From 653953ed924efea363f0d90900d8272ae26b2112 Mon Sep 17 00:00:00 2001 From: Oleg Ovcharuk Date: Tue, 10 Dec 2024 15:08:28 +0300 Subject: [PATCH] Alembic usage example guide --- README.md | 2 + examples/alembic/README.md | 78 ++++++++++++ examples/alembic/__init__.py | 0 examples/alembic/alembic.ini | 117 ++++++++++++++++++ examples/alembic/migrations/README | 1 + examples/alembic/migrations/env.py | 95 ++++++++++++++ examples/alembic/migrations/script.py.mako | 26 ++++ .../820b994ffa7c_create_seasons_table.py | 37 ++++++ .../9085c679f5dc_create_episodes_table.py | 37 ++++++ .../d91d9200b65c_create_series_table.py | 36 ++++++ examples/alembic/models.py | 33 +++++ tox.ini | 2 +- 12 files changed, 463 insertions(+), 1 deletion(-) create mode 100644 examples/alembic/README.md create mode 100644 examples/alembic/__init__.py create mode 100644 examples/alembic/alembic.ini create mode 100644 examples/alembic/migrations/README create mode 100644 examples/alembic/migrations/env.py create mode 100644 examples/alembic/migrations/script.py.mako create mode 100644 examples/alembic/migrations/versions/820b994ffa7c_create_seasons_table.py create mode 100644 examples/alembic/migrations/versions/9085c679f5dc_create_episodes_table.py create mode 100644 examples/alembic/migrations/versions/d91d9200b65c_create_series_table.py create mode 100644 examples/alembic/models.py diff --git a/README.md b/README.md index 26c55c7..c0ec867 100644 --- a/README.md +++ b/README.md @@ -32,6 +32,8 @@ with engine.connect() as conn: ``` +To setup `alembic` to work with `YDB` please check [this example](https://github.com/ydb-platform/ydb-sqlalchemy/tree/main/examples/alembic). + ## Development ### Run Tests: diff --git a/examples/alembic/README.md b/examples/alembic/README.md new file mode 100644 index 0000000..a1b04c3 --- /dev/null +++ b/examples/alembic/README.md @@ -0,0 +1,78 @@ +# Alembic support + +In this example we'll see how to use `alembic` with ydb. + +## Installation + +To make `alembic` work with `YDB` tables please follow these steps: + +* Install `ydb-sqlalchemy` package from PyPi: + +```bash +pip install ydb-sqlalchemy` +``` + +* Install `alembic` package from PyPi: + +```bash +pip install alembic +``` + +## Preparation + +We have to setup `alembic` correctly. +First of all, we should register `YDB` dialect in `env.py`: + +```python3 +from alembic.ddl.impl import DefaultImpl + + +class YDBImpl(DefaultImpl): + __dialect__ = "yql" +``` + +Secondly, since `YDB` do not support updating primary key columns, we have to update alembic table structure. +For this purpose we should update `run_migrations_online` method in `env.py`: + +```python3 +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() +``` + +## Example + +To run this example: +1. Install all dependencies described in `Installation` section. +1. Update `sqlalchemy.url` field in `alembic.ini` config file. +1. Run `alembic upgrade head` to apply all migrations. + +To create new migration just add a few changes in `models.py` and run: +```bash +alembic revision --autogenerate -m "name of your migration" +``` diff --git a/examples/alembic/__init__.py b/examples/alembic/__init__.py new file mode 100644 index 0000000..e69de29 diff --git a/examples/alembic/alembic.ini b/examples/alembic/alembic.ini new file mode 100644 index 0000000..f988bfc --- /dev/null +++ b/examples/alembic/alembic.ini @@ -0,0 +1,117 @@ +# A generic, single database configuration. + +[alembic] +# path to migration scripts +# Use forward slashes (/) also on windows to provide an os agnostic path +script_location = migrations + +# template used to generate migration file names; The default value is %%(rev)s_%%(slug)s +# Uncomment the line below if you want the files to be prepended with date and time +# see https://alembic.sqlalchemy.org/en/latest/tutorial.html#editing-the-ini-file +# for all available tokens +# file_template = %%(year)d_%%(month).2d_%%(day).2d_%%(hour).2d%%(minute).2d-%%(rev)s_%%(slug)s + +# sys.path path, will be prepended to sys.path if present. +# defaults to the current working directory. +prepend_sys_path = . + +# timezone to use when rendering the date within the migration file +# as well as the filename. +# If specified, requires the python>=3.9 or backports.zoneinfo library. +# Any required deps can installed by adding `alembic[tz]` to the pip requirements +# string value is passed to ZoneInfo() +# leave blank for localtime +# timezone = + +# max length of characters to apply to the "slug" field +# truncate_slug_length = 40 + +# set to 'true' to run the environment during +# the 'revision' command, regardless of autogenerate +# revision_environment = false + +# set to 'true' to allow .pyc and .pyo files without +# a source .py file to be detected as revisions in the +# versions/ directory +# sourceless = false + +# version location specification; This defaults +# to ./versions. When using multiple version +# directories, initial revisions must be specified with --version-path. +# The path separator used here should be the separator specified by "version_path_separator" below. +# version_locations = %(here)s/bar:%(here)s/bat:./versions + +# version path separator; As mentioned above, this is the character used to split +# version_locations. The default within new alembic.ini files is "os", which uses os.pathsep. +# If this key is omitted entirely, it falls back to the legacy behavior of splitting on spaces and/or commas. +# Valid values for version_path_separator are: +# +# version_path_separator = : +# version_path_separator = ; +# version_path_separator = space +# version_path_separator = newline +version_path_separator = os # Use os.pathsep. Default configuration used for new projects. + +# set to 'true' to search source files recursively +# in each "version_locations" directory +# new in Alembic version 1.10 +# recursive_version_locations = false + +# the output encoding used when revision files +# are written from script.py.mako +# output_encoding = utf-8 + +sqlalchemy.url = yql+ydb://localhost:2136/local + + +[post_write_hooks] +# post_write_hooks defines scripts or Python functions that are run +# on newly generated revision scripts. See the documentation for further +# detail and examples + +# format using "black" - use the console_scripts runner, against the "black" entrypoint +# hooks = black +# black.type = console_scripts +# black.entrypoint = black +# black.options = -l 79 REVISION_SCRIPT_FILENAME + +# lint with attempts to fix using "ruff" - use the exec runner, execute a binary +# hooks = ruff +# ruff.type = exec +# ruff.executable = %(here)s/.venv/bin/ruff +# ruff.options = --fix REVISION_SCRIPT_FILENAME + +# Logging configuration +[loggers] +keys = root,sqlalchemy,alembic + +[handlers] +keys = console + +[formatters] +keys = generic + +[logger_root] +level = WARNING +handlers = console +qualname = + +[logger_sqlalchemy] +level = WARNING +handlers = +qualname = sqlalchemy.engine + +[logger_alembic] +level = INFO +handlers = +qualname = alembic + +[handler_console] +class = StreamHandler +args = (sys.stderr,) +level = NOTSET +formatter = generic + +[formatter_generic] +format = %(levelname)-5.5s [%(name)s] %(message)s +datefmt = %H:%M:%S diff --git a/examples/alembic/migrations/README b/examples/alembic/migrations/README new file mode 100644 index 0000000..98e4f9c --- /dev/null +++ b/examples/alembic/migrations/README @@ -0,0 +1 @@ +Generic single-database configuration. \ No newline at end of file diff --git a/examples/alembic/migrations/env.py b/examples/alembic/migrations/env.py new file mode 100644 index 0000000..c812e8a --- /dev/null +++ b/examples/alembic/migrations/env.py @@ -0,0 +1,95 @@ +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() diff --git a/examples/alembic/migrations/script.py.mako b/examples/alembic/migrations/script.py.mako new file mode 100644 index 0000000..fbc4b07 --- /dev/null +++ b/examples/alembic/migrations/script.py.mako @@ -0,0 +1,26 @@ +"""${message} + +Revision ID: ${up_revision} +Revises: ${down_revision | comma,n} +Create Date: ${create_date} + +""" +from typing import Sequence, Union + +from alembic import op +import sqlalchemy as sa +${imports if imports else ""} + +# revision identifiers, used by Alembic. +revision: str = ${repr(up_revision)} +down_revision: Union[str, None] = ${repr(down_revision)} +branch_labels: Union[str, Sequence[str], None] = ${repr(branch_labels)} +depends_on: Union[str, Sequence[str], None] = ${repr(depends_on)} + + +def upgrade() -> None: + ${upgrades if upgrades else "pass"} + + +def downgrade() -> None: + ${downgrades if downgrades else "pass"} diff --git a/examples/alembic/migrations/versions/820b994ffa7c_create_seasons_table.py b/examples/alembic/migrations/versions/820b994ffa7c_create_seasons_table.py new file mode 100644 index 0000000..f50d306 --- /dev/null +++ b/examples/alembic/migrations/versions/820b994ffa7c_create_seasons_table.py @@ -0,0 +1,37 @@ +"""create seasons table + +Revision ID: 820b994ffa7c +Revises: d91d9200b65c +Create Date: 2024-12-10 14:50:44.633728 + +""" +from typing import Sequence, Union + +from alembic import op +import sqlalchemy as sa + + +# revision identifiers, used by Alembic. +revision: str = '820b994ffa7c' +down_revision: Union[str, None] = 'd91d9200b65c' +branch_labels: Union[str, Sequence[str], None] = None +depends_on: Union[str, Sequence[str], None] = None + + +def upgrade() -> None: + # ### commands auto generated by Alembic - please adjust! ### + op.create_table('seasons', + sa.Column('series_id', sa.Integer(), nullable=False), + sa.Column('season_id', sa.Integer(), nullable=False), + sa.Column('title', sa.Unicode(), nullable=True), + sa.Column('first_aired', sa.Integer(), nullable=True), + sa.Column('last_aired', sa.Integer(), nullable=True), + sa.PrimaryKeyConstraint('series_id', 'season_id') + ) + # ### end Alembic commands ### + + +def downgrade() -> None: + # ### commands auto generated by Alembic - please adjust! ### + op.drop_table('seasons') + # ### end Alembic commands ### diff --git a/examples/alembic/migrations/versions/9085c679f5dc_create_episodes_table.py b/examples/alembic/migrations/versions/9085c679f5dc_create_episodes_table.py new file mode 100644 index 0000000..65c158b --- /dev/null +++ b/examples/alembic/migrations/versions/9085c679f5dc_create_episodes_table.py @@ -0,0 +1,37 @@ +"""create episodes table + +Revision ID: 9085c679f5dc +Revises: 820b994ffa7c +Create Date: 2024-12-10 14:51:18.441037 + +""" +from typing import Sequence, Union + +from alembic import op +import sqlalchemy as sa + + +# revision identifiers, used by Alembic. +revision: str = '9085c679f5dc' +down_revision: Union[str, None] = '820b994ffa7c' +branch_labels: Union[str, Sequence[str], None] = None +depends_on: Union[str, Sequence[str], None] = None + + +def upgrade() -> None: + # ### commands auto generated by Alembic - please adjust! ### + op.create_table('episodes', + sa.Column('series_id', sa.Integer(), nullable=False), + sa.Column('season_id', sa.Integer(), nullable=False), + sa.Column('episode_id', sa.Integer(), nullable=False), + sa.Column('title', sa.Unicode(), nullable=True), + sa.Column('air_date', sa.Integer(), nullable=True), + sa.PrimaryKeyConstraint('series_id', 'season_id', 'episode_id') + ) + # ### end Alembic commands ### + + +def downgrade() -> None: + # ### commands auto generated by Alembic - please adjust! ### + op.drop_table('episodes') + # ### end Alembic commands ### diff --git a/examples/alembic/migrations/versions/d91d9200b65c_create_series_table.py b/examples/alembic/migrations/versions/d91d9200b65c_create_series_table.py new file mode 100644 index 0000000..d64b503 --- /dev/null +++ b/examples/alembic/migrations/versions/d91d9200b65c_create_series_table.py @@ -0,0 +1,36 @@ +"""create series table + +Revision ID: d91d9200b65c +Revises: +Create Date: 2024-12-10 14:50:07.017763 + +""" +from typing import Sequence, Union + +from alembic import op +import sqlalchemy as sa + + +# revision identifiers, used by Alembic. +revision: str = 'd91d9200b65c' +down_revision: Union[str, None] = None +branch_labels: Union[str, Sequence[str], None] = None +depends_on: Union[str, Sequence[str], None] = None + + +def upgrade() -> None: + # ### commands auto generated by Alembic - please adjust! ### + op.create_table('series', + sa.Column('series_id', sa.Integer(), nullable=False), + sa.Column('title', sa.Unicode(), nullable=True), + sa.Column('series_info', sa.Unicode(), nullable=True), + sa.Column('release_date', sa.Integer(), nullable=True), + sa.PrimaryKeyConstraint('series_id') + ) + # ### end Alembic commands ### + + +def downgrade() -> None: + # ### commands auto generated by Alembic - please adjust! ### + op.drop_table('series') + # ### end Alembic commands ### diff --git a/examples/alembic/models.py b/examples/alembic/models.py new file mode 100644 index 0000000..09f1882 --- /dev/null +++ b/examples/alembic/models.py @@ -0,0 +1,33 @@ +import sqlalchemy.orm as orm +from sqlalchemy import Column, Integer, Unicode + +Base = orm.declarative_base() + + +class Series(Base): + __tablename__ = "series" + + series_id = Column(Integer, primary_key=True) + title = Column(Unicode) + series_info = Column(Unicode) + release_date = Column(Integer) + + +class Seasons(Base): + __tablename__ = "seasons" + + series_id = Column(Integer, primary_key=True) + season_id = Column(Integer, primary_key=True) + title = Column(Unicode) + first_aired = Column(Integer) + last_aired = Column(Integer) + + +class Episodes(Base): + __tablename__ = "episodes" + + series_id = Column(Integer, primary_key=True) + season_id = Column(Integer, primary_key=True) + episode_id = Column(Integer, primary_key=True) + title = Column(Unicode) + air_date = Column(Integer) diff --git a/tox.ini b/tox.ini index 494bf2b..a97c090 100644 --- a/tox.ini +++ b/tox.ini @@ -69,4 +69,4 @@ ignore=E203,W503 per-file-ignores = ydb_sqlalchemy/__init__.py: F401 ydb_sqlalchemy/sqlalchemy/compiler/__init__.py: F401 -exclude=*_pb2.py,*_grpc.py,.venv,.git,.tox,dist,doc,*egg,docs/* +exclude=*_pb2.py,*_grpc.py,.venv,.git,.tox,dist,doc,*egg,docs/*,examples/alembic/*