signal backend, app cleanup

manage.py

@@ -1,11 +1,35 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 """Django's command-line utility for administrative tasks."""
 import os
 import sys
 
 
+def activate_venv(base):
+    if os.path.exists(base):
+        old_os_path = os.environ.get("PATH", "")
+        os.environ["PATH"] = os.path.join(base, "bin") + os.pathsep + old_os_path
+        version = "%s.%s" % (sys.version_info.major, sys.version_info.minor)
+        site_packages = os.path.join(base, "lib", "python%s" % version, "site-packages")
+        prev_sys_path = list(sys.path)
+        import site
+
+        site.addsitedir(site_packages)
+        sys.real_prefix = sys.prefix
+        sys.prefix = base
+        # Move the added items to the front of the path:
+        new_sys_path = []
+        for item in list(sys.path):
+            if item not in prev_sys_path:
+                new_sys_path.append(item)
+                sys.path.remove(item)
+        sys.path[:0] = new_sys_path
+
+
 def main():
     """Run administrative tasks."""
+    root_dir = os.path.normpath(os.path.abspath(os.path.dirname(__file__)))
+    activate_venv(os.path.normpath(os.path.join(root_dir, "venv")))
+
     os.environ.setdefault("DJANGO_SETTINGS_MODULE", "app.settings")
     try:
         from django.core.management import execute_from_command_line