Tracer's active_span shorthand.

opentracing/harness/api_check.py

@@ -60,6 +60,15 @@ def is_parent(self, parent, span):
         """
         return False
 
+    def test_active_span(self):
+        tracer = self.tracer()
+        span = tracer.start_span('Fry')
+
+        if self.check_scope_manager():
+            assert tracer.active_span is None
+            with tracer.scope_manager.activate(span, True):
+                assert tracer.active_span is span
+
     def test_start_active_span(self):
         # the first usage returns a `Scope` that wraps a root `Span`
         tracer = self.tracer()

opentracing/tracer.py

@@ -51,6 +51,17 @@ def scope_manager(self):
         """ScopeManager accessor"""
         return self._scope_manager
 
+    @property
+    def active_span(self):
+        """Provides access to the the active Span. This is a shorthand for
+        Tracer.scope_manager.active.span, and None will be returned if
+        Scope.span is None.
+
+        :return: returns the active Span.
+        """
+        scope = self._scope_manager.active
+        return None if scope is None else scope.span
+
     def start_active_span(self,
                           operation_name,
                           finish_on_close,

tests/test_noop_tracer.py

@@ -31,3 +31,8 @@ def test_tracer():
     child = tracer.start_span(operation_name='child',
                               references=child_of(span))
     assert span == child
+
+
+def test_tracer_active_span():
+    tracer = Tracer()
+    assert tracer.active_span is tracer.scope_manager.active.span