Database schema changes¶
Kallithea uses Alembic for database migrations (upgrades and downgrades).
If you are developing a Kallithea feature that requires database schema changes, you should make a matching Alembic database migration script:
Create a Kallithea configuration and database for testing the migration script, or use existing
development.ini
setup.Ensure that this database is up to date with the latest database schema before the changes you’re currently developing. (Do not create the database while your new schema changes are applied.)
Create a separate throwaway configuration for iterating on the actual database changes:
kallithea-cli config-create temp.ini
Edit the file to change database settings. SQLite is typically fine, but make sure to change the path to e.g.
temp.db
, to avoid clobbering any existing database file.Make your code changes (including database schema changes in
db.py
).After every database schema change, recreate the throwaway database to test the changes:
rm temp.db kallithea-cli db-create -c temp.ini --repos=/var/repos --user=doe --email doe@example.com --password=123456 --no-public-access --force-yes kallithea-cli repo-scan -c temp.ini
Once satisfied with the schema changes, auto-generate a draft Alembic script using the development database that has not been upgraded. (The generated script will upgrade the database to match the code.)
alembic -c development.ini revision -m "area: add cool feature" --autogenerate
Edit the script to clean it up and fix any problems.
Note that for changes that simply add columns, it may be appropriate to not remove them in the downgrade script (and instead do nothing), to avoid the loss of data. Unknown columns will simply be ignored by Kallithea versions predating your changes.
Run
alembic -c development.ini upgrade head
to apply changes to the (non-throwaway) database, and test the upgrade script. Also test downgrades.The included
development.ini
has full SQL logging enabled. If you’re using another configuration file, you may want to enable it by settinglevel = DEBUG
in section[handler_console_sql]
.
The Alembic migration script should be committed in the same revision as
the database schema (db.py
) changes.
See the Alembic documentation for more information, in particular the tutorial and the section about auto-generating migration scripts.
Troubleshooting¶
- If
alembic --autogenerate
responds “Target database is not up to date”, you need to either first use Alembic to upgrade the database to the most recent version (before your changes), or recreate the database from scratch (without your schema changes applied).