env.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.

from logging.config import fileConfig

from alembic import context
from sqlalchemy import engine_from_config
from sqlalchemy import pool

# this is the Alembic Config object, which provides
# access to the values within the .ini file in use.
config = context.config

# Interpret the config file for Python logging.
# This line sets up loggers basically.
if config.config_file_name is not None:
  fileConfig(config.config_file_name)

# add your model's MetaData object here
# for 'autogenerate' support
from google.adk.sessions.database_session_service import Base

# Only operate on tables defined in these metadata objects.
TARGET_METADATAS = (Base.metadata,)
target_metadata = TARGET_METADATAS[0]

_ALLOWED_TABLE_NAMES = frozenset(
    table_name
    for metadata in TARGET_METADATAS
    for table_name in metadata.tables
)


def include_object(obj, name, type_, reflected, compare_to):
  """Only include tables (and their indexes) defined in TARGET_METADATAS."""
  if type_ == "table":
    return bool(_ALLOWED_TABLE_NAMES) and name in _ALLOWED_TABLE_NAMES
  if type_ == "index":
    try:
      return obj.table.name in _ALLOWED_TABLE_NAMES
    except AttributeError:
      return False
  return True


# other values from the config, defined by the needs of env.py,
# can be acquired:
# my_important_option = config.get_main_option("my_important_option")
# ... etc.


def run_migrations_offline() -> None:
  """Run migrations in 'offline' mode.

  This configures the context with just a URL
  and not an Engine, though an Engine is acceptable
  here as well.  By skipping the Engine creation
  we don't even need a DBAPI to be available.

  Calls to context.execute() here emit the given string to the
  script output.

  """
  url = config.get_main_option("sqlalchemy.url")
  context.configure(
      url=url,
      target_metadata=target_metadata,
      literal_binds=True,
      dialect_opts={"paramstyle": "named"},
      include_object=include_object,
      version_table="alembic_version_adk",
  )

  with context.begin_transaction():
    context.run_migrations()


def run_migrations_online() -> None:
  """Run migrations in 'online' mode.

  In this scenario we need to create an Engine
  and associate a connection with the context.

  """
  connectable = engine_from_config(
      config.get_section(config.config_ini_section, {}),
      prefix="sqlalchemy.",
      poolclass=pool.NullPool,
  )

  with connectable.connect() as connection:
    context.configure(
        connection=connection,
        target_metadata=target_metadata,
        include_object=include_object,
        version_table="alembic_version_adk",
    )

    with context.begin_transaction():
      context.run_migrations()


if context.is_offline_mode():
  run_migrations_offline()
else:
  run_migrations_online()