Use file lock around Chroma client initialization (#3181)

This commit fixes a bug with concurrent processess and Chroma where
`table collections already exists` (and similar) were raised.

https://cookbook.chromadb.dev/core/system_constraints/

tests/utilities/test_chromadb_utils.py

@@ -1,16 +1,27 @@
+import multiprocessing
+import tempfile
 import unittest
-from typing import Any, Dict, List, Union
 
-import pytest
+from chromadb.config import Settings
+from unittest.mock import patch, MagicMock
 
 from crewai.utilities.chromadb import (
     MAX_COLLECTION_LENGTH,
     MIN_COLLECTION_LENGTH,
     is_ipv4_pattern,
     sanitize_collection_name,
+    create_persistent_client,
 )
 
 
+def persistent_client_worker(path, queue):
+    try:
+        create_persistent_client(path=path)
+        queue.put(None)
+    except Exception as e:
+        queue.put(e)
+
+
 class TestChromadbUtils(unittest.TestCase):
     def test_sanitize_collection_name_long_name(self):
         """Test sanitizing a very long collection name."""
@@ -79,3 +90,34 @@ class TestChromadbUtils(unittest.TestCase):
             self.assertLessEqual(len(sanitized), MAX_COLLECTION_LENGTH)
             self.assertTrue(sanitized[0].isalnum())
             self.assertTrue(sanitized[-1].isalnum())
+
+    def test_create_persistent_client_passes_args(self):
+        with patch(
+            "crewai.utilities.chromadb.PersistentClient"
+        ) as mock_persistent_client, tempfile.TemporaryDirectory() as tmpdir:
+            mock_instance = MagicMock()
+            mock_persistent_client.return_value = mock_instance
+
+            settings = Settings(allow_reset=True)
+            client = create_persistent_client(path=tmpdir, settings=settings)
+
+            mock_persistent_client.assert_called_once_with(
+                path=tmpdir, settings=settings
+            )
+            self.assertIs(client, mock_instance)
+
+    def test_create_persistent_client_process_safe(self):
+        with tempfile.TemporaryDirectory() as tmpdir:
+            queue = multiprocessing.Queue()
+            processes = [
+                multiprocessing.Process(
+                    target=persistent_client_worker, args=(tmpdir, queue)
+                )
+                for _ in range(5)
+            ]
+
+            [p.start() for p in processes]
+            [p.join() for p in processes]
+
+            errors = [queue.get(timeout=5) for _ in processes]
+            self.assertTrue(all(err is None for err in errors))