A debug/profiling overlay for Django

Last update: Oct 17, 2022

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Overview

Django Debug Toolbar

The Django Debug Toolbar is a configurable set of panels that display various debug information about the current request/response and when clicked, display more details about the panel's content.

Currently, the following panels have been written and are working:

Django version
Request timer
A list of settings in settings.py
Common HTTP headers
GET/POST/cookie/session variable display
Templates and context used, and their template paths
SQL queries including time to execute and links to EXPLAIN each query
List of signals, their args and receivers
Logging output via Python's built-in logging, or via the logbook module

There is also one Django management command currently:

debugsqlshell: Outputs the SQL that gets executed as you work in the Python interactive shell. (See example below)

If you have ideas for other panels please let us know.

Installation

Add the debug_toolbar directory to your Python path.
Add the following middleware to your project's settings.py file:

'debug_toolbar.middleware.DebugToolbarMiddleware',

Tying into middleware allows each panel to be instantiated on request and rendering to happen on response.

The order of MIDDLEWARE_CLASSES is important: the Debug Toolbar middleware must come after any other middleware that encodes the response's content (such as GZipMiddleware).

Note: The debug toolbar will only display itself if the mimetype of the response is either text/html or application/xhtml+xml and contains a closing </body> tag.

Note: Be aware of middleware ordering and other middleware that may intercept requests and return responses. Putting the debug toolbar middleware after the Flatpage middleware, for example, means the toolbar will not show up on flatpages.
Make sure your IP is listed in the INTERNAL_IPS setting. If you are working locally this will be:

INTERNAL_IPS = ('127.0.0.1',)

Note: This is required because of the built-in requirements of the show_toolbar method. See below for how to define a method to determine your own logic for displaying the toolbar.
Add debug_toolbar to your INSTALLED_APPS setting so Django can find the template files associated with the Debug Toolbar.

Alternatively, add the path to the debug toolbar templates ('path/to/debug_toolbar/templates' to your TEMPLATE_DIRS setting.)

Configuration

The debug toolbar has two settings that can be set in settings.py:

Optional: Add a tuple called DEBUG_TOOLBAR_PANELS to your settings.py file that specifies the full Python path to the panel that you want included in the Toolbar. This setting looks very much like the MIDDLEWARE_CLASSES setting. For example:

DEBUG_TOOLBAR_PANELS = (
    'debug_toolbar.panels.version.VersionDebugPanel',
    'debug_toolbar.panels.timer.TimerDebugPanel',
    'debug_toolbar.panels.settings_vars.SettingsVarsDebugPanel',
    'debug_toolbar.panels.headers.HeaderDebugPanel',
    'debug_toolbar.panels.request_vars.RequestVarsDebugPanel',
    'debug_toolbar.panels.template.TemplateDebugPanel',
    'debug_toolbar.panels.sql.SQLDebugPanel',
    'debug_toolbar.panels.signals.SignalDebugPanel',
    'debug_toolbar.panels.logger.LoggingPanel',
)

You can change the ordering of this tuple to customize the order of the panels you want to display, or add/remove panels. If you have custom panels you can include them in this way -- just provide the full Python path to your panel.

Optional: There are a few configuration options to the debug toolbar that can be placed in a dictionary:
- INTERCEPT_REDIRECTS: If set to True (default), the debug toolbar will show an intermediate page upon redirect so you can view any debug information prior to redirecting. This page will provide a link to the redirect destination you can follow when ready. If set to False, redirects will proceed as normal.
- SHOW_TOOLBAR_CALLBACK: If not set or set to None, the debug_toolbar middleware will use its built-in show_toolbar method for determining whether the toolbar should show or not. The default checks are that DEBUG must be set to True and the IP of the request must be in INTERNAL_IPS. You can provide your own method for displaying the toolbar which contains your custom logic. This method should return True or False.
- EXTRA_SIGNALS: An array of custom signals that might be in your project, defined as the python path to the signal.
- HIDE_DJANGO_SQL: If set to True (the default) then code in Django itself won't be shown in SQL stacktraces.
- SHOW_TEMPLATE_CONTEXT: If set to True (the default) then a template's context will be included with it in the Template debug panel. Turning this off is useful when you have large template contexts, or you have template contexts with lazy datastructures that you don't want to be evaluated.
- TAG: If set, this will be the tag to which debug_toolbar will attach the debug toolbar. Defaults to 'body'.
Example configuration:
```
def custom_show_toolbar(request):
    return True # Always show toolbar, for example purposes only.

DEBUG_TOOLBAR_CONFIG = {
    'INTERCEPT_REDIRECTS': False,
    'SHOW_TOOLBAR_CALLBACK': custom_show_toolbar,
    'EXTRA_SIGNALS': ['myproject.signals.MySignal'],
    'HIDE_DJANGO_SQL': False,
    'TAG': 'div',
}
```

debugsqlshell

The following is sample output from running the debugsqlshell management command. Each ORM call that results in a database query will be beautifully output in the shell:

$ ./manage.py debugsqlshell
Python 2.6.1 (r261:67515, Jul  7 2009, 23:51:51)
[GCC 4.2.1 (Apple Inc. build 5646)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from page.models import Page
>>> ### Lookup and use resulting in an extra query...
>>> p = Page.objects.get(pk=1)
SELECT "page_page"."id",
       "page_page"."number",
       "page_page"."template_id",
       "page_page"."description"
FROM "page_page"
WHERE "page_page"."id" = 1

>>> print p.template.name
SELECT "page_template"."id",
       "page_template"."name",
       "page_template"."description"
FROM "page_template"
WHERE "page_template"."id" = 1

Home
>>> ### Using select_related to avoid 2nd database call...
>>> p = Page.objects.select_related('template').get(pk=1)
SELECT "page_page"."id",
       "page_page"."number",
       "page_page"."template_id",
       "page_page"."description",
       "page_template"."id",
       "page_template"."name",
       "page_template"."description"
FROM "page_page"
INNER JOIN "page_template" ON ("page_page"."template_id" = "page_template"."id")
WHERE "page_page"."id" = 1

>>> print p.template.name
Home

TODOs and BUGS

See: https://github.com/django-debug-toolbar/django-debug-toolbar/issues

Comments

multiple jquery installations

I was having lots of issues with jQuery and I just realized that it was because debug-toolbar is adding their own version of the library.

It was somehow resetting my plugins when your jQuery library was pulled. I see that you are running it in no conflict, but unfortunately that is doing me no good. I was able to comment out the inclusion of your library (v 1.2.6) and just let debug-toolbar use mine (v 1.3.2) and everything worked fine.

It would be nice if debug-toolbar could recognize if jQuery was already installed and then just skip it's own installation.

opened by aroscoe 5
Using raw sql (cursors) with executemany breaks debug toolbar

Relevant traceback:

File 'E:\Projects\farmforce\farmforce\fftenant\tags.py', line 77 in add_multiple_tags cursor.executemany(query, params) File 'C:\Python27\lib\site-packages\django_debug_toolbar-0.8.5-py2.7.egg\debug_toolbar\panels\sql.py', line 199 in executemany 'sql': self.db.ops.last_executed_query(self.cursor, sql, params), File 'C:\Python27\lib\site-packages\django\db\backends*init*.py', line 505 in last_executed_query return smart_unicode(sql) % u_params TypeError: not all arguments converted during string formatting

opened by eloff 3
Profiling and debugging a production site

Currently, the way DDT works is by configuring the deployment in DEBUG mode (DEBUG = True), and by specifying the IP addresses of those that should have access. This all works quite nicely in a development environment, but it makes it extremely difficult to profile a live site.

Has there been discussion of possible alternative methods for enabling the toolbar on a live site? Perhaps by using permissions, or simply the user.is_admin()? If developers are always able to access debug information, chances are higher that performance will be monitored via developers dogfooding their own sites.

I'd be quite interested in developing a different method for enabling the toolbar. I'm just wondering if I'm covering old ground, and if there are significant reasons that things work the way they do?

opened by jarshwah 2
SQL panel makes error in Django 1.3

In Django 1.3, debug_toolbar.panels.sql.SQLDebugPanel makes an error: TemplateSyntaxError at / Caught AttributeError while rendering: 'Cursor' object has no attribute 'db'

opened by ghost 1
rev 15493 breaks debug_toolbar

filling a new ticket as I accidentally closed the last one and can't open it again. CursorWrapper.db was renamed to CursorWrapper.connection , this should be fixed before 1.3 lands..

https://github.com/robhudson/django-debug-toolbar/blob/master/debug_toolbar/panels/sql.py#L117

Filled under issue 139 in rob's fork

opened by rasca 1
settings.MEDIA_URL could be None

Hi,

Here is a quick bug fix. settings.MEDIA_URL is used when deciding if the toolbar should be visible or not. But in my setup settings.MEDIA_URL is None (I use django-static for static files) so the toolbar crashes.

///Kalle

opened by kalle 1
Profiling panel: Caught ValueError while rendering: need more than 1 value to unpack

Same as Issue #16, but for profiling panel.

On Windows, splitting a path with '/' does not work well ;-)

The exception is located at debug_toolbar/panels/profiling.py in content, line 65 Bug fixed by importing os, and replacing '/' by os.path.sep

opened by olexiystrashko 0

Django gives errors when DjDT tries to render itself on JSON responses.

Perhaps DjDT needs to check the response MIME type and only insert itself on JSON responses. We're using a RestView class (http://djangosnippets.org/snippets/1071/) with the django-annoying @ajax_request decorator and DjDT tries to attach itself to the response, failing.

The traceback:

Traceback (most recent call last):
  File "/var/myproject/env/lib/python2.6/site-packages/django/contrib/staticfiles/handlers.py", line 68, in __call__
    return self.application(environ, start_response)
  File "/var/myproject/env/lib/python2.6/site-packages/django/core/handlers/wsgi.py", line 273, in __call__
    response = self.get_response(request)
  File "/var/myproject/env/lib/python2.6/site-packages/django/core/handlers/base.py", line 182, in get_response
    response = self.handle_uncaught_exception(request, resolver, sys.exc_info())
  File "/var/myproject/env/lib/python2.6/site-packages/django/core/handlers/base.py", line 203, in handle_uncaught_exception
    return debug.technical_500_response(request, *exc_info)
  File "/var/myproject/env/lib/python2.6/site-packages/django/core/handlers/base.py", line 178, in get_response
    response = middleware_method(request, response)
  File "/var/myproject/env/lib/python2.6/site-packages/debug_toolbar/middleware.py", line 106, in process_response
    smart_unicode(self.debug_toolbars[request].render_toolbar() + self.tag))
  File "/var/myproject/env/lib/python2.6/site-packages/debug_toolbar/toolbar/loader.py", line 78, in render_toolbar
    return render_to_string('debug_toolbar/base.html', context)
  File "/var/myproject/env/lib/python2.6/site-packages/django/template/loader.py", line 183, in render_to_string
    return t.render(Context(dictionary))
  File "/var/myproject/env/lib/python2.6/site-packages/django/template/base.py", line 123, in render
    return self._render(context)
  File "/var/myproject/env/lib/python2.6/site-packages/django/test/utils.py", line 57, in instrumented_test_render
    return self.nodelist.render(context)
  File "/var/myproject/env/lib/python2.6/site-packages/django/template/base.py", line 744, in render
    bits.append(self.render_node(node, context))
  File "/var/myproject/env/lib/python2.6/site-packages/django/template/debug.py", line 73, in render_node
    result = node.render(context)
  File "/var/myproject/env/lib/python2.6/site-packages/django/template/defaulttags.py", line 227, in render
    nodelist.append(node.render(context))
  File "/var/myproject/env/lib/python2.6/site-packages/django/template/defaulttags.py", line 311, in render
    return self.nodelist_true.render(context)
  File "/var/myproject/env/lib/python2.6/site-packages/django/template/base.py", line 744, in render
    bits.append(self.render_node(node, context))
  File "/var/myproject/env/lib/python2.6/site-packages/django/template/debug.py", line 73, in render_node
    result = node.render(context)
  File "/var/myproject/env/lib/python2.6/site-packages/django/template/debug.py", line 90, in render
    output = self.filter_expression.resolve(context)
  File "/var/myproject/env/lib/python2.6/site-packages/django/template/base.py", line 510, in resolve
    obj = self.var.resolve(context)
  File "/var/myproject/env/lib/python2.6/site-packages/django/template/base.py", line 653, in resolve
    value = self._resolve_lookup(context)
  File "/var/myproject/env/lib/python2.6/site-packages/django/template/base.py", line 698, in _resolve_lookup
    current = current()
  File "/var/myproject/env/lib/python2.6/site-packages/debug_toolbar/panels/request_vars.py", line 35, in content
    'view_func': '%s.%s' % (self.view_func.__module__, self.view_func.__name__),
TemplateSyntaxError: Caught AttributeError while rendering: 'RestView' object has no attribute '__name__'

opened by skorokithakis 1

Caught IndexError while rendering: tuple index out of range

On Windows, splitting a path with '/' does not work well ;-)

The exception is located at debug_toolbar/panels/sql.py in content, line 195 Bug fixed by importing os, and replacing '/' by os.path.sep

opened by tlesne 4

A debug/profiling overlay for Django

Related tags

Overview

Django Debug Toolbar

Installation

Configuration

debugsqlshell

TODOs and BUGS

Comments

multiple jquery installations

Using raw sql (cursors) with executemany breaks debug toolbar

Profiling and debugging a production site

SQL panel makes error in Django 1.3

rev 15493 breaks debug_toolbar

settings.MEDIA_URL could be None

Profiling panel: Caught ValueError while rendering: need more than 1 value to unpack

Django gives errors when DjDT tries to render itself on JSON responses.

Caught IndexError while rendering: tuple index out of range

Owner

David Cramer

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