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author | Frédéric Mangano-Tarumi <fmang@mg0.fr> | 2020-02-22 22:31:26 +0100 |
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committer | Lukas Fleischer <lfleischer@archlinux.org> | 2020-02-27 16:44:36 +0100 |
commit | a8a1f74a9207339bf707bb09e8dba7b2c67abb5b (patch) | |
tree | e8fa6de61abc49cb8710e283b7f6661e96add849 /migrations | |
parent | 7188743fc3b1a9c1f5f65e323a6502d018bd95d5 (diff) | |
download | aur-a8a1f74a9207339bf707bb09e8dba7b2c67abb5b.tar.gz aur-a8a1f74a9207339bf707bb09e8dba7b2c67abb5b.tar.xz |
Set up Alembic for database migrations
Signed-off-by: Lukas Fleischer <lfleischer@archlinux.org>
Diffstat (limited to 'migrations')
-rw-r--r-- | migrations/README | 48 | ||||
-rw-r--r-- | migrations/env.py | 73 | ||||
-rw-r--r-- | migrations/script.py.mako | 24 |
3 files changed, 145 insertions, 0 deletions
diff --git a/migrations/README b/migrations/README new file mode 100644 index 00000000..301d0e54 --- /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"} |