dify/api/extensions/ext_database.py

import logging

import gevent
from sqlalchemy import event
from sqlalchemy.pool import Pool

from dify_app import DifyApp
from models import db

logger = logging.getLogger(__name__)

# Global flag to avoid duplicate registration of event listener
_GEVENT_COMPATIBILITY_SETUP: bool = False


def _safe_rollback(connection) -> None:
    """Safely rollback database connection.

    Args:
        connection: Database connection object
    """
    try:
        connection.rollback()
    except Exception:  # pylint: disable=broad-exception-caught
        logger.exception("Failed to rollback connection")


def _setup_gevent_compatibility() -> None:
    global _GEVENT_COMPATIBILITY_SETUP  # pylint: disable=global-statement

    # Avoid duplicate registration
    if _GEVENT_COMPATIBILITY_SETUP:
        return

    @event.listens_for(Pool, "reset")
    def _safe_reset(dbapi_connection, connection_record, reset_state) -> None:  # pylint: disable=unused-argument
        if reset_state.terminate_only:
            return

        # Safe rollback for connection
        try:
            hub = gevent.get_hub()
            if hasattr(hub, "loop") and getattr(hub.loop, "in_callback", False):
                gevent.spawn_later(0, lambda: _safe_rollback(dbapi_connection))
            else:
                _safe_rollback(dbapi_connection)
        except (AttributeError, ImportError):
            _safe_rollback(dbapi_connection)

    _GEVENT_COMPATIBILITY_SETUP = True


def init_app(app: DifyApp):
    db.init_app(app)
    _setup_gevent_compatibility()