examples/alembic/migrations/env.py - main - githubmirror/ydb-sqlalchemy

examples/alembic/migrations/env.py
95 строк2 KB
Oleg Ovcharuk
Alembic usage example guide
10 дек 2024, 15:36
10 дек 2024, 15:368236de4
from logging.config import fileConfig

import sqlalchemy as sa
from sqlalchemy import engine_from_config
from sqlalchemy import pool

from alembic import context
from alembic.ddl.impl import DefaultImpl


# 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 myapp import mymodel
# target_metadata = mymodel.Base.metadata

from models import *
target_metadata = 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.


class YDBImpl(DefaultImpl):
    __dialect__ = "yql"


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"},
    )

    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
        )

        ctx = context.get_context()
        ctx._version = sa.Table(  # noqa: SLF001
            ctx.version_table,
            sa.MetaData(),
            sa.Column("version_num", sa.String(32), nullable=False),
            sa.Column("id", sa.Integer(), nullable=True, primary_key=True),
        )

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


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