session.py

# Copyright 2025 Google LLC.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import logging

from sqlalchemy import Engine, create_engine
from sqlalchemy.orm import Session, sessionmaker

from datacommons_db.models.base import Base

logger = logging.getLogger(__name__)




def get_engine(project_id: str, instance_id: str, database_name: str) -> Engine:
    """Create and return a SQLAlchemy engine for Cloud Spanner.

    Args:
      project_id: GCP project ID
      instance_id: Cloud Spanner instance ID
      database_name: Cloud Spanner database name

    Returns:
      SQLAlchemy engine configured for Cloud Spanner
    """
    return create_engine(
        f"spanner+spanner:///projects/{project_id}/instances/{instance_id}/databases/{database_name}",
    )


def get_session(project_id: str, instance_id: str, database_name: str) -> Session:
    """Create and return a SQLAlchemy session for Cloud Spanner.

    Args:
      project_id: GCP project ID
      instance_id: Cloud Spanner instance ID
      database_name: Cloud Spanner database name

    Returns:
      SQLAlchemy session configured for Cloud Spanner
    """
    engine = get_engine(project_id, instance_id, database_name)
    session = sessionmaker(bind=engine)
    return session()