Fix for #1818 db files locked on Windows so not rm

  - Close db connections after startup metadata cache update
     - This seems to be the root cause of the latest bug from Friday when Kolibri
       would not delete files AFTER restarting (call to update_channel_metadata_cache locks all files in databases/ dir)
  - Disable ContentDBRoutingMiddleware for TasksViewSet worker views
    so they won't lock content DBs
  - The 'ATTACH DATABASE' statements seem to be fine when ContentDBRoutingMiddleware partially disabled
  - Close DB connections after ALL task runs
    - To fix can't-delete-after-import-from-Web bug
  - close_all DB connections before doing delete

Author: ivanistheone

kolibri/content/middleware.py

@@ -9,9 +9,12 @@ class ContentDBRoutingMiddleware(object):
     """
 
     def process_view(self, request, view_func, view_args, view_kwargs):
-        request.PREVIOUSLY_ACTIVE_CONTENT_DATABASE = get_active_content_database(return_none_if_not_set=True)
-        if "channel_id" in view_kwargs:
-            set_active_content_database(view_kwargs["channel_id"])
+        if view_func.__name__ == 'TasksViewSet':
+            pass  # Fix #1818.1: skip get_active_content_database for Task workers to avoid locking DB
+        else:
+            request.PREVIOUSLY_ACTIVE_CONTENT_DATABASE = get_active_content_database(return_none_if_not_set=True)
+            if "channel_id" in view_kwargs:
+                set_active_content_database(view_kwargs["channel_id"])
 
     def process_response(self, request, response):
         set_active_content_database(getattr(request, "PREVIOUSLY_ACTIVE_CONTENT_DATABASE", None))

kolibri/content/utils/annotation.py

@@ -32,3 +32,7 @@ def update_channel_metadata_cache():
         if ch_metadata_obj.last_updated is None:
             ch_metadata_obj.last_updated = local_now()
             ch_metadata_obj.save()
+
+    # Fix #1818.1 content database files get locked (this is called on startup)
+    from django.db import connections
+    connections.close_all()

kolibri/tasks/api.py

@@ -14,6 +14,7 @@
 import requests
 from django.core.management import call_command
 from django.http import Http404
+from django.db import connections
 from django.utils.translation import ugettext as _
 from kolibri.content.models import ChannelMetadataCache
 from kolibri.content.utils.channels import get_mounted_drives_with_channel_info
@@ -153,7 +154,7 @@ def _networkimport(channel_id, update_progress=None):
         "network",
         channel_id,
         update_progress=update_progress)
-
+    connections.close_all()  # close all DB connections (FIX for #1818)
 
 def _localimport(drive_id, update_progress=None):
     drives = get_mounted_drives_with_channel_info()
@@ -172,6 +173,7 @@ def _localimport(drive_id, update_progress=None):
             channel["id"],
             drive.datafolder,
             update_progress=update_progress)
+    connections.close_all()  # close all DB connections (FIX for #1818)
 
 
 def _localexport(drive_id, update_progress=None):
@@ -188,6 +190,7 @@ def _localexport(drive_id, update_progress=None):
             channel.id,
             drive.datafolder,
             update_progress=update_progress)
+    connections.close_all()  # close all DB connections (FIX for #1818)
 
 
 def _job_to_response(job):