How to manage error reporting¶
When you’re running a public site you should always turn off the
DEBUG setting. That will make your server run much faster, and will
also prevent malicious users from seeing details of your application that can be
revealed by the error pages.
However, running with
DEBUG set to
False means you’ll never see
errors generated by your site – everyone will instead see your public error
pages. You need to keep track of errors that occur in deployed sites, so Django
can be configured to create reports with details about those errors.
False, Django will email the users listed in the
ADMINS setting whenever your code raises an unhandled exception and
results in an internal server error (strictly speaking, for any response with
an HTTP status code of 500 or greater). This gives the administrators immediate
notification of any errors. The
ADMINS will get a description of the
error, a complete Python traceback, and details about the HTTP request that
caused the error.
In order to send email, Django requires a few settings telling it
how to connect to your mail server. At the very least, you’ll need
EMAIL_HOST and possibly
though other settings may be also required depending on your mail
server’s configuration. Consult the Django settings
documentation for a full list of email-related
To activate this behavior, put the email addresses of the recipients in the
Server error emails are sent using the logging framework, so you can customize this behavior by customizing your logging configuration.
Django can also be configured to email errors about broken links (404 “page not found” errors). Django sends emails about 404 errors when:
If those conditions are met, Django will email the users listed in the
MANAGERS setting whenever your code raises a 404 and the request has
a referer. It doesn’t bother to email for 404s that don’t have a referer –
those are usually people typing in broken URLs or broken web bots. It also
ignores 404s when the referer is equal to the requested URL, since this
behavior is from broken web bots too.
You can tell Django to stop reporting particular 404s by tweaking the
IGNORABLE_404_URLS setting. It should be a list of compiled
regular expression objects. For example:
import re IGNORABLE_404_URLS = [ re.compile(r'\.(php|cgi)$'), re.compile(r'^/phpmyadmin/'), ]
In this example, a 404 to any URL ending with
.cgi will not be
reported. Neither will any URL starting with
The following example shows how to exclude some conventional URLs that browsers and crawlers often request:
import re IGNORABLE_404_URLS = [ re.compile(r'^/apple-touch-icon.*\.png$'), re.compile(r'^/favicon\.ico$'), re.compile(r'^/robots\.txt$'), ]
(Note that these are regular expressions, so we put a backslash in front of periods to escape them.)
If you’d like to customize the behavior of
django.middleware.common.BrokenLinkEmailsMiddleware further (for
example to ignore requests coming from web crawlers), you should subclass it
and override its methods.
404 errors are logged using the logging framework. By default, these log records are ignored, but you can use them for error reporting by writing a handler and configuring logging appropriately.
Filtering error reports¶
Filtering sensitive data is a hard problem, and it’s nearly impossible to guarantee that sensitive data won’t leak into an error report. Therefore, error reports should only be available to trusted team members and you should avoid transmitting error reports unencrypted over the internet (such as through email).
Filtering sensitive information¶
Error reports are really helpful for debugging errors, so it is generally
useful to record as much relevant information about those errors as possible.
For example, by default Django records the full traceback for the
exception raised, each traceback frame’s local variables, and the
However, sometimes certain types of information may be too sensitive and thus
may not be appropriate to be kept track of, for example a user’s password or
credit card number. So in addition to filtering out settings that appear to be
sensitive as described in the
DEBUG documentation, Django offers a
set of function decorators to help you control which information should be
filtered out of error reports in a production environment (that is, where
DEBUG is set to
If a function (either a view or any regular callback) in your code uses local variables susceptible to contain sensitive information, you may prevent the values of those variables from being included in error reports using the
from django.views.decorators.debug import sensitive_variables @sensitive_variables('user', 'pw', 'cc') def process_info(user): pw = user.pass_word cc = user.credit_card_number name = user.name ...
In the above example, the values for the
ccvariables will be hidden and replaced with stars (
**********) in the error reports, whereas the value of the
namevariable will be disclosed.
To systematically hide all local variables of a function from error logs, do not provide any argument to the
@sensitive_variables() def my_function(): ...
When using multiple decorators
If the variable you want to hide is also a function argument (e.g. ‘
user’ in the following example), and if the decorated function has multiple decorators, then make sure to place
@sensitive_variablesat the top of the decorator chain. This way it will also hide the function argument as it gets passed through the other decorators:
@sensitive_variables('user', 'pw', 'cc') @some_decorator @another_decorator def process_info(user): ...
If one of your views receives an
POST parameterssusceptible to contain sensitive information, you may prevent the values of those parameters from being included in the error reports using the
from django.views.decorators.debug import sensitive_post_parameters @sensitive_post_parameters('pass_word', 'credit_card_number') def record_user_profile(request): UserProfile.create( user=request.user, password=request.POST['pass_word'], credit_card=request.POST['credit_card_number'], name=request.POST['name'], ) ...
In the above example, the values for the
credit_card_numberPOST parameters will be hidden and replaced with stars (
**********) in the request’s representation inside the error reports, whereas the value of the
nameparameter will be disclosed.
To systematically hide all POST parameters of a request in error reports, do not provide any argument to the
@sensitive_post_parameters() def my_view(request): ...
All POST parameters are systematically filtered out of error reports for certain
authadmin) to prevent the leaking of sensitive information such as user passwords.
Custom error reports¶
sensitive_post_parameters() do is,
respectively, annotate the decorated function with the names of sensitive
variables and annotate the
HttpRequest object with the names of sensitive
POST parameters, so that this sensitive information can later be filtered out
of reports when an error occurs. The actual filtering is done by Django’s
default error reporter filter:
django.views.debug.SafeExceptionReporterFilter. This filter uses the
decorators’ annotations to replace the corresponding values with stars
**********) when the error reports are produced. If you wish to
override or customize this default behavior for your entire site, you need to
define your own filter class and tell Django to use it via the
DEFAULT_EXCEPTION_REPORTER_FILTER = 'path.to.your.CustomExceptionReporterFilter'
You may also control in a more granular way which filter to use within any
given view by setting the
def my_view(request): if request.user.is_authenticated: request.exception_reporter_filter = CustomExceptionReporterFilter() ...
Your custom filter class needs to inherit from
django.views.debug.SafeExceptionReporterFilter and may override the
following attributes and methods:
The string value to replace sensitive value with. By default it replaces the values of sensitive variables with stars (
A compiled regular expression object used to match settings and
request.METAvalues considered as sensitive. By default equivalent to:
import re re.compile(r'API|TOKEN|KEY|SECRET|PASS|SIGNATURE', flags=re.IGNORECASE)
Trueto activate the filtering in
get_traceback_frame_variables(). By default the filter is active if
False. Note that sensitive
request.METAvalues are always filtered along with sensitive setting values, as described in the
Returns the filtered dictionary of POST parameters. Sensitive values are replaced with
If you need to customize error reports beyond filtering you may specify a
custom error reporter class by defining the
DEFAULT_EXCEPTION_REPORTER = 'path.to.your.CustomExceptionReporter'
The exception reporter is responsible for compiling the exception report data,
and formatting it as text or HTML appropriately. (The exception reporter uses
DEFAULT_EXCEPTION_REPORTER_FILTER when preparing the exception
Your custom reporter class needs to inherit from
Property that returns a
pathlib.Pathrepresenting the absolute filesystem path to a template for rendering the HTML representation of the exception. Defaults to the Django provided template.
Property that returns a
pathlib.Pathrepresenting the absolute filesystem path to a template for rendering the plain-text representation of the exception. Defaults to the Django provided template.
Return a dictionary containing traceback information.
This is the main extension point for customizing exception reports, for example:
from django.views.debug import ExceptionReporter class CustomExceptionReporter(ExceptionReporter): def get_traceback_data(self): data = super().get_traceback_data() # ... remove/add something here ... return data
Return HTML version of exception report.
Used for HTML version of debug 500 HTTP error page.
Return plain text version of exception report.
Used for plain text version of debug 500 HTTP error page and email reports.
As with the filter class, you may control which exception reporter class to use
within any given view by setting the
def my_view(request): if request.user.is_authenticated: request.exception_reporter_class = CustomExceptionReporter() ...