From da99b8b034a0566548cf9691df8e09a6efe1689b Mon Sep 17 00:00:00 2001
From: McKenna Jones <mckenna.jones@mediakind.com>
Date: Fri, 20 Jan 2023 14:26:58 -0700
Subject: [PATCH] Add Health Check endpoint  (#392)
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* add simple health endpoint

* add curl and healthcheck to dockerfile

* convert to view

* add simple test

* Add unhealthy test

* Cleanup

* check for LD_SERVER_PORT env var in healthcheck def

* Revert changes to middlewares.py

Co-authored-by: Sascha Ißbrücker <sascha.issbruecker@gmail.com>
---
 Dockerfile                          |  6 ++++-
 bookmarks/tests/test_health_view.py | 36 +++++++++++++++++++++++++++++
 bookmarks/urls.py                   |  2 ++
 bookmarks/views/__init__.py         |  1 +
 bookmarks/views/health.py           | 20 ++++++++++++++++
 5 files changed, 64 insertions(+), 1 deletion(-)
 create mode 100644 bookmarks/tests/test_health_view.py
 create mode 100644 bookmarks/views/health.py

diff --git a/Dockerfile b/Dockerfile
index e99dd27..74e1c30 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -34,7 +34,7 @@ RUN mkdir /opt/venv && \
 
 
 FROM python:3.10.6-slim-buster as final
-RUN apt-get update && apt-get -y install mime-support libpq-dev
+RUN apt-get update && apt-get -y install mime-support libpq-dev curl
 WORKDIR /etc/linkding
 # copy prod dependencies
 COPY --from=prod-deps /opt/venv /opt/venv
@@ -51,4 +51,8 @@ ENV PATH /opt/venv/bin:$PATH
 RUN ["chmod", "g+w", "."]
 # Run bootstrap logic
 RUN ["chmod", "+x", "./bootstrap.sh"]
+
+HEALTHCHECK --interval=30s --retries=3 --timeout=1s \
+CMD curl -f http://localhost:${LD_SERVER_PORT:-9090}/health || exit 1
+
 CMD ["./bootstrap.sh"]
diff --git a/bookmarks/tests/test_health_view.py b/bookmarks/tests/test_health_view.py
new file mode 100644
index 0000000..a43f79d
--- /dev/null
+++ b/bookmarks/tests/test_health_view.py
@@ -0,0 +1,36 @@
+from unittest.mock import patch
+
+from django.db import connections
+from django.test import TestCase
+
+from bookmarks.views.settings import app_version
+
+
+class HealthViewTestCase(TestCase):
+
+    def test_health_healthy(self):
+        response = self.client.get("/health")
+
+        self.assertEqual(response.status_code, 200)
+
+        response_body = response.json()
+        expected_body = {
+            'version': app_version,
+            'status': 'healthy'
+        }
+        self.assertDictEqual(response_body, expected_body)
+
+    def test_health_unhealhty(self):
+        with patch.object(connections['default'], 'ensure_connection') as mock_ensure_connection:
+            mock_ensure_connection.side_effect = Exception('Connection error')
+
+            response = self.client.get("/health")
+
+            self.assertEqual(response.status_code, 500)
+
+            response_body = response.json()
+            expected_body = {
+                'version': app_version,
+                'status': 'unhealthy'
+            }
+            self.assertDictEqual(response_body, expected_body)
diff --git a/bookmarks/urls.py b/bookmarks/urls.py
index cdb5016..1c2387d 100644
--- a/bookmarks/urls.py
+++ b/bookmarks/urls.py
@@ -31,4 +31,6 @@ urlpatterns = [
     # Feeds
     path('feeds/<str:feed_key>/all', AllBookmarksFeed(), name='feeds.all'),
     path('feeds/<str:feed_key>/unread', UnreadBookmarksFeed(), name='feeds.unread'),
+    # Health check
+    path('health', views.health, name='health')
 ]
diff --git a/bookmarks/views/__init__.py b/bookmarks/views/__init__.py
index 84f3f08..948a4ad 100644
--- a/bookmarks/views/__init__.py
+++ b/bookmarks/views/__init__.py
@@ -1,3 +1,4 @@
 from .bookmarks import *
 from .settings import *
 from .toasts import *
+from .health import health
diff --git a/bookmarks/views/health.py b/bookmarks/views/health.py
new file mode 100644
index 0000000..38923f1
--- /dev/null
+++ b/bookmarks/views/health.py
@@ -0,0 +1,20 @@
+from django.db import connections
+from django.http import JsonResponse
+
+from bookmarks.views.settings import app_version
+
+
+def health(request):
+    code = 200
+    response = {
+        'version': app_version,
+        'status': 'healthy'
+    }
+
+    try:
+        connections['default'].ensure_connection()
+    except Exception:
+        response['status'] = 'unhealthy'
+        code = 500
+
+    return JsonResponse(response, status=code)