Setup Logger in Django 1.3 to show warning & error in console development

New guys in Django commonly have a headache to see Logger configuration in settings.py. Sometimes people only want use Logger to print error / warning / debug in server development. Here are how to do that.

First, open up your settings.py and see at logger section :

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There are two part that you should know, Handler and Loggers. Basically, this is python logging configuration. Really? you can read at http://docs.python.org/library/logging.config.html#configuration-dictionary-schema.

1. Handlers

This will handling incoming loggers. As defined in python logging config :

the handler with id console is instantiated as a logging.StreamHandler, using sys.stdout as the underlying stream

So, we create console handlers by :

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‘handlers’: {
‘mail_admins’: {
‘level’: ‘ERROR’,
‘class’: ‘django.utils.log.AdminEmailHandler’
},
‘console’: {
‘level’: ‘DEBUG’,
‘class’: ‘logging.StreamHandler’,
‘formatter’: ‘verbose’
},
},

2. Formatter

Wait, I see formatter here called “verbose”. What it is? Actually it’s about formatting print out logger result. For instance, you have :

1	msg = logger.error("Some error")

If there no formatter it will return “Some error”. But we want to show informative log, like :

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<level> <time> <module> <message>

# Will produce:
ERROR 2012-03-22 11:17:19 views Some error

There are two example for formatter here :

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formatters’: {
‘verbose’: {
‘format’: ‘%(levelname)s %(asctime)s %(module)s %(process)d %(thread)d %(message)s’
},
‘simple’: {
‘format’: ‘%(levelname)s %(asctime)s %(module)s %(message)s’
},
},

3. Logger

Then, the last thing is Logger, which we create name of logger and use console as handlers.

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‘loggers’: {
‘django.request’: {
‘handlers’: [‘mail_admins’],
‘level’: ‘ERROR’,
‘propagate’: True,
},
‘app’: {
‘handlers’: [‘console’],
‘level’: ‘DEBUG’,
‘propagate’: True,
},
}

All of code :

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# A sample logging configuration. The only tangible logging
# performed by this configuration is to send an email to
# the site admins on every HTTP 500 error.
# See http://docs.djangoproject.com/en/dev/topics/logging for
# more details on how to customize your logging configuration.
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 %(asctime)s %(module)s %(message)s’
},
},
‘handlers’: {
‘mail_admins’: {
‘level’: ‘ERROR’,
‘class’: ‘django.utils.log.AdminEmailHandler’
},
‘console’: {
‘level’: ‘DEBUG’,
‘class’: ‘logging.StreamHandler’,
‘formatter’: ‘verbose’
},
},
‘loggers’: {
‘django.request’: {
‘handlers’: [‘mail_admins’],
‘level’: ‘ERROR’,
‘propagate’: True,
},
‘app’: {
‘handlers’: [‘console’],
‘level’: ‘DEBUG’,
‘propagate’: True,
},
}
}

Now we are ready to test-drive. For example, run django server development. Then, choose some views.py and test your logger using “app” as logger.

Eg : views.py

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from django.shortcuts import render

from django.utils.log import getLogger
logger = getLogger(‘app’)

def index(request):
logger.warning("This is warning")
logger.error("This is error")
return render(request, ‘web/index.html’)

Also make sure your enable DEBUG in settings.py. Now, you can see that logger show up in the console 🙂

For more detail explanation, you should read :
https://docs.djangoproject.com/en/dev/topics/logging/

Some advanced example :
https://gist.github.com/887364

Yodi Aditya

Setup Logger in Django 1.3 to show warning & error in console development

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