docs/reference/persister.rst

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=================
State Persistence
=================

.. _persistersref:

Burr provides a set of tools to make loading and saving state easy. These are functions
that will be used by lifecycle hooks to save and load state.

We currently support the following database integrations:

.. table:: Burr Implemented Persisters
    :widths: auto

    +-------------+-----------------------------------------------------------------+---------------------------------------------------------------------+
    | Database    | Sync                                                            | Async                                                               |
    +=============+===========+=====================================================+===============+=====================================================+
    | SQLite      | sqlite3   | :ref:`SQLitePersister <syncsqliteref>`              | aiosqlite     | :ref:`AsyncSQLitePersister <asyncsqliteref>`        |
    +-------------+-----------+-----------------------------------------------------+---------------+-----------------------------------------------------+
    | PostgreSQL  | psycopg2  | :ref:`PostgreSQLPersister <syncpostgresref>`        | asyncpg       | :ref:`AsyncPostgreSQLPersister <asyncpostgresref>`  |
    +-------------+-----------+-----------------------------------------------------+---------------+-----------------------------------------------------+
    | Redis       | redis     | :ref:`RedisBasePersister <syncredisref>`            | redis.asyncio | :ref:`AsyncRedisBasePersister <asyncredisref>`      |
    +-------------+-----------+-----------------------------------------------------+---------------+-----------------------------------------------------+
    | MongoDB     | pymongo   | :ref:`MongoDBBasePersister <syncmongoref>`          | ❌            | ❌                                                  |
    +-------------+-----------+-----------------------------------------------------+---------------+-----------------------------------------------------+

We follow the naming convention ``b_dependency-library``, where the ``b_`` is used to avoid name
clashing with the underlying library. We chose the library name in case we implement the same database
persister with different dependency libraries to keep the class naming convention.

If you want to implement your own state persister (to bridge it with a database), you should implement
the ``BaseStatePersister`` or the ``AsyncBaseStatePersister`` interface.

.. autoclass:: burr.core.persistence.BaseStatePersister
   :members:
   :show-inheritance:
   :inherited-members:

   .. automethod:: __init__

Internally, this interface combines the following two interfaces:

.. autoclass:: burr.core.persistence.BaseStateLoader
   :members:

   .. automethod:: __init__

.. autoclass:: burr.core.persistence.BaseStateSaver
    :members:
    :show-inheritance:
    :inherited-members:

    .. automethod:: __init__

Note we also have the corresponding async implementations:

.. autoclass:: burr.core.persistence.AsyncBaseStatePersister
   :members:
   :show-inheritance:
   :inherited-members:

   .. automethod:: __init__

Internally, this interface combines the following two interfaces:

.. autoclass:: burr.core.persistence.AsyncBaseStateLoader
   :members:

   .. automethod:: __init__

.. autoclass:: burr.core.persistence.AsyncBaseStateSaver
    :members:
    :show-inheritance:
    :inherited-members:

    .. automethod:: __init__



Supported Sync Implementations
================================

Currently we support the following, although we highly recommend you contribute your own! We will be adding more shortly.

.. _syncsqliteref:

.. autoclass:: burr.core.persistence.SQLitePersister
   :members:

   .. automethod:: __init__

.. _syncpostgresref:

.. autoclass:: burr.integrations.persisters.b_psycopg2.PostgreSQLPersister
   :members:

   .. automethod:: __init__

.. _syncredisref:

.. autoclass:: burr.integrations.persisters.b_redis.RedisBasePersister
   :members:

   .. automethod:: __init__

.. _syncmongoref:

.. autoclass:: burr.integrations.persisters.b_pymongo.MongoDBBasePersister
   :members:

   .. automethod:: __init__


Note that the :py:class:`LocalTrackingClient <burr.tracking.client.LocalTrackingClient>` leverages the :py:class:`BaseStateLoader <burr.core.persistence.BaseStateLoader>` to allow loading state,
although it uses different mechanisms to save state (as it tracks more than just state).


Supported Async Implementations
================================

.. _asyncpersistersref:

Currently we support the following, although we highly recommend you contribute your own! We will be adding more shortly.

.. _asyncsqliteref:

.. autoclass:: burr.integrations.persisters.b_aiosqlite.AsyncSQLitePersister
   :members:

   .. automethod:: __init__

.. _asyncpostgresref:

.. autoclass:: burr.integrations.persisters.b_asyncpg.AsyncPostgreSQLPersister
   :members:

   .. automethod:: __init__

.. _asyncredisref:

.. autoclass:: burr.integrations.persisters.b_redis.AsyncRedisBasePersister
   :members:

   .. automethod:: __init__