we don't need thread locks for SDK tracing context

sdk/core/azure-core/azure/core/tracing/context.py

@@ -29,8 +29,8 @@ class ContextProtocol(Protocol):
      Implements set and get variables in a thread safe way.
      """
 
-    def __init__(self, name, default, lock):
-        # type: (string, Any, threading.Lock) -> None
+    def __init__(self, name, default):
+        # type: (string, Any) -> None
         pass
 
     def clear(self):
@@ -54,11 +54,10 @@ class _AsyncContext(object):
     Uses contextvars to set and get variables globally in a thread safe way.
     """
 
-    def __init__(self, name, default, lock):
+    def __init__(self, name, default):
         self.name = name
         self.contextvar = contextvars.ContextVar(name)
         self.default = default if callable(default) else (lambda: default)
-        self.lock = lock
 
     def clear(self):
         # type: () -> None
@@ -78,8 +77,7 @@ def get(self):
     def set(self, value):
         # type: (Any) -> None
         """Set the value in the context."""
-        with self.lock:
-            self.contextvar.set(value)
+        self.contextvar.set(value)
 
 
 class _ThreadLocalContext(object):
@@ -88,11 +86,10 @@ class _ThreadLocalContext(object):
     """
     _thread_local = threading.local()
 
-    def __init__(self, name, default, lock):
-        # type: (str, Any, threading.Lock) -> None
+    def __init__(self, name, default):
+        # type: (str, Any) -> None
         self.name = name
         self.default = default if callable(default) else (lambda: default)
-        self.lock = lock
 
     def clear(self):
         # type: () -> None
@@ -112,16 +109,14 @@ def get(self):
     def set(self, value):
         # type: (Any) -> None
         """Set the value in the context."""
-        with self.lock:
-            setattr(self._thread_local, self.name, value)
+        setattr(self._thread_local, self.name, value)
 
 
-class TracingContext:
-    _lock = threading.Lock()
-
+class TracingContext(object):
     def __init__(self):
         # type: () -> None
-        self.current_span = TracingContext._get_context_class("current_span", None)
+        context_class = _AsyncContext if contextvars else _ThreadLocalContext
+        self.current_span = context_class("current_span", None)
 
     def with_current_context(self, func):
         # type: (Callable[[Any], Any]) -> Any
@@ -146,17 +141,4 @@ def call_with_current_context(*args, **kwargs):
 
         return call_with_current_context
 
-    @classmethod
-    def _get_context_class(cls, name, default_val):
-        # type: (str, Any) -> ContextProtocol
-        """
-        Returns an instance of the the context class that stores the variable.
-        :param name: The key to store the variable in the context class
-        :param default_val: The default value of the variable if unset
-        :return: An instance that implements the context protocol class
-        """
-        context_class = _AsyncContext if contextvars else _ThreadLocalContext
-        return context_class(name, default_val, cls._lock)
-
-
 tracing_context = TracingContext()

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

@@ -34,19 +34,14 @@ def __exit__(self, exc_type, exc_val, exc_tb):
 
 
 class TestContext(unittest.TestCase):
-    def test_get_context_class(self):
-        with ContextHelper():
-            slot = tracing_context._get_context_class("temp", 1)
-            assert slot.get() == 1
-            slot.set(2)
-            assert slot.get() == 2
-
     def test_current_span(self):
         with ContextHelper():
-            assert tracing_context.current_span.get() is None
+            assert not tracing_context.current_span.get()
             val = mock.Mock(spec=AbstractSpan)
             tracing_context.current_span.set(val)
             assert tracing_context.current_span.get() == val
+            tracing_context.current_span.clear()
+            assert not tracing_context.current_span.get()
 
     def test_with_current_context(self):
         with ContextHelper(tracer_to_use=mock.Mock(AbstractSpan)):