requirements.txt."""
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for prefix in ("postgres://", "postgresql://"):
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if url.startswith(prefix):
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return "postgresql+psycopg://" + url[len(prefix):]
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return url
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if DATABASE_URL:
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engine = create_engine(
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_normalize_url(DATABASE_URL),
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# Serverless Postgres (Neon) suspends idle databases; pre-ping
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# replaces silently-dead pooled connections instead of erroring.
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pool_pre_ping=True,
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# Store/read naive UTC like SQLite does, regardless of server default.
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connect_args={"options": "-c timezone=UTC"},
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)
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else:
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DB_PATH.parent.mkdir(parents=True, exist_ok=True)
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engine = create_engine(
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f"sqlite:///{DB_PATH}",
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connect_args={"check_same_thread": False},
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)
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@event.listens_for(engine, "connect")
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def _enable_sqlite_foreign_keys(dbapi_connection, _record):
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# SQLite ships with foreign keys OFF per connection; without this every
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# ondelete=CASCADE/SET NULL in models.py is silently ignored.
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cursor = dbapi_connection.cursor()
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cursor.execute("PRAGMA foreign_keys=ON")
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cursor.close()
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SessionLocal = sessionmaker(bind=engine, autoflush=False, expire_on_commit=False)
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class Base(DeclarativeBase):
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pass
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def get_db():
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db = SessionLocal()
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try:
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yield db
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finally:
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db.close()
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