fix(s3): avoid cryptographic long-name suffixes

litellm/integrations/s3.py

@@ -1,7 +1,7 @@
 #### What this does ####
 #    On success + failure, log events to Supabase
 
-import hashlib
+import zlib
 from datetime import datetime
 from typing import Optional, cast
 
@@ -12,6 +12,15 @@ from litellm.types.utils import StandardLoggingPayload
 MAX_S3_FILENAME_STEM_LENGTH = 250
 
 
+def _long_filename_suffix(s3_file_name: str) -> str:
+    encoded_file_name = s3_file_name.encode("utf-8")
+    # Keep the suffix deterministic for collision avoidance without using a cryptographic hash.
+    return (
+        f"{zlib.crc32(encoded_file_name) & 0xFFFFFFFF:08x}"
+        f"{zlib.adler32(encoded_file_name) & 0xFFFFFFFF:08x}"
+    )
+
+
 class S3Logger:
     # Class variables or attributes
     def __init__(
@@ -189,9 +198,9 @@ def get_s3_object_key(
     s3_file_name: str,
 ) -> str:
     if len(s3_file_name) > MAX_S3_FILENAME_STEM_LENGTH:
-        digest = hashlib.sha256(s3_file_name.encode("utf-8")).hexdigest()[:16]
-        prefix_length = MAX_S3_FILENAME_STEM_LENGTH - len(digest) - 1
-        s3_file_name = f"{s3_file_name[:prefix_length]}_{digest}"
+        suffix = _long_filename_suffix(s3_file_name)
+        prefix_length = MAX_S3_FILENAME_STEM_LENGTH - len(suffix) - 1
+        s3_file_name = f"{s3_file_name[:prefix_length]}_{suffix}"
 
     s3_object_key = (
         (s3_path.rstrip("/") + "/" if s3_path else "")

tests/test_litellm/integrations/test_s3_v2.py

@@ -904,6 +904,24 @@ def test_get_s3_object_key_truncates_long_filename_components():
     assert filename.startswith(f"time-{start_time.strftime('%H-%M-%S-%f')}_resp_")
 
 
+def test_get_s3_object_key_uses_deterministic_suffixes_for_long_filename_components():
+    start_time = datetime(2026, 3, 26, 12, 51, 27, 995047)
+    shared_prefix = "resp_" + ("a" * 400)
+    first_file_name = f"time-{start_time.strftime('%H-%M-%S-%f')}_{shared_prefix}first"
+    second_file_name = (
+        f"time-{start_time.strftime('%H-%M-%S-%f')}_{shared_prefix}second"
+    )
+
+    first_key = get_s3_object_key("", "", start_time, first_file_name)
+    first_key_again = get_s3_object_key("", "", start_time, first_file_name)
+    second_key = get_s3_object_key("", "", start_time, second_file_name)
+
+    assert first_key == first_key_again
+    assert first_key != second_key
+    assert len(first_key.split("/")[-1]) <= 255
+    assert len(second_key.split("/")[-1]) <= 255
+
+
 def test_create_s3_batch_logging_element_limits_long_ids():
     start_time = datetime(2026, 3, 26, 12, 51, 27, 995047)
     long_response_id = "resp_" + ("a" * 400)