SNOW-1362666: improve random string generation (#2034)

DESCRIPTION.md

@@ -8,6 +8,9 @@ Source code is also available at: https://github.com/snowflakedb/snowflake-conne
 
 # Release Notes
 
+- v3.12.2 (TBD)
+  - Improved implementation of `snowflake.connector.util_text.random_string` to avoid collisions.
+
 - v3.12.1(August 20,2024)
   - Fixed a bug that logged the session token when renewing a session.
   - Fixed a bug where disabling client telemetry did not work.

src/snowflake/connector/util_text.py

@@ -282,5 +282,5 @@ def random_string(
         suffix: Suffix to add to random string generated.
         choices: A generator of things to choose from.
     """
-    random_part = "".join([random.choice(choices) for _ in range(length)])
+    random_part = "".join([random.Random().choice(choices) for _ in range(length)])
     return "".join([prefix, random_part, suffix])

test/unit/test_text_util.py

@@ -0,0 +1,37 @@
+#
+# Copyright (c) 2012-2023 Snowflake Computing Inc. All rights reserved.
+#
+
+import concurrent.futures
+import random
+
+import pytest
+
+try:
+    from snowflake.connector.util_text import random_string
+except ImportError:
+    pass
+
+pytestmark = pytest.mark.skipolddriver  # old test driver tests won't run this module
+
+
+def test_random_string_generation_with_same_global_seed():
+    random.seed(42)
+    random_string1 = random_string()
+    random.seed(42)
+    random_string2 = random_string()
+    assert (
+        isinstance(random_string1, str)
+        and isinstance(random_string2, str)
+        and random_string1 != random_string2
+    )
+
+    def get_random_string():
+        random.seed(42)
+        return random_string()
+
+    with concurrent.futures.ThreadPoolExecutor(max_workers=5) as executor:
+        # Submit tasks to the pool and get future objects
+        futures = [executor.submit(get_random_string) for _ in range(5)]
+        res = [f.result() for f in futures]
+        assert len(set(res)) == 5  # no duplicate string