Introduction:

We have seen how to set up loggers with Django and print messages to a log file. Sometimes, we want to print the messages into separate log files based on the message's origin (which app).

In this tutorial, we will see how to print each Django app’s message to a separate log file.

Flow Diagram:

Prerequisites:

Python 3.8

Django Project

Steps:

Step 1: Configure loggers with Django

In case you didn’t have a Django application configured with the logger, please refer to the following article Logging with Django.

Step 2: Define Handlers

First, we need to create handlers for each app in our Django application, so that we can point the loggers created for each app to the corresponding handlers.

In my case, I’m having two apps named log_app and example_app, so I’m creating two handlers named log_app_handler and example_app_handler as in the following snippet.

Navigate to the Django project directory and update the settings.py file with the following contents.

'handlers': {
        'log_app_handler': {
            'level': 'DEBUG',
            'class': 'logging.FileHandler',
            'filename': '<django_project_directory>/log_app.log',
            'formatter': 'verbose'
        },
        'example_app_handler': {
            'level': 'DEBUG',
            'class': 'logging.FileHandler',
            'filename': '<django_project_directory>/example_app.log',
            'formatter': 'verbose'
        },
    },

Step 3: Define loggers

Now we need to create loggers for each app and associate their respective handlers as in the following snippet.

'loggers': {
        'log_app':{
            'level': 'DEBUG',
            'handlers': ['log_app_handler'],
            'propagate': False,
        },
        'example_app':{
            'level': 'DEBUG',
            'handlers': ['example_app_handler'],
            'propagate': False,
        },
    },

Now the logger configuration will look like in the following example code snippet.

LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'formatters': {
        'verbose': {
            'format': '{levelname} {asctime} {module} {process:d} {thread:d} {message}',
            'style': '{',
        },
    },
    'handlers': {
        'log_app_handler': {
            'level': 'DEBUG',
            'class': 'logging.FileHandler',
            'filename': '/home/ubuntu/django_logger_example/log_app.log',
            'formatter': 'verbose'
        },
        'example_app_handler': {
            'level': 'DEBUG',
            'class': 'logging.FileHandler',
            'filename': '/home/ubuntu/django_logger_example/example_app.log',
            'formatter': 'verbose'
        },
    },
    'loggers': {
        'log_app':{
            'level': 'DEBUG',
            'handlers': ['log_app_handler'],
            'propagate': False,
        },
        'example_app':{
            'level': 'DEBUG',
            'handlers': ['example_app_handler'],
            'propagate': True,
        },
    },
}

An example settings.py file can be found in the following git repo: https://github.com/episyche/django_app_based_loggers_example/blob/master/core/settings.py

Step 4: Checking logs

We have created separate loggers and handlers the logs are pushed to separate files.

Save the configuration and start the Django application.

In a new terminal, navigate to the Django project directory and tail the log file of the log_app by running the following command.

cd /home/ubuntu/django_logger_example
tail -f log_app.log

Now the logs of the log_app are shown in the terminal.

In a different terminal, navigate to the Django project directory and tail the log file of the example_app by running the following command.

cd /home/ubuntu/django_logger_example
tail -f example_app.log

Now the logs of the example_app are shown in the terminal.

Note: You can find the full source code for configuring multiple loggers can be found at the following GitHub repo: https://github.com/episyche/django_app_based_loggers_example.git

Multiple loggers in Django