.. _installation_prerequisites:

Prerequisites
=============

Open Zaak is most often deployed as a Docker container. While the
`container images <https://hub.docker.com/r/openzaak/open-zaak/>`_ contain all the
necessary dependencies, Open Zaak does require extra service to deploy the full stack.
These dependencies and their supported versions are documented here.

The ``docker-compose.yml`` (not suitable for production usage!) in the root of the
repository also describes these dependencies.

PostgreSQL with Postgis
-----------------------

.. warning::

   Since Open Zaak version 1.21.0, PostgreSQL version 14 or higher is required. Attempting
   to deploy this version of Open Zaak with PostgreSQL 13 or lower will result in errors!

Open Zaak currently only supports PostgreSQL as datastore. The Zaken API are geo-capable,
which requires the postgis_ extension to be enabled.

The supported versions in the table below are tested in the CI pipeline. Other versions
*may* work but we offer no guarantees.

============ ============ ============ ============ ============
Matrix       Postgres 14  Postgres 15  Postgres 16  Postgres 17
============ ============ ============ ============ ============
Postgis 3.2  V            X            X            X
Postgis 3.5  V            V            V            V
============ ============ ============ ============ ============

.. warning:: Open Zaak only supports maintained versions of PostgreSQL. Once a version is
   `EOL <https://www.postgresql.org/support/versioning/>`_, support will
   be dropped in the next release.

.. _postgis: https://postgis.net/

Redis
-----

Open Zaak uses Redis as a cache backend, especially relevant for admin sessions, and as
task queue broker.

Supported versions: 5, 6, 7.

Reverse proxy (nGINX)
---------------------

The Open Zaak Documents API serves uploaded files after verifying the permissions. The
actual file-serving is delegated to the reverse proxy through the ``X-Sendfile``
feature. By default, Open Zaak is configured for nGINX and will emit the ``X-Accel``
header.

You can use alternative reverse proxy implementations and configure this through the
``SENDFILE_BACKEND`` environment variable. See the
`django-sendfile2 <https://django-sendfile2.readthedocs.io/en/latest/backends.html>`_
documentation for available backends.


.. note:: If you are not using the Open Zaak Documents API, but an alternative
   implementation, then this requirement becomes obsolete.