--- INSTALL | 4 +- TESTING | 3 +- alembic.ini | 86 +++++++++++++++++++++++++++++++++++++++ aurweb/initdb.py | 9 ++++ aurweb/schema.py | 8 ++++ migrations/README | 48 ++++++++++++++++++++++ migrations/env.py | 73 +++++++++++++++++++++++++++++++++ migrations/script.py.mako | 24 +++++++++++ 8 files changed, 252 insertions(+), 3 deletions(-) create mode 100644 alembic.ini create mode 100644 migrations/README create mode 100644 migrations/env.py create mode 100644 migrations/script.py.mako diff --git a/INSTALL b/INSTALL index 68fe5dcd..7087aca2 100644 --- a/INSTALL +++ b/INSTALL @@ -47,8 +47,8 @@ read the instructions below. 4) Install Python modules and dependencies: - # pacman -S python-mysql-connector python-pygit2 python-srcinfo python-sqlalchemy - # pacman -S python-bleach python-markdown + # pacman -S python-mysql-connector python-pygit2 python-srcinfo python-sqlalchemy \ + python-bleach python-markdown python-alembic # python3 setup.py install 5) Create a new MySQL database and a user and import the aurweb SQL schema: diff --git a/TESTING b/TESTING index 190043f9..4a1e6f4c 100644 --- a/TESTING +++ b/TESTING @@ -11,7 +11,8 @@ INSTALL. 2) Install the necessary packages: - # pacman -S --needed php php-sqlite sqlite words fortune-mod python python-sqlalchemy + # pacman -S --needed php php-sqlite sqlite words fortune-mod \ + python python-sqlalchemy python-alembic Ensure to enable the pdo_sqlite extension in php.ini. diff --git a/alembic.ini b/alembic.ini new file mode 100644 index 00000000..6d3a3929 --- /dev/null +++ b/alembic.ini @@ -0,0 +1,86 @@ +# A generic, single database configuration. + +[alembic] +# path to migration scripts +script_location = migrations + +# template used to generate migration files +# file_template = %%(rev)s_%%(slug)s + +# timezone to use when rendering the date +# within the migration file as well as the filename. +# string value is passed to dateutil.tz.gettz() +# 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 alembic/versions. When using multiple version +# directories, initial revisions must be specified with --version-path +# version_locations = %(here)s/bar %(here)s/bat alembic/versions + +# the output encoding used when revision files +# are written from script.py.mako +# output_encoding = utf-8 + +# the database URL is generated in env.py +# sqlalchemy.url = driver://user:pass@localhost/dbname + + +[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 + +# Logging configuration +[loggers] +keys = root,sqlalchemy,alembic + +[handlers] +keys = console + +[formatters] +keys = generic + +[logger_root] +level = WARN +handlers = console +qualname = + +[logger_sqlalchemy] +level = WARN +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/aurweb/initdb.py b/aurweb/initdb.py index e3e96503..c02fb961 100644 --- a/aurweb/initdb.py +++ b/aurweb/initdb.py @@ -1,6 +1,8 @@ import aurweb.db import aurweb.schema +import alembic.command +import alembic.config import argparse import sqlalchemy @@ -31,10 +33,17 @@ def feed_initial_data(conn): def run(args): + # Ensure Alembic is fine before we do the real work, in order not to fail at + # the last step and leave the database in an inconsistent state. The + # configuration is loaded lazily, so we query it to force its loading. + alembic_config = alembic.config.Config('alembic.ini') + alembic_config.get_main_option('script_location') + engine = sqlalchemy.create_engine(aurweb.db.get_sqlalchemy_url(), echo=(args.verbose >= 1)) aurweb.schema.metadata.create_all(engine) feed_initial_data(engine.connect()) + alembic.command.stamp(alembic_config, 'head') if __name__ == '__main__': diff --git a/aurweb/schema.py b/aurweb/schema.py index b1261e86..fde6512f 100644 --- a/aurweb/schema.py +++ b/aurweb/schema.py @@ -1,3 +1,11 @@ +""" +Schema of aurweb's database. + +Changes here should always be accompanied by an Alembic migration, which can be +usually be automatically generated. See `migrations/README` for details. +""" + + from sqlalchemy import CHAR, Column, ForeignKey, Index, MetaData, String, TIMESTAMP, Table, Text, text from sqlalchemy.dialects.mysql import BIGINT, DECIMAL, INTEGER, TINYINT from sqlalchemy.ext.compiler import compiles diff --git a/migrations/README b/migrations/README new file mode 100644 index 00000000..5c032d9b --- /dev/null +++ b/migrations/README @@ -0,0 +1,48 @@ +This directory contains Alembic’s environment for managing database migrations. + +From Alembic’s documentation: Alembic is a lightweight database migration tool +for usage with the SQLAlchemy Database Toolkit for Python. +https://alembic.sqlalchemy.org/en/latest/index.html + + +Upgrading to the latest version +------------------------------- + +Simply run `alembic upgrade head` from aurweb’s root. + + +Creating new migrations +----------------------- + +When working with Alembic and SQLAlchemy, you should never edit the database +schema manually. Please proceed like this instead: + +1. Edit `aurweb/schema.py` to your liking. +2. Run `alembic revision --autogenerate -m "your message"` +3. Proofread the generated migration. +4. Run `alembic upgrade head` to apply the changes to the database. +5. Commit the new migration. + +To revert a migration, you may run `alembic downgrade -1` and then manually +delete the migration file. Note that SQLite is limited and that it’s sometimes +easier to recreate the database. + +For anything more complicated, please read Alembic’s documentation. + + +Troubleshooting +--------------- + +- `ModuleNotFoundError: No module named 'aurweb'` + + You may either install the aurweb module with pip, or set PYTHONPATH to your + aurweb repository. Since alembic must be run from the aurweb root, you may + simply use: `PYTHONPATH=. alembic …`. + +- `FAILED: No config file 'alembic.ini' found, or file has no '[alembic]' section` + + You need to run Alembic from the project’s root, and not from `migrations/`. + +- `configparser.NoSectionError: No section: 'database'` + + You need to set AUR_CONFIG, as explained in `TESTING`. diff --git a/migrations/env.py b/migrations/env.py new file mode 100644 index 00000000..1627e693 --- /dev/null +++ b/migrations/env.py @@ -0,0 +1,73 @@ +import aurweb.db +import aurweb.schema + +from alembic import context +import logging.config +import sqlalchemy + + +# 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. +logging.config.fileConfig(config.config_file_name) + +# model MetaData for autogenerating migrations +target_metadata = aurweb.schema.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 run_migrations_offline(): + """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. + + """ + context.configure( + url=aurweb.db.get_sqlalchemy_url(), + target_metadata=target_metadata, + literal_binds=True, + dialect_opts={"paramstyle": "named"}, + ) + + with context.begin_transaction(): + context.run_migrations() + + +def run_migrations_online(): + """Run migrations in 'online' mode. + + In this scenario we need to create an Engine + and associate a connection with the context. + + """ + connectable = sqlalchemy.create_engine( + aurweb.db.get_sqlalchemy_url(), + poolclass=sqlalchemy.pool.NullPool, + ) + + with connectable.connect() as connection: + context.configure( + connection=connection, target_metadata=target_metadata + ) + + with context.begin_transaction(): + context.run_migrations() + + +if context.is_offline_mode(): + run_migrations_offline() +else: + run_migrations_online() diff --git a/migrations/script.py.mako b/migrations/script.py.mako new file mode 100644 index 00000000..2c015630 --- /dev/null +++ b/migrations/script.py.mako @@ -0,0 +1,24 @@ +"""${message} + +Revision ID: ${up_revision} +Revises: ${down_revision | comma,n} +Create Date: ${create_date} + +""" +from alembic import op +import sqlalchemy as sa +${imports if imports else ""} + +# revision identifiers, used by Alembic. +revision = ${repr(up_revision)} +down_revision = ${repr(down_revision)} +branch_labels = ${repr(branch_labels)} +depends_on = ${repr(depends_on)} + + +def upgrade(): + ${upgrades if upgrades else "pass"} + + +def downgrade(): + ${downgrades if downgrades else "pass"} -- 2.25.0