LITE-28135 add support for django

Author: Francesco Faraone

connect/eaas/runner/handlers/base.py

@@ -25,6 +25,7 @@ class ApplicationHandlerBase(ABC):
     def __init__(self, config):
         self._config = config
         self._logging_handler = None
+        self._django_settings_module = self.get_django_settings_module()
 
     @property
     def config(self):
@@ -70,7 +71,28 @@ def features(self):
     def variables(self):
         return self.get_variables()
 
+    @property
+    def django_settings_module(self):
+        return self._django_settings_module
+
+    def get_django_settings_module(self):
+        ep = next(
+            iter_entry_points('connect.eaas.ext', 'djsettings'),
+            None,
+        )
+        if ep:
+            get_settings = ep.load()
+            return get_settings()
+        return None
+
+    def load_django(self):
+        if self._django_settings_module:
+            os.environ.setdefault('DJANGO_SETTINGS_MODULE', self._django_settings_module)
+            import django
+            django.setup()
+
     def load_application(self, name):
+        self.load_django()
         ep = next(
             iter_entry_points('connect.eaas.ext', name),
             None,

connect/eaas/runner/handlers/web.py

@@ -5,6 +5,7 @@
 import functools
 import inspect
 import logging
+import os
 
 from fastapi import (
     FastAPI,
@@ -186,9 +187,41 @@ def get_asgi_application(self):
         static_root = self.get_application().get_static_root()
         if static_root:
             app.mount('/static', StaticFiles(directory=static_root), name='static')
+        if self.django_settings_module:
+            self.mount_django_apps(app)
 
         return app
 
+    def mount_django_apps(self, app):
+        from django.conf import settings  # noqa: I001
+        from django.core.exceptions import ImproperlyConfigured  # noqa: I001
+        from django.core.handlers.asgi import ASGIHandler  # noqa: I001
+        script_name = getattr(settings, 'FORCE_SCRIPT_NAME', None)
+        if not (
+            script_name
+            and script_name.startswith('/guest/')
+            and len(script_name) > len('/guest/')
+        ):
+            raise ImproperlyConfigured(
+                '`FORCE_SCRIPT_NAME` must be set and must start with "/guest/"',
+            )
+        static_root = self.get_application().get_static_root()
+        if not (
+            settings.STATIC_ROOT.startswith(static_root)
+            and len(settings.STATIC_ROOT) > len(static_root) - 1
+        ):
+            raise ImproperlyConfigured(
+                f'`STATIC_ROOT` must be a directory within {static_root}',
+            )
+        static_path = os.path.join(script_name, settings.STATIC_URL)
+        app.mount(
+            static_path,
+            StaticFiles(
+                directory=settings.STATIC_ROOT,
+            ),
+        )
+        app.mount(script_name, ASGIHandler())
+
     def setup_middlewares(self, app, middlewares):
         for middleware in middlewares:
             if inspect.isfunction(middleware):

connect/eaas/runner/workers/base.py

@@ -221,6 +221,8 @@ async def process_setup_response(self, data):
         reconfigured, then restart the tasks manager.
         """
         self.config.update_dynamic_config(data)
+        if self.handler.django_settings_module:
+            await self.invoke_hook('setup_django_settings')
         await self.trigger_event('on_startup')
         logger.info('Extension configuration has been updated.')
 
@@ -235,19 +237,22 @@ async def trigger_event(self, event):
                     return
                 self.on_shutdown_fired.value = 1
 
+        await self.invoke_hook(event)
+
+    async def invoke_hook(self, hook_name):
         application = self.handler.get_application()
-        event_handler = getattr(application, event, None)
+        hook = getattr(application, hook_name, None)
         if (
-            event_handler
-            and inspect.ismethod(event_handler)
-            and event_handler.__self__ is application
+            hook
+            and inspect.ismethod(hook)
+            and hook.__self__ is application
         ):
-            if inspect.iscoroutinefunction(event_handler):
-                await event_handler(self.handler.get_logger(), self.config.variables)
+            if inspect.iscoroutinefunction(hook):
+                await hook(self.handler.get_logger(), self.config.variables)
             else:
                 await asyncio.get_event_loop().run_in_executor(
                     None,
-                    event_handler,
+                    hook,
                     self.handler.get_logger(),
                     self.config.variables,
                 )