kallithea Files · docs/dev/dbmigrations.rst

Files @ e71216a16853

Branch filter:

Location: kallithea/docs/dev/dbmigrations.rst

e71216a16853 2.9 KiB text/prs.fallenstein.rst Show Annotation Show as Raw Download as Raw

Thomas De Schampheleire

docs: reorganize index page

Reorganize the index page of the manual into three main sections:
administrator guide, user guide, developer guide. In principle,
administrators, users and developers are independent roles that can be
fulfilled by different people.

'Administrators' install, configure and maintain Kallithea. They have
'admin' privilege in the web interface.

'Users' do not have access to the Kallithea installation files. They can
only access the web interface, and generally do not have 'admin' privilege.
They may be the owner of repositories, repository groups, or user groups,
and as such modify the settings of these objects, even though they cannot
modify the settings of Kallithea itself.

'Developers' modify the Kallithea source code. They may or may not
contribute these changes back to the Kallithea community.

The 'Readme' section is a bit outside of this classification. As it serves
as a basic introduction to Kallithea, it is kept first.

The 'Index' and 'Search' functionality are not really 'part of' the manual,
so should not be under 'Other topics'. Instead they are put at the very top
so they are readily visible.

This commit is only changing the index page. Subsequent commits can move and
split some documentation files in the repository to mirror this structure.
For example, the 'Version control systems support' page has information for
administrators (ini settings and importing existing repositories) as well as
for users (handling Mercurial subrepositories).

=======================
Database schema changes
=======================

Kallithea uses Alembic for :ref:`database migrations <upgrade_db>`
(upgrades and downgrades).

If you are developing a Kallithea feature that requires database schema
changes, you should make a matching Alembic database migration script:

1. :ref:`Create a Kallithea configuration and database <setup>` 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.)

2. Create a separate throwaway configuration for iterating on the actual
   database changes::

    gearbox make-config 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.

3. Make your code changes (including database schema changes in ``db.py``).

4. After every database schema change, recreate the throwaway database
   to test the changes::

    rm temp.db
    gearbox setup-db -c temp.ini --repos=/var/repos --user=doe --email doe@example.com --password=123456 --no-public-access --force-yes
    gearbox repo-scan -c temp.ini

5. 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

6. 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.

7. 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 setting ``level = 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.

.. __: http://alembic.zzzcomputing.com/en/latest/


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).