06/16 Phase 6 (continue)

app/__init__.py

@@ -1,8 +1,13 @@
 """Application factory."""
-from flask import Flask, render_template
+from flask import Flask, render_template, request
+from flask_login import current_user
 from app.config import get_config
 from app.extensions import (db, migrate, login_manager, csrf, babel, limiter)
 
+_MAINTENANCE_EXEMPT_ENDPOINTS = {
+    "static", "main.healthz", "auth.login", "auth.logout", "payments.webhook",
+}
+
 
 def create_app(config_object=None):
     app = Flask(__name__)
@@ -14,6 +19,7 @@ def create_app(config_object=None):
     _register_blueprints(app)
     _register_errorhandlers(app)
     _register_context(app)
+    _register_hooks(app)
     _register_cli(app)
 
     return app
@@ -115,6 +121,20 @@ def _register_context(app):
         }
 
 
+def _register_hooks(app):
+    @app.before_request
+    def check_maintenance():
+        from app.services.settings import get_setting
+        if not get_setting("maintenance_mode", False):
+            return None
+        if current_user.is_authenticated and getattr(current_user, "is_admin", False):
+            return None
+        ep = request.endpoint or ""
+        if ep in _MAINTENANCE_EXEMPT_ENDPOINTS or ep.startswith("admin."):
+            return None
+        return render_template("errors/maintenance.html"), 503
+
+
 def _register_cli(app):
     @app.cli.command("expire-listings")
     def expire_listings_cmd():