Revert "Apply migration flag check to task manager"

This reverts commit a0910eb6de.

awx/main/middleware.py

@@ -13,17 +13,18 @@ import urllib.parse
 from django.conf import settings
 from django.contrib.auth.models import User
 from django.db.models.signals import post_save
-from django.db import IntegrityError
+from django.db.migrations.executor import MigrationExecutor
+from django.db import IntegrityError, connection
 from django.utils.functional import curry
 from django.shortcuts import get_object_or_404, redirect
 from django.apps import apps
+from django.core.cache import cache
 from django.utils.deprecation import MiddlewareMixin
 from django.utils.translation import ugettext_lazy as _
 from django.urls import reverse, resolve
 
 from awx.main.models import ActivityStream
 from awx.main.utils.named_url_graph import generate_graph, GraphNode
-from awx.main.utils.db import migration_in_progress_check_or_relase
 from awx.conf import fields, register
 
 
@@ -213,7 +214,11 @@ class URLModificationMiddleware(MiddlewareMixin):
 class MigrationRanCheckMiddleware(MiddlewareMixin):
 
     def process_request(self, request):
-        if migration_in_progress_check_or_relase():
-            if getattr(resolve(request.path), 'url_name', '') == 'migrations_notran':
-                return
-            return redirect(reverse("ui:migrations_notran"))
+        if cache.get('migration_in_progress', False):
+            executor = MigrationExecutor(connection)
+            plan = executor.migration_plan(executor.loader.graph.leaf_nodes())
+            if not bool(plan):
+                logger.info('Detected that migration finished, migration page taken down.')
+                cache.delete('migration_in_progress')
+            elif getattr(resolve(request.path), 'url_name', '') != 'migrations_notran':
+                return redirect(reverse("ui:migrations_notran"))