Files
DocsGPT/application/storage/db/engine.py
2026-04-12 12:24:58 +01:00

74 lines
2.3 KiB
Python

"""SQLAlchemy Core engine factory for the user-data Postgres database.
The engine is lazily constructed on first use and cached as a module-level
singleton. Repositories and the Alembic env module both obtain connections
through this factory, so pool tuning lives in one place.
``POSTGRES_URI`` can be written in any of the common Postgres URI forms::
postgres://user:pass@host:5432/docsgpt
postgresql://user:pass@host:5432/docsgpt
Both are accepted and normalized internally to the psycopg3 dialect
(``postgresql+psycopg://``) by ``application.core.settings``. Operators
don't need to know about SQLAlchemy dialect prefixes.
"""
from typing import Optional
from sqlalchemy import Engine, create_engine
from application.core.settings import settings
_engine: Optional[Engine] = None
def _resolve_uri() -> str:
"""Return the Postgres URI for user-data tables.
Raises:
RuntimeError: If ``settings.POSTGRES_URI`` is unset. Callers that
reach this path without a configured URI have a setup bug — the
error message points them at the right setting.
"""
if not settings.POSTGRES_URI:
raise RuntimeError(
"POSTGRES_URI is not configured. Set it in your .env to a "
"psycopg3 URI such as "
"'postgresql+psycopg://user:pass@host:5432/docsgpt'."
)
return settings.POSTGRES_URI
def get_engine() -> Engine:
"""Return the process-wide SQLAlchemy Engine, creating it if needed.
Returns:
A SQLAlchemy ``Engine`` configured with a pooled connection to
Postgres via psycopg3.
"""
global _engine
if _engine is None:
_engine = create_engine(
_resolve_uri(),
pool_size=10,
max_overflow=20,
pool_pre_ping=True, # survive PgBouncer / idle-disconnect recycles
pool_recycle=1800,
future=True,
)
return _engine
def dispose_engine() -> None:
"""Dispose the pooled connections and reset the singleton.
Called from the Celery ``worker_process_init`` signal so each forked
worker gets a fresh pool instead of sharing file descriptors with the
parent process (which corrupts the pool on fork).
"""
global _engine
if _engine is not None:
_engine.dispose()
_engine = None