Simple Log to File example for django 1.3+

Question

The release notes say:

Django 1.3 adds framework-level support for Python’s logging module.

That's nice. I'd like to take advantage of that. Unfortunately the documentation doesn't hand it all to me on a silver platter in the form of complete working example code which demonstrates how simple and valuable this is.

How do I set up this funky new feature such that I can pepper my code with

logging.debug('really awesome stuff dude: %s' % somevar)

and see the file "/tmp/application.log" fill up with

18:31:59 Apr 21 2011 awesome stuff dude: foobar
18:32:00 Apr 21 2011 awesome stuff dude: foobar
18:32:01 Apr 21 2011 awesome stuff dude: foobar

What's the difference between the default Python logging and this 'framework-level support'?

Answer 1

Based partially on the logging config suggested by rh0dium and some more research I did myself, I started assembling an example Django project with nice logging defaults – fail-nicely-django.

Sample logfile output:

2016-04-05 22:12:32,984 [Thread-1    ] [INFO ] [djangoproject.logger]  This is a manually logged INFO string.
2016-04-05 22:12:32,984 [Thread-1    ] [DEBUG] [djangoproject.logger]  This is a manually logged DEBUG string.
2016-04-05 22:12:32,984 [Thread-1    ] [ERROR] [django.request      ]  Internal Server Error: /
Traceback (most recent call last):
  File "/Users/kermit/.virtualenvs/fail-nicely-django/lib/python3.5/site-packages/django/core/handlers/base.py", line 149, in get_response
    response = self.process_exception_by_middleware(e, request)
  File "/Users/kermit/.virtualenvs/fail-nicely-django/lib/python3.5/site-packages/django/core/handlers/base.py", line 147, in get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/Users/kermit/projekti/git/fail-nicely-django/djangoproject/brokenapp/views.py", line 12, in brokenview
    raise Exception('This is an exception raised in a view.')
Exception: This is an exception raised in a view.

The detailed usage is explained in the README, but essentially, you copy the logger module to your Django project and add from .logger import LOGGING at the bottom of your settings.py.

Answer 2

I truly love this so much here is your working example! Seriously this is awesome!

Start by putting this in your settings.py

LOGGING = {
    'version': 1,
    'disable_existing_loggers': True,
    'formatters': {
        'standard': {
            'format' : "[%(asctime)s] %(levelname)s [%(name)s:%(lineno)s] %(message)s",
            'datefmt' : "%d/%b/%Y %H:%M:%S"
        },
    },
    'handlers': {
        'null': {
            'level':'DEBUG',
            'class':'django.utils.log.NullHandler',
        },
        'logfile': {
            'level':'DEBUG',
            'class':'logging.handlers.RotatingFileHandler',
            'filename': SITE_ROOT + "/logfile",
            'maxBytes': 50000,
            'backupCount': 2,
            'formatter': 'standard',
        },
        'console':{
            'level':'INFO',
            'class':'logging.StreamHandler',
            'formatter': 'standard'
        },
    },
    'loggers': {
        'django': {
            'handlers':['console'],
            'propagate': True,
            'level':'WARN',
        },
        'django.db.backends': {
            'handlers': ['console'],
            'level': 'DEBUG',
            'propagate': False,
        },
        'MYAPP': {
            'handlers': ['console', 'logfile'],
            'level': 'DEBUG',
        },
    }
}

Now what does all of this mean?

1. Formaters I like it to come out as the same style as ./manage.py runserver
2. Handlers - I want two logs - a debug text file, and an info console. This allows me to really dig in (if needed) and look at a text file to see what happens under the hood.
3. Loggers - Here is where we nail down what we want to log. In general django gets WARN and above - the exception (hence propagate) is the backends where I love to see the SQL calls since they can get crazy.. Last is my app were I have two handlers and push everything to it.

Now how do I enable MYAPP to use it...

Per the documentation put this at the top of your files (views.py)..

import logging
log = logging.getLogger(__name__)

Then to get something out do this.

log.debug("Hey there it works!!")
log.info("Hey there it works!!")
log.warn("Hey there it works!!")
log.error("Hey there it works!!")

Log levels are explained here and for pure python here.