Debugging Weblate
=================

Bugs can behave as application crashes or as various misbehavior.
You are welcome to collect info on any such issue and submit it to the `issue tracker
<https://github.com/WeblateOrg/weblate/issues>`_.

Debug mode
----------

Turning on debug mode will make the exceptions show in the web browser. This is useful to
debug issues in the web interface, but not suitable for a production environment
because it has performance consequences and might leak private data.

In a production environment, use :setting:`ADMINS` to receive e-mails containing error
reports, or configure error collection using a third-party service.

.. seealso::

   :ref:`production-debug`,
   :ref:`production-admins`,
   :ref:`collecting-errors`

.. _weblate-logs:

Weblate logs
------------

Weblate can produce detailed logs of what is going on in the background.
In the default configuration it uses syslog and that makes the log appear either in
:file:`/var/log/messages` or :file:`/var/log/syslog` (depending on your syslog
daemon configuration).

The Celery process (see :ref:`celery`) usually produces its own logs as well.
The example system-wide setups logs to several files under :file:`/var/log/celery/`.

Docker containers log to their output (as per usual in the Docker world), so
you can look at the logs using ``docker-compose logs``.

.. seealso::

   :ref:`sample-configuration` contains :setting:`django:LOGGING` configuration.

.. _debug-tasks:

Not processing background tasks
-------------------------------

A lot of things are done in the background by Celery workers.
If things like sending out e-mails or component removal does not work,
there might a related issue.

Things to check in that case:

* Check that the Celery process is running, see :ref:`celery`
* Check the Celery queue status, either in :ref:`management-interface`, or using :djadmin:`celery_queues`
* Look in the Celery logs for errors (see :ref:`weblate-logs`)

.. _debug-mails:

Not receiving e-mails from Weblate
----------------------------------

You can verify whether outgoing e-mail is working correctly by using the
:djadmin:`django:sendtestemail` management command (see :ref:`invoke-manage`
for instructions on how to invoke it in different environments) or by using
:ref:`management-interface` under the :guilabel:`Tools` tab.

These send e-mails directly, so this verifies that your SMTP configuration is
correct (see :ref:`out-mail`).
Most of the e-mails from Weblate are however sent in the background and there might
be some issues with Celery involved as well, please see :ref:`debug-tasks` for debugging that.

Analyzing application crashes
-----------------------------

In case the application crashes, it is useful to collect as much info about
the crash as possible.
This can be achieved by using third-party services which can collect such info automatically.
You can find info on how to set this up in :ref:`collecting-errors`.

Silent failures
---------------

Lots of tasks are offloaded to Celery for background processing.
Failures are not shown in the user interface, but appear in the Celery logs.
Configuring :ref:`collecting-errors` helps you to notice such failures easier.

Performance issues
------------------

In case Weblate performs badly in some scenario, please collect the relevant logs
showing the issue, and anything that might help figuring out where the code might be
improved.

In case some requests take too long without any indication, you might
want to install `dogslow <https://pypi.org/project/dogslow/>`_ along with
:ref:`collecting-errors` and get pinpointed and detailed tracebacks in
the error collection tool.

In case the slow performance is linked to the database, you can also enable
logging of all database queries using following configuration after enabling
:setting:`DEBUG`:

.. code-block:: python

   LOGGING["loggers"]["django.db.backends"] = {"handlers": ["console"], "level": "DEBUG"}
