[Core] Add tracing impl detection function caching (#43338)

Signed-off-by: Paul Van Eck <[email protected]>

Author: pvaneck

sdk/core/azure-core/CHANGELOG.md

@@ -1,6 +1,6 @@
 # Release History
 
-## 1.35.2 (Unreleased)
+## 1.36.0 (Unreleased)
 
 ### Features Added
 
@@ -15,7 +15,8 @@
 ### Other Changes
 
 - Updated `BearerTokenCredentialPolicy` and `AsyncBearerTokenCredentialPolicy` to set the `enable_cae` parameter to `True` by default. This change enables Continuous Access Evaluation (CAE) for all token requests made through these policies.  #42941
-- Removed `six` as a dependency since it was unused.
+- Removed `six` as a dependency since it was unused. #39962
+- Added caching to the tracing implementation detection function to prevent potential performance issues from repeated import attempts. #43338
 
 ## 1.35.1 (2025-09-11)
 

sdk/core/azure-core/azure/core/_version.py

@@ -9,4 +9,4 @@
 # regenerated.
 # --------------------------------------------------------------------------
 
-VERSION = "1.35.2"
+VERSION = "1.36.0"

sdk/core/azure-core/azure/core/exceptions.py

@@ -195,7 +195,7 @@ class ODataV4Format:
         }
 
     :param dict json_object: A Python dict representing a ODataV4 JSON
-    :ivar str ~.code: Its value is a service-defined error code.
+    :ivar str code: Its value is a service-defined error code.
      This code serves as a sub-status for the HTTP error code specified in the response.
     :ivar str message: Human-readable, language-dependent representation of the error.
     :ivar str target: The target of the particular error (for example, the name of the property in error).

sdk/core/azure-core/azure/core/settings.py

@@ -28,6 +28,7 @@
 from __future__ import annotations
 from collections import namedtuple
 from enum import Enum
+from functools import cache
 import logging
 import os
 from typing import (
@@ -207,6 +208,7 @@ def _get_opentelemetry_span() -> Optional[Type[AbstractSpan]]:
 }
 
 
+@cache
 def convert_tracing_impl(value: Optional[Union[str, Type[AbstractSpan]]]) -> Optional[Type[AbstractSpan]]:
     """Convert a string to AbstractSpan
 

sdk/core/azure-core/tests/test_settings.py

@@ -174,6 +174,32 @@ def test_convert_azure_cloud(self):
         with pytest.raises(ValueError):
             m.convert_azure_cloud(10)
 
+    def test_convert_tracing_impl_bad(self):
+        with pytest.raises(ValueError):
+            m.convert_tracing_impl("foo")
+
+    def test_convert_tracing_impl_caching(self):
+        m.convert_tracing_impl.cache_clear()
+        with patch.dict(
+            m._tracing_implementation_dict,
+            {
+                "opentelemetry": MagicMock(wraps=m._get_opentelemetry_span),
+                "opencensus": MagicMock(wraps=m._get_opencensus_span),
+            },
+        ) as patched_dict:
+            mock_method = patched_dict["opentelemetry"]
+            impl1 = m.convert_tracing_impl("opentelemetry")
+            impl2 = m.convert_tracing_impl("opentelemetry")
+            assert impl1 is impl2
+            assert mock_method.call_count == 1
+
+            mock_method = patched_dict["opencensus"]
+            impl1 = m.convert_tracing_impl("opencensus")
+            impl2 = m.convert_tracing_impl("opencensus")
+            assert impl1 is impl2
+            assert mock_method.call_count == 1
+        m.convert_tracing_impl.cache_clear()
+
 
 _standard_settings = ["log_level", "tracing_enabled"]