How do you log server errors on django sites
PythonDjangoError LoggingPython Problem Overview
So, when playing with the development I can just set settings.DEBUG
to True
and if an error occures I can see it nicely formatted, with good stack trace and request information.
But on kind of production site I'd rather use DEBUG=False
and show visitors some standard error 500 page with information that I'm working on fixing this bug at this moment ;)
At the same time I'd like to have some way of logging all those information (stack trace and request info) to a file on my server - so I can just output it to my console and watch errors scroll, email the log to me every hour or something like this.
What logging solutions would you recomend for a django-site, that would meet those simple requirements? I have the application running as fcgi
server and I'm using apache web server as frontend (although thinking of going to lighttpd).
Python Solutions
Solution 1 - Python
Well, when DEBUG = False
, Django will automatically mail a full traceback of any error to each person listed in the ADMINS
setting, which gets you notifications pretty much for free. If you'd like more fine-grained control, you can write and add to your settings a middleware class which defines a method named process_exception()
, which will have access to the exception that was raised:
http://docs.djangoproject.com/en/dev/topics/http/middleware/#process-exception
Your process_exception()
method can then perform whatever type of logging you'd like: writing to console, writing to a file, etc., etc.
Edit: though it's a bit less useful, you can also listen for the got_request_exception
signal, which will be sent whenever an exception is encountered during request processing:
http://docs.djangoproject.com/en/dev/ref/signals/#got-request-exception
This does not give you access to the exception object, however, so the middleware method is much easier to work with.
Solution 2 - Python
Django Sentry is a good way to go, as already mentioned, but there is a bit of work involved in setting it up properly (as a separate website). If you just want to log everything to a simple text file here's the logging configuration to put in your settings.py
LOGGING = {
'version': 1,
'disable_existing_loggers': False,
'handlers': {
# Include the default Django email handler for errors
# This is what you'd get without configuring logging at all.
'mail_admins': {
'class': 'django.utils.log.AdminEmailHandler',
'level': 'ERROR',
# But the emails are plain text by default - HTML is nicer
'include_html': True,
},
# Log to a text file that can be rotated by logrotate
'logfile': {
'class': 'logging.handlers.WatchedFileHandler',
'filename': '/var/log/django/myapp.log'
},
},
'loggers': {
# Again, default Django configuration to email unhandled exceptions
'django.request': {
'handlers': ['mail_admins'],
'level': 'ERROR',
'propagate': True,
},
# Might as well log any errors anywhere else in Django
'django': {
'handlers': ['logfile'],
'level': 'ERROR',
'propagate': False,
},
# Your own app - this assumes all your logger names start with "myapp."
'myapp': {
'handlers': ['logfile'],
'level': 'WARNING', # Or maybe INFO or DEBUG
'propagate': False
},
},
}
Solution 3 - Python
django-db-log, mentioned in another answer, has been replaced with:
Solution 4 - Python
Obviously James is correct, but if you wanted to log exceptions in a datastore, there are a few open source solutions already available:
-
CrashLog is a good choice: http://code.google.com/p/django-crashlog/
-
Db-Log is a good choice as well: http://code.google.com/p/django-db-log/
What is the difference between the two? Almost nothing that I can see, so either one will suffice.
I've used both and they work well.
Solution 5 - Python
Some time has passed since EMP's most helpful code submission. I just now implemented it, and while thrashing around with some manage.py option, to try to chase down a bug, I got a deprecation warning to the effect that with my current version of Django (1.5.?) a require_debug_false filter is now needed for the mail_admins handler.
Here is the revised code:
LOGGING = {
'version': 1,
'disable_existing_loggers': False,
'filters': {
'require_debug_false': {
'()': 'django.utils.log.RequireDebugFalse'
}
},
'handlers': {
# Include the default Django email handler for errors
# This is what you'd get without configuring logging at all.
'mail_admins': {
'class': 'django.utils.log.AdminEmailHandler',
'level': 'ERROR',
'filters': ['require_debug_false'],
# But the emails are plain text by default - HTML is nicer
'include_html': True,
},
# Log to a text file that can be rotated by logrotate
'logfile': {
'class': 'logging.handlers.WatchedFileHandler',
'filename': '/home/username/public_html/djangoprojectname/logfilename.log'
},
},
'loggers': {
# Again, default Django configuration to email unhandled exceptions
'django.request': {
'handlers': ['mail_admins'],
'level': 'ERROR',
'propagate': True,
},
# Might as well log any errors anywhere else in Django
'django': {
'handlers': ['logfile'],
'level': 'ERROR',
'propagate': False,
},
# Your own app - this assumes all your logger names start with "myapp."
'myapp': {
'handlers': ['logfile'],
'level': 'DEBUG', # Or maybe INFO or WARNING
'propagate': False
},
},
}
Solution 6 - Python
I just had an annoying problem with my fcgi
script. It occurred before django even started. The lack of logging is sooo painful. Anyway, redirecting stderr to a file as the very first thing helped a lot:
#!/home/user/env/bin/python
sys.stderr = open('/home/user/fcgi_errors', 'a')
Solution 7 - Python
You can use the logging library in Python, no need to pip install
anything.
Replace any print()
with logging.debug()
but,
> Django Sentry is a good way to go
as EMP said.