feat(core): add robust health check endpoint with modular service checks

core/tests/test_health_check.py

@@ -0,0 +1,132 @@
+from django.test import TestCase
+from rest_framework.test import APITestCase
+from rest_framework import status
+from unittest.mock import patch, MagicMock
+from django.conf import settings
+import os
+
+from core.views import HealthCheckView
+
+
+class HealthCheckViewTest(APITestCase):
+    def setUp(self):
+        self.url = '/core/health/'
+        # Ensure no OpenAI key for some tests
+        if 'OPENAI_API_KEY' in os.environ:
+            del os.environ['OPENAI_API_KEY']
+
+    @patch('core.views.connection.cursor')
+    @patch('core.views.Redis.from_url')
+    @patch('core.views.OpenAI')
+    def test_health_check_all_healthy(self, mock_openai, mock_redis, mock_cursor):
+        # Mock DB success
+        mock_cursor_instance = MagicMock()
+        mock_cursor.return_value.__enter__.return_value = mock_cursor_instance
+        mock_cursor_instance.execute.return_value = None
+
+        # Mock Redis success
+        mock_redis_instance = MagicMock()
+        mock_redis_instance.ping.return_value = True
+        mock_redis.return_value = mock_redis_instance
+
+        # Mock OpenAI success (key set)
+        os.environ['OPENAI_API_KEY'] = 'test-key'
+        mock_client = MagicMock()
+        mock_client.models.list.return_value = MagicMock()
+        mock_openai.return_value = mock_client
+
+        response = self.client.get(self.url)
+
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        data = response.json()
+        self.assertEqual(data['overall'], 'healthy')
+        self.assertEqual(data['services']['db'], 'healthy')
+        self.assertEqual(data['services']['redis'], 'healthy')
+        self.assertEqual(data['services']['openai'], 'healthy')
+
+    @patch('core.views.connection.cursor')
+    @patch('core.views.Redis.from_url')
+    def test_health_check_openai_skipped(self, mock_redis, mock_cursor):
+        # Mock DB and Redis success
+        mock_cursor_instance = MagicMock()
+        mock_cursor.return_value.__enter__.return_value = mock_cursor_instance
+        mock_cursor_instance.execute.return_value = None
+
+        mock_redis_instance = MagicMock()
+        mock_redis_instance.ping.return_value = True
+        mock_redis.return_value = mock_redis_instance
+
+        # No OpenAI key
+        if 'OPENAI_API_KEY' in os.environ:
+            del os.environ['OPENAI_API_KEY']
+
+        response = self.client.get(self.url)
+
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        data = response.json()
+        self.assertEqual(data['overall'], 'healthy')
+        self.assertEqual(data['services']['db'], 'healthy')
+        self.assertEqual(data['services']['redis'], 'healthy')
+        self.assertEqual(data['services']['openai'], 'skipped')
+
+    @patch('core.views.connection.cursor')
+    @patch('core.views.Redis.from_url')
+    @patch('core.views.OpenAI')
+    def test_health_check_openai_unhealthy(self, mock_openai, mock_redis, mock_cursor):
+        # Mock DB and Redis success
+        mock_cursor_instance = MagicMock()
+        mock_cursor.return_value.__enter__.return_value = mock_cursor_instance
+        mock_cursor_instance.execute.return_value = None
+
+        mock_redis_instance = MagicMock()
+        mock_redis_instance.ping.return_value = True
+        mock_redis.return_value = mock_redis_instance
+
+        # Mock OpenAI failure
+        os.environ['OPENAI_API_KEY'] = 'test-key'
+        mock_openai.side_effect = Exception('API error')
+
+        response = self.client.get(self.url)
+
+        self.assertEqual(response.status_code, status.HTTP_200_OK)
+        data = response.json()
+        self.assertEqual(data['overall'], 'healthy')
+        self.assertEqual(data['services']['db'], 'healthy')
+        self.assertEqual(data['services']['redis'], 'healthy')
+        self.assertEqual(data['services']['openai'], 'unhealthy')
+
+    @patch('core.views.connection.cursor')
+    @patch('core.views.Redis.from_url')
+    def test_health_check_db_unhealthy(self, mock_redis, mock_cursor):
+        # Mock DB failure
+        mock_cursor.side_effect = Exception('DB error')
+
+        # Mock Redis success
+        mock_redis_instance = MagicMock()
+        mock_redis_instance.ping.return_value = True
+        mock_redis.return_value = mock_redis_instance
+
+        response = self.client.get(self.url)
+
+        self.assertEqual(response.status_code, status.HTTP_503_SERVICE_UNAVAILABLE)
+        data = response.json()
+        self.assertEqual(data['overall'], 'unhealthy')
+        self.assertEqual(data['services']['db'], 'unhealthy')
+
+    @patch('core.views.connection.cursor')
+    @patch('core.views.Redis.from_url')
+    def test_health_check_redis_unhealthy(self, mock_redis, mock_cursor):
+        # Mock DB success
+        mock_cursor_instance = MagicMock()
+        mock_cursor.return_value.__enter__.return_value = mock_cursor_instance
+        mock_cursor_instance.execute.return_value = None
+
+        # Mock Redis failure
+        mock_redis.side_effect = Exception('Redis error')
+
+        response = self.client.get(self.url)
+
+        self.assertEqual(response.status_code, status.HTTP_503_SERVICE_UNAVAILABLE)
+        data = response.json()
+        self.assertEqual(data['overall'], 'unhealthy')
+        self.assertEqual(data['services']['redis'], 'unhealthy')

core/urls.py

@@ -1,10 +1,11 @@
 from django.urls import path, include
 from rest_framework.routers import DefaultRouter
-from core.views import CreateCheckoutSessionView, StripeWebhookView, PlanListView, CreateBillingPortalSessionView, VerifyCheckoutSessionView
+from core.views import CreateCheckoutSessionView, StripeWebhookView, PlanListView, CreateBillingPortalSessionView, VerifyCheckoutSessionView, HealthCheckView
 
 router = DefaultRouter()
 
 urlpatterns = [
+    path('health/', HealthCheckView.as_view(), name='health_check'),
     path('payments/create-checkout-session/', CreateCheckoutSessionView.as_view(), name='create_checkout_session'),
     path('payments/webhook/stripe/', StripeWebhookView.as_view(), name='stripe_webhook'),
     path('payments/verify-session/', VerifyCheckoutSessionView.as_view(), name='verify_checkout_session'),

core/views.py

@@ -17,6 +17,10 @@
 from django.core.cache import cache
 from dj_rest_auth.registration.views import SocialLoginView
 from allauth.socialaccount.providers.google.views import GoogleOAuth2Adapter
+from django.db import connection
+from redis import Redis
+from openai import OpenAI
+import os
 
 import stripe
 import logging
@@ -377,4 +381,109 @@ def get(self, request):
 
         except Exception as e:
             logger.error(f"❌ Error verifying Stripe session {session_id}: {e}")
-            return Response({"error": str(e)}, status=status.HTTP_500_INTERNAL_SERVER_ERROR)
+            return Response({"error": str(e)}, status=status.HTTP_500_INTERNAL_SERVER_ERROR)
+
+
+@extend_schema(
+    responses={
+        200: {
+            'type': 'object',
+            'properties': {
+                'overall': {'type': 'string'},
+                'services': {
+                    'type': 'object',
+                    'properties': {
+                        'db': {'type': 'string'},
+                        'redis': {'type': 'string'},
+                        'openai': {'type': 'string'},
+                    }
+                }
+            }
+        },
+        503: {
+            'type': 'object',
+            'properties': {
+                'overall': {'type': 'string'},
+                'services': {
+                    'type': 'object',
+                    'properties': {
+                        'db': {'type': 'string'},
+                        'redis': {'type': 'string'},
+                        'openai': {'type': 'string'},
+                    }
+                }
+            }
+        },
+    },
+    examples=[
+        OpenApiExample(
+            name="Healthy services",
+            value={
+                "overall": "healthy",
+                "services": {
+                    "db": "healthy",
+                    "redis": "healthy",
+                    "openai": "healthy"
+                }
+            },
+            response_only=True
+        ),
+        OpenApiExample(
+            name="OpenAI skipped",
+            value={
+                "overall": "healthy",
+                "services": {
+                    "db": "healthy",
+                    "redis": "healthy",
+                    "openai": "skipped"
+                }
+            },
+            response_only=True
+        )
+    ]
+)
+class HealthCheckView(APIView):
+    permission_classes = [AllowAny]
+
+    def get(self, request):
+        services = {}
+
+        # Check DB
+        try:
+            with connection.cursor() as cursor:
+                cursor.execute("SELECT 1")
+            services['db'] = 'healthy'
+        except Exception as e:
+            logger.error(f"DB health check failed: {e}")
+            services['db'] = 'unhealthy'
+
+        # Check Redis
+        try:
+            redis_client = Redis.from_url(settings.CACHE_URL)
+            redis_client.ping()
+            services['redis'] = 'healthy'
+        except Exception as e:
+            logger.error(f"Redis health check failed: {e}")
+            services['redis'] = 'unhealthy'
+
+        # Check OpenAI (optional)
+        api_key = os.getenv("OPENAI_API_KEY")
+        if api_key:
+            try:
+                client = OpenAI(api_key=api_key)
+                client.models.list()  # Lightweight check
+                services['openai'] = 'healthy'
+            except Exception as e:
+                logger.error(f"OpenAI health check failed: {e}")
+                services['openai'] = 'unhealthy'
+        else:
+            services['openai'] = 'skipped'
+
+        # Determine overall status
+        overall = 'healthy' if services['db'] == 'healthy' and services['redis'] == 'healthy' else 'unhealthy'
+        http_status = status.HTTP_200_OK if overall == 'healthy' else status.HTTP_503_SERVICE_UNAVAILABLE
+
+        return Response({
+            'overall': overall,
+            'services': services
+        }, status=http_status)