env.py

#  Copyright (c) University College London Hospitals NHS Foundation Trust
#
#  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.
"""Alembic configuration"""

from logging.config import fileConfig

from decouple import Config, RepositoryEnv
from sqlalchemy import URL, create_engine

from alembic import context

env_config = Config(RepositoryEnv("migrations.env"))

# 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 core.db import models

target_metadata = models.Base.metadata


# 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 include_name(name: str, type_: str, parent_names: str) -> bool:  # noqa: ARG001
    """Filtering of allowed table names"""
    if type_ == "schema":
        return name in [target_metadata.schema]
    return True


def get_pixl_db_url() -> URL:
    """Create PIXL database URL for connection."""
    return URL.create(
        drivername="postgresql+psycopg2",
        host=env_config("PIXL_DB_HOST"),
        port=env_config("PIXL_DB_PORT", int),
        username=env_config("PIXL_DB_USER"),
        password=env_config("PIXL_DB_PASSWORD"),
        database=env_config("PIXL_DB_NAME"),
    )


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 = get_pixl_db_url()
    context.configure(
        url=url,
        target_metadata=target_metadata,
        literal_binds=True,
        dialect_opts={"paramstyle": "named"},
        include_schemas=True,
        include_name=include_name,
        version_table_schema=target_metadata.schema,
    )

    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.

    """
    url = get_pixl_db_url()
    connectable = create_engine(url)

    with connectable.connect() as connection:
        context.configure(
            connection=connection,
            target_metadata=target_metadata,
            include_schemas=True,
            include_name=include_name,
            version_table_schema=target_metadata.schema,
        )

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


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