Exposed JSON endpoint for Waffle flag/switch/sample state (#452)

Adds a JSON endpoint that returns the state of all flags/switches/samples.

In addition to the state, the endpoint also includes the last-modified time, which can be useful to identify stale flags that may need to be cleaned up.

docs/usage/index.rst

@@ -17,4 +17,5 @@ JavaScript.
    mixins
    templates
    javascript
+   json
    cli

docs/usage/json.rst

@@ -0,0 +1,62 @@
+.. _usage-json:
+
+=====================
+Waffle Status as JSON
+=====================
+
+Although :doc:`WaffleJS<javascript>` returns the status of all
+:ref:`flags <types-flag>`, :ref:`switches <types-switch>`, and
+:ref:`samples <types-sample>`, it does so by exposing a Javascript
+object, rather than returning the data in a directly consumable format.
+
+In cases where a directly consumable format is preferrable,
+Waffle also exposes this data as JSON via the ``waffle_status`` view.
+
+
+Using the view
+--------------
+
+Using the ``waffle_status`` view requires adding Waffle to your URL
+configuration. For example, in your ``ROOT_URLCONF``::
+
+    urlpatterns = patterns('',
+        (r'^', include('waffle.urls')),
+    )
+
+This adds a route called ``waffle_status``, which will return the current
+status of each flag, switch, and sample as JSON, with the following structure:
+
+.. code-block:: json
+
+    {
+        "flags": {
+            "flag_active": {
+                "is_active": true,
+                "last_modified": "2020-01-01T12:00:00.000"
+            },
+            "flag_inactive": {
+                "is_active": false,
+                "last_modified": "2020-01-01T12:00:00.000"
+            }
+        },
+        "switches": {
+            "switch_active": {
+                "is_active": true,
+                "last_modified": "2020-01-01T12:00:00.000"
+            },
+            "switch_inactive": {
+                "is_active": false,
+                "last_modified": "2020-01-01T12:00:00.000"
+            }
+        },
+        "samples": {
+            "sample_active": {
+                "is_active": true,
+                "last_modified": "2020-01-01T12:00:00.000"
+            },
+            "sample_inactive": {
+                "is_active": false,
+                "last_modified": "2020-01-01T12:00:00.000"
+            }
+        }
+    }

waffle/__init__.py

@@ -12,24 +12,32 @@
 
 
 def flag_is_active(request, flag_name, read_only=False):
-    flag = get_waffle_model('FLAG_MODEL').get(flag_name)
+    flag = get_waffle_flag_model().get(flag_name)
     return flag.is_active(request, read_only=read_only)
 
 
 def switch_is_active(switch_name):
-    switch = get_waffle_model('SWITCH_MODEL').get(switch_name)
+    switch = get_waffle_switch_model().get(switch_name)
     return switch.is_active()
 
 
 def sample_is_active(sample_name):
-    sample = get_waffle_model('SAMPLE_MODEL').get(sample_name)
+    sample = get_waffle_sample_model().get(sample_name)
     return sample.is_active()
 
 
 def get_waffle_flag_model():
     return get_waffle_model('FLAG_MODEL')
 
 
+def get_waffle_switch_model():
+    return get_waffle_model('SWITCH_MODEL')
+
+
+def get_waffle_sample_model():
+    return get_waffle_model('SAMPLE_MODEL')
+
+
 def get_waffle_model(setting_name):
     """
     Returns the waffle Flag model that is active in this project.

waffle/tests/test_views.py

@@ -1,6 +1,6 @@
 from django.urls import reverse
 
-from waffle import get_waffle_flag_model
+from waffle import get_waffle_flag_model, get_waffle_sample_model, get_waffle_switch_model
 from waffle.models import Sample, Switch
 from waffle.tests.base import TestCase
 
@@ -14,6 +14,41 @@ def test_wafflejs(self):
                          for control in response['cache-control'].split(',')]
         self.assertIn('max-age=0', cache_control)
 
+    def test_waffle_status(self):
+        response = self.client.get(reverse('waffle_status'))
+        self.assertEqual(200, response.status_code)
+        self.assertEqual('application/json', response['content-type'])
+        cache_control = [control.strip()
+                         for control in response['cache-control'].split(',')]
+        self.assertIn('max-age=0', cache_control)
+
+    def test_waffle_status_response(self):
+        get_waffle_flag_model().objects.create(name='test_flag_active', everyone=True)
+        get_waffle_flag_model().objects.create(name='test_flag_inactive', everyone=False)
+        get_waffle_switch_model().objects.create(name='test_switch_active', active=True)
+        get_waffle_switch_model().objects.create(name='test_switch_inactive', active=False)
+        get_waffle_sample_model().objects.create(name='test_sample_active', percent=100)
+        get_waffle_sample_model().objects.create(name='test_sample_inactive', percent=0)
+
+        response = self.client.get(reverse('waffle_status'))
+        self.assertEqual(200, response.status_code)
+        content = response.json()
+
+        assert 'test_flag_active' in content['flags'].keys()
+        assert content['flags']['test_flag_active']['is_active']
+        assert 'test_flag_inactive' in content['flags'].keys()
+        assert not content['flags']['test_flag_inactive']['is_active']
+
+        assert 'test_switch_active' in content['switches'].keys()
+        assert content['switches']['test_switch_active']['is_active']
+        assert 'test_switch_inactive' in content['switches'].keys()
+        assert not content['switches']['test_switch_inactive']['is_active']
+
+        assert 'test_sample_active' in content['samples'].keys()
+        assert content['samples']['test_sample_active']['is_active']
+        assert 'test_sample_inactive' in content['samples'].keys()
+        assert not content['samples']['test_sample_inactive']['is_active']
+
     def test_flush_all_flags(self):
         """Test the 'FLAGS_ALL' list gets invalidated correctly."""
         get_waffle_flag_model().objects.create(name='myflag1', everyone=True)

waffle/urls.py

@@ -1,7 +1,8 @@
 from django.urls import path
 
-from waffle.views import wafflejs
+from waffle.views import wafflejs, waffle_json
 
 urlpatterns = [
     path('wafflejs', wafflejs, name='wafflejs'),
+    path('waffle_status', waffle_json, name='waffle_status'),
 ]

waffle/views.py

@@ -1,9 +1,8 @@
-from django.http import HttpResponse
+from django.http import HttpResponse, JsonResponse
 from django.template import loader
 from django.views.decorators.cache import never_cache
 
-from waffle import get_waffle_flag_model
-from waffle.models import Sample, Switch
+from waffle import get_waffle_flag_model, get_waffle_switch_model, get_waffle_sample_model
 from waffle.utils import get_setting
 
 
@@ -17,10 +16,10 @@ def _generate_waffle_js(request):
     flags = get_waffle_flag_model().get_all()
     flag_values = [(f.name, f.is_active(request)) for f in flags]
 
-    switches = Switch.get_all()
+    switches = get_waffle_switch_model().get_all()
     switch_values = [(s.name, s.is_active()) for s in switches]
 
-    samples = Sample.get_all()
+    samples = get_waffle_sample_model().get_all()
     sample_values = [(s.name, s.is_active()) for s in samples]
 
     return loader.render_to_string('waffle/waffle.js', {
@@ -31,3 +30,43 @@ def _generate_waffle_js(request):
         'switch_default': get_setting('SWITCH_DEFAULT'),
         'sample_default': get_setting('SAMPLE_DEFAULT'),
     })
+
+
+@never_cache
+def waffle_json(request):
+    return JsonResponse(_generate_waffle_json(request))
+
+
+def _generate_waffle_json(request):
+    flags = get_waffle_flag_model().get_all()
+    flag_values = {
+        f.name: {
+            'is_active': f.is_active(request),
+            'last_modified': f.modified,
+        }
+        for f in flags
+    }
+
+    switches = get_waffle_switch_model().get_all()
+    switch_values = {
+        s.name: {
+            'is_active': s.is_active(),
+            'last_modified': s.modified,
+        }
+        for s in switches
+    }
+
+    samples = get_waffle_sample_model().get_all()
+    sample_values = {
+        s.name: {
+            'is_active': s.is_active(),
+            'last_modified': s.modified,
+        }
+        for s in samples
+    }
+
+    return {
+        'flags': flag_values,
+        'switches': switch_values,
+        'samples': sample_values,
+    }