From 9c55539eb30cb5b2e5defb3455d81b340be9cb15 Mon Sep 17 00:00:00 2001
From: Maxim Kolyubyakin <maxim.kolyubyakin@ingrammicro.com>
Date: Tue, 29 Mar 2022 09:27:17 +0200
Subject: [PATCH] LITE-22733 Added lock for cache update in RQLFilterBackend

---
 dj_rql/drf/backend.py | 14 ++++++++++----
 requirements/dev.txt  |  2 +-
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/dj_rql/drf/backend.py b/dj_rql/drf/backend.py
index 6e673b0..ddea49a 100644
--- a/dj_rql/drf/backend.py
+++ b/dj_rql/drf/backend.py
@@ -1,12 +1,16 @@
 #
-#  Copyright © 2021 Ingram Micro Inc. All rights reserved.
+#  Copyright © 2022 Ingram Micro Inc. All rights reserved.
 #
+from threading import Lock
 
 from dj_rql.drf._utils import get_query
 
 from rest_framework.filters import BaseFilterBackend
 
 
+lock = Lock()
+
+
 class _FilterClassCache:
     CACHE = {}
 
@@ -46,10 +50,12 @@ def filter_queryset(self, request, queryset, view):
             cache_key = str(queryset.query) + query
 
             query_cache = self._get_or_init_cache(filter_class, view)
-            filters_result = query_cache.get(cache_key)
-            if not filters_result:
+            try:
+                filters_result = query_cache[cache_key]
+            except KeyError:
                 filters_result = filter_instance.apply_filters(query, request, view)
-                query_cache[cache_key] = filters_result
+                with lock:
+                    query_cache[cache_key] = filters_result
 
         else:
             filters_result = filter_instance.apply_filters(query, request, view)
diff --git a/requirements/dev.txt b/requirements/dev.txt
index fa5a9a5..17520ec 100644
--- a/requirements/dev.txt
+++ b/requirements/dev.txt
@@ -1,2 +1,2 @@
-lib-rql
+lib-rql>=1.1.1
 Django>=2.2.19