Logging to file in Django > 1.3

As I'm sure you're well aware, Django 1.3 brought with it a unified way of using the Python logging module as part of your Django app/project. Before this existed, everyone had their own way to handle logging so it's great to have a pluggable interface which you can guarantee will be there provided the user is using 1.3+.

Logging to file is actually rarity for me personally these days due a couple of things: 1) using the StreamHandler to output straight to the runserver command line output and 2) because of the excellent logging Sentry can provide on production servers where you don't get to see the std output.

However, sometimes you're still in a situation where you can't use either of these or would just simply like to log to a local file because it's quick and easy. The following code in your settings.py will help with that:

LOGGING = {
    'version': 1,
    'disable_existing_loggers': False,
    'handlers': {
        'mail_admins': {
            'level': 'ERROR',
            'class': 'django.utils.log.AdminEmailHandler'
        },
        'stream_to_console': {
            'level': 'DEBUG',
            'class': 'logging.StreamHandler'
        },
        'file': {
            'level': 'DEBUG',
            'class': 'logging.FileHandler',
            'filename': here('random_log.log'),
        },
    },
    'loggers': {
        'django.request': {
            'handlers': ['mail_admins', 'stream_to_console'],
            'level': 'ERROR',
            'propagate': True,
        },
        'another_random_logger': {
            'handlers': ['file'],
            'level': 'DEBUG',
            'propagate': True,
        },
    }
}

As you can see, there are two new handlers on top of Django's 'mail_admin' default: 'stream_to_console' will log using Python's StreamHandler and therefore output to the terminal (when using runserver); and 'file' will use Python's FileHandler logger to output to the filename specified. To get your loggers to use these, their name needs to be included in the 'handlers' list of the individual loggers (also defined above - see 'another_random_logger'). I haven't used them here, but the docs detail full usage of filters and formatters.

You will notice my filename entry uses a callable to return the correct value; this is so the filename can be specified relative to the project directory as opposed to hard-coding the path in your settings file. The same function gets uses to work out STATIC/MEDIA_ROOT's etc; hard-coding that kind of absolute path in your settings is not advised (but may make sense if you're logging somewhere specific, say /var/log/).

The function is below for anyone wishing to use that tactic:

here = lambda *x: os.path.join(os.path.dirname(
                               os.path.realpath(__file__)), *x)
# Given the file you run this is located in
# /home/djm/projects/some_project/ this
# will give you the following:
>>> here('some_log.log')
/home/djm/projects/some_project/some_log.log
>>> here('..', '..', 'some_log.log')
/home/djm/some_log.log

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