added healthchecks to dockerfile

Author: zeylos

src/backend/Dockerfile

@@ -126,3 +126,6 @@ COPY . /app/
 
 # The default command runs gunicorn WSGI server in messages's main module
 CMD ["gunicorn", "-c", "/app/gunicorn.conf.py", "messages.wsgi:application"]
+
+HEALTHCHECK --interval=30s --timeout=2s --start-period=30s \
+  CMD ["python", "-c", "import os; from urllib.request import Request, urlopen; urlopen(Request('http://localhost:8000/healthz/', headers={'Host': f'{os.getenv('DJANGO_ALLOWED_HOSTS', 'localhost').split(',')[0].strip()}', 'X-Forwarded-Proto': 'https'}), timeout=2)"]

src/frontend/Dockerfile

@@ -32,3 +32,6 @@ COPY nginx/nginx.conf.template /etc/nginx/templates/default.conf.template
 ENV MESSAGES_FRONTEND_PORT=8080
 ENV MESSAGES_FRONTEND_BACKEND_SERVER=localhost:8000
 ENV DJANGO_ADMIN_URL=admin
+
+HEALTHCHECK --interval=60s --timeout=3s --start-interval=10s \
+  CMD curl -fsS http://localhost:${MESSAGES_FRONTEND_PORT}/health

src/frontend/nginx/nginx.conf.template

@@ -63,6 +63,12 @@ server {
         try_files /domain/[maildomainId]/signatures.html =404;
     }
 
+    location /health {
+        access_log off;
+        error_log off;
+        return 200 'ok';
+    }
+
     location = /404.html {
         internal;
     }