Django is a powerful web framework for Python that makes it easy to build web applications quickly. One important aspect of any web application is logging, which allows you to track events and errors that occur while the application is running. Django provides a built-in logging system that is flexible and easy to use.

To use the Django logging system, you will first need to configure it in your Django settings file. You can specify the logging level, the format of the log messages, and the location of the log file. For example:

LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'verbose': {
            'format': '%(levelname)s %(asctime)s %(module)s %(process)d %(thread)d %(message)s'
        },
        'simple': {
            'format': '%(levelname)s %(message)s'
        },
    },
    'handlers': {
        'file': {
            'level': 'DEBUG',
            'class': 'logging.FileHandler',
            'filename': '/path/to/django.log',
            'formatter': 'verbose'
        },
    },
    'loggers': {
        'django': {
            'handlers': ['file'],
            'level': 'DEBUG',
            'propagate': True,
        },
    },
}

Once you have configured the logging system, you can use the logger object in your Django code to log messages. For example:

import logging

logger = logging.getLogger(__name__)

def view_function(request):
    logger.debug("Received request from %s", request.user.username)
    # ...

You can also use the logging module directly to log messages at different levels, such as debug, info, warning, error, and critical.

In addition to logging messages, Django also provides support for logging errors using the exception method of the logger. This will automatically log the stack trace along with the error message.

try:
    # code that may throw an exception
except Exception as e:
    logger.exception("An error occurred: %s", e)

It is important to keep in mind that the Django logging system is separate from the system logs on the server. You should not use the Django logging system to log system-level events such as server startup and shutdown, as this information should be logged by the operating system.

Overall, the Django logging system is a powerful and flexible tool that can help you track events and errors in your web application. By configuring the logging system and using the logger object or the logging module, you can easily log messages and exceptions to help debug and understand what is happening in your application.