Add tip on how to display the Django Debug Toolbar to the docs

apps/amo/tests/test_middleware.py

@@ -109,3 +109,13 @@ class TestNoAddonsMiddleware(amo.tests.TestCase):
         self.assertRaises(http.Http404, self.process, 'some.addons')
         self.assertRaises(http.Http404, self.process, 'some.addons.thingy')
         assert not self.process('something.else')
+
+
+class TestNoDjangoDebugToolbar(amo.tests.TestCase):
+    """Make sure the Django Debug Toolbar isn't available when DEBUG=False."""
+
+    def test_no_django_debug_toolbar(self):
+        with self.settings(DEBUG=False):
+            res = self.client.get(reverse('home'), follow=True)
+            assert 'djDebug' not in res.content
+            assert 'debug_toolbar' not in res.content

docs/topics/hacking/debugging.rst

@@ -46,5 +46,25 @@ All being well it should look like this:
 .. image:: /screenshots/docker-ipdb.png
 
 
+Using the Django Debug Toolbar
+------------------------------
+
+The `Django Debug Toolbar`_ is very powerful and useful when viewing pages from
+the website, to check the view used, its parameters, the SQL queries, the
+templates rendered and their context...
+
+It should be enabled local development as long as ``settings.DEBUG`` is set to
+``True`` (which it is by default).
+
+All being well it should look like this at the top-right of any web page on
+olympia:
+
+.. image:: /screenshots/django-debug-toolbar.png
+
+If clicked, it looks like:
+
+.. image:: /screenshots/django-debug-toolbar-expanded.png
+
 .. _ipdb: https://pypi.python.org/pypi/ipdb
 .. _docker-utils: https://pypi.python.org/pypi/docker-utils
+.. _Django Debug Toolbar: http://django-debug-toolbar.readthedocs.org/en/1.3.2/index.html

requirements/dev.txt

@@ -2,6 +2,6 @@
 -r docs.txt
 -r flake8.txt
 
-django-debug-toolbar==1.2
+django-debug-toolbar==1.3.2
 django-fixture-magic==0.0.4
 sqlparse==0.1.14

settings.py

@@ -79,6 +79,27 @@ TASK_USER_ID = 10968
 # Set to True if we're allowed to use X-SENDFILE.
 XSENDFILE = False
 
+# Enable the Django Debug Toolbar for local dev.
+INSTALLED_APPS += (
+    'debug_toolbar',
+)
+DEBUG_TOOLBAR_PATCH_SETTINGS = False  # Prevent DDT from patching the settings.
+
+MIDDLEWARE_CLASSES += ('debug_toolbar.middleware.DebugToolbarMiddleware',)
+
+
+def show_toolbar_callback(request):
+    """Callback used by the Django Debug Toolbar to decide when to display."""
+    # We want to make sure to have the DEBUG value at runtime, not the one we
+    # have in this specific settings file.
+    from django.conf import settings
+    return settings.DEBUG
+
+
+DEBUG_TOOLBAR_CONFIG = {
+    "SHOW_TOOLBAR_CALLBACK": "settings.show_toolbar_callback",
+}
+
 # If you have settings you want to overload, put them in a local_settings.py.
 try:
     from local_settings import *  # noqa