Cache redis version in the connection object (#1742)

rq/utils.py

@@ -303,7 +303,14 @@ def get_version(connection: 'Redis'):
         connection (Redis): The Redis connection.
     """
     try:
-        return tuple(int(i) for i in connection.info("server")["redis_version"].split('.')[:3])
+        # Getting the connection info for each job tanks performance, we can cache it on the connection object
+        if not getattr(connection, "__rq_redis_server_version", None):
+            setattr(
+                connection,
+                "__rq_redis_server_version",
+                tuple(int(i) for i in connection.info("server")["redis_version"].split('.')[:3])
+            )
+        return getattr(connection, "__rq_redis_server_version")
     except ResponseError:  # fakeredis doesn't implement Redis' INFO command
         return (5, 0, 9)
 

tests/test_utils.py

@@ -1,5 +1,6 @@
 import re
 import datetime
+from unittest.mock import Mock
 
 from redis import Redis
 
@@ -85,6 +86,15 @@ class TestUtils(RQTestCase):
                 return {'redis_version': '3.0.7.9'}
         self.assertEqual(get_version(DummyRedis()), (3, 0, 7))
 
+    def test_get_redis_version_gets_cached(self):
+        """Ensure get_version works properly"""
+        # Parses 3 digit version numbers correctly
+        redis = Mock(spec=['info'])
+        redis.info = Mock(return_value={'redis_version': '4.0.8'})
+        self.assertEqual(get_version(redis), (4, 0, 8))
+        self.assertEqual(get_version(redis), (4, 0, 8))
+        redis.info.assert_called_once()
+
     def test_ceildiv_even(self):
         """When a number is evenly divisible by another ceildiv returns the quotient"""
         dividend = 12