From acb6d9c4d1b5973accabb06f27018778e105dee6 Mon Sep 17 00:00:00 2001
From: chris meyers <chris.meyers.fsu@gmail.com>
Date: Fri, 21 Jun 2019 08:46:17 -0400
Subject: [PATCH] wrap smart inv cache update w/ advisory lock

* Two job templates that use the same smart inventory running at the
same time can easily race to recompute the smart inventory <-> host
mapping. In this case, bulk_create() can throw an error when racing.
* The per-smart-inventory advisory lock ensures that the state of the
system is consistent & that bulk_create() runs in isolation.
---
 awx/main/tasks.py | 39 ++++++++++++++++++++-------------------
 1 file changed, 20 insertions(+), 19 deletions(-)

diff --git a/awx/main/tasks.py b/awx/main/tasks.py
index d73737a4b3..08b7cf779d 100644
--- a/awx/main/tasks.py
+++ b/awx/main/tasks.py
@@ -602,25 +602,26 @@ def update_inventory_computed_fields(inventory_id, should_update_hosts=True):
 
 
 def update_smart_memberships_for_inventory(smart_inventory):
-    current = set(SmartInventoryMembership.objects.filter(inventory=smart_inventory).values_list('host_id', flat=True))
-    new = set(smart_inventory.hosts.values_list('id', flat=True))
-    additions = new - current
-    removals = current - new
-    if additions or removals:
-        with transaction.atomic():
-            if removals:
-                SmartInventoryMembership.objects.filter(inventory=smart_inventory, host_id__in=removals).delete()
-            if additions:
-                add_for_inventory = [
-                    SmartInventoryMembership(inventory_id=smart_inventory.id, host_id=host_id)
-                    for host_id in additions
-                ]
-                SmartInventoryMembership.objects.bulk_create(add_for_inventory)
-        logger.debug('Smart host membership cached for {}, {} additions, {} removals, {} total count.'.format(
-            smart_inventory.pk, len(additions), len(removals), len(new)
-        ))
-        return True  # changed
-    return False
+    with advisory_lock('update_smart_memberships_for_inventory-{}'.format(smart_inventory.id)):
+        current = set(SmartInventoryMembership.objects.filter(inventory=smart_inventory).values_list('host_id', flat=True))
+        new = set(smart_inventory.hosts.values_list('id', flat=True))
+        additions = new - current
+        removals = current - new
+        if additions or removals:
+            with transaction.atomic():
+                if removals:
+                    SmartInventoryMembership.objects.filter(inventory=smart_inventory, host_id__in=removals).delete()
+                if additions:
+                    add_for_inventory = [
+                        SmartInventoryMembership(inventory_id=smart_inventory.id, host_id=host_id)
+                        for host_id in additions
+                    ]
+                    SmartInventoryMembership.objects.bulk_create(add_for_inventory)
+            logger.debug('Smart host membership cached for {}, {} additions, {} removals, {} total count.'.format(
+                smart_inventory.pk, len(additions), len(removals), len(new)
+            ))
+            return True  # changed
+        return False
 
 
 @task()