Fix subspan export bug (census-instrumentation#545)

Fix a bug in ContextTracer that duplicated the root span on export.

Author: c24t

opencensus/trace/tracers/context_tracer.py

@@ -152,27 +152,25 @@ def get_span_datas(self, span):
         :rtype: list of opencensus.trace.span_data.SpanData
         :return list of SpanData tuples
         """
-        span_tree = list(iter(span))
         span_datas = [
             span_data_module.SpanData(
-                name=span.name,
+                name=ss.name,
                 context=self.span_context,
-                span_id=span.span_id,
-                parent_span_id=span.parent_span.span_id if
-                span.parent_span else None,
-                attributes=span.attributes,
-                start_time=span.start_time,
-                end_time=span.end_time,
-                child_span_count=len(span.children),
-                stack_trace=span.stack_trace,
-                time_events=span.time_events,
-                links=span.links,
-                status=span.status,
-                same_process_as_parent_span=span.same_process_as_parent_span,
-                span_kind=span.span_kind
-
+                span_id=ss.span_id,
+                parent_span_id=ss.parent_span.span_id if
+                ss.parent_span else None,
+                attributes=ss.attributes,
+                start_time=ss.start_time,
+                end_time=ss.end_time,
+                child_span_count=len(ss.children),
+                stack_trace=ss.stack_trace,
+                time_events=ss.time_events,
+                links=ss.links,
+                status=ss.status,
+                same_process_as_parent_span=ss.same_process_as_parent_span,
+                span_kind=ss.span_kind
             )
-            for ss in span_tree
+            for ss in span
         ]
 
         return span_datas

tests/system/trace/basic_trace/basic_trace_system_test.py

@@ -16,9 +16,7 @@
 
 
 def func_to_trace():
-    import time
     print('Test simple tracing...')
-    time.sleep(2)
 
 
 class TestBasicTrace(unittest.TestCase):
@@ -65,8 +63,15 @@ def test_tracer(self):
         self.assertEqual(trace_json.get('traceId'), trace_id)
         self.assertEqual(len(spans), 2)
 
+        self.assertSetEqual(
+            {ss['displayName']['value'] for ss in spans},
+            {'child_span', 'root_span'})
+
         for span in spans:
-            if span.get('displayName').get('value') == 'root_span':
-                self.assertEqual(str(span.get('parentSpanId')), span_id)
+            if span['displayName']['value'] == 'root_span':
+                self.assertEqual(span['parentSpanId'], span_id)
+                self.assertEqual(span['childSpanCount'], 1)
             else:
-                self.assertEqual(span.get('parentSpanId'), parent_span_id)
+                self.assertEqual(span['displayName']['value'], 'child_span')
+                self.assertEqual(span['parentSpanId'], parent_span_id)
+                self.assertEqual(span['childSpanCount'], 0)

tests/unit/trace/tracers/test_context_tracer.py

@@ -67,6 +67,44 @@ def test_finish_with_spans(self):
 
         self.assertEqual(tracer._spans_list, [])
 
+    def test_finish_with_tracer_subspans(self):
+        tracer = context_tracer.ContextTracer()
+        parent = tracer.start_span('parent')
+        child = tracer.start_span('child')
+        self.assertEqual(child.parent_span, parent)
+        tracer.exporter = mock.Mock()
+        tracer.finish()
+
+        self.assertEqual(tracer.exporter.export.call_count, 2)
+        [[[[c_sd]], _], [[[p_sd]], _]] = tracer.exporter.export.call_args_list
+
+        self.assertEqual(p_sd.span_id, parent.span_id)
+        self.assertIsNone(parent.parent_span.span_id)
+        self.assertIsNone(p_sd.parent_span_id)
+        self.assertEqual(c_sd.span_id, child.span_id)
+        self.assertEqual(c_sd.parent_span_id, parent.span_id)
+
+        self.assertEqual(tracer._spans_list, [])
+
+    def test_finish_with_span_subspans(self):
+        tracer = context_tracer.ContextTracer()
+        parent = tracer.start_span('parent')
+        child = parent.span('child')
+        self.assertEqual(child.parent_span, parent)
+        tracer.exporter = mock.Mock()
+        tracer.finish()
+
+        self.assertEqual(tracer.exporter.export.call_count, 1)
+        [[[[c_sd, p_sd]], _]] = tracer.exporter.export.call_args_list
+
+        self.assertEqual(p_sd.span_id, parent.span_id)
+        self.assertIsNone(parent.parent_span.span_id)
+        self.assertIsNone(p_sd.parent_span_id)
+        self.assertEqual(c_sd.span_id, child.span_id)
+        self.assertEqual(c_sd.parent_span_id, parent.span_id)
+
+        self.assertEqual(tracer._spans_list, [])
+
     def test_end_leftover_spans(self):
         tracer = context_tracer.ContextTracer()
         tracer._spans_list = [span.Span(name='span')]