.. title:: JSON Logging

JSON Logging
============

The library supports outputting JSON-structured logs to either the console or a file. To utilize this feature, you need to use named arguments within the format string, specifically inside the ``{}`` placeholders, when invoking the ``LOG_`` macros.

For convenience, the ``LOGJ_`` macros offer an alternative method for logging l-values, automatically including the argument names in the placeholders. These macros support up to 20 arguments.

It is also possible to combine JSON output with standard log pattern display by passing multiple ``Sink`` objects to a ``Logger``. This allows you to see the same log message in different formats simultaneously.

Logging Json to Console
-----------------------

.. literalinclude:: ../examples/json_console_logging.cpp
   :language: cpp
   :linenos:

Logging Json to File
--------------------

.. literalinclude:: examples/quill_docs_example_json_logging.cpp
   :language: cpp
   :linenos:

Customising Json Format
-----------------------

To customize the JSON format, define a custom sink that derives from one of the following classes:

- :cpp:class:`JsonFileSink`
- :cpp:class:`JsonConsoleSink`
- :cpp:class:`RotatingJsonFileSink`

.. literalinclude:: ../examples/json_console_logging_custom_json.cpp
   :language: cpp
   :linenos:

Combining JSON and Standard Log Patterns
----------------------------------------

.. literalinclude:: ../examples/json_file_logging.cpp
   :language: cpp
   :linenos: