Merge pull request #47 from instana/respect_my_authoritah!

Urllib3: Respect tracing state

Author: pglombardo

instana/instrumentation/urllib3.py

@@ -7,8 +7,13 @@
 
 @wrapt.patch_function_wrapper('urllib3', 'PoolManager.urlopen')
 def urlopen_with_instana(wrapped, instance, args, kwargs):
+    context = instana.internal_tracer.current_context()
+
+    # If we're not tracing, just return
+    if context is None:
+        return wrapped(*args, **kwargs)
+
     try:
-        context = instana.internal_tracer.current_context()
         span = instana.internal_tracer.start_span("urllib3", child_of=context)
         span.set_tag(ext.HTTP_URL, args[1])
         span.set_tag(ext.HTTP_METHOD, args[0])

instana/tracer.py

@@ -69,7 +69,10 @@ def start_span(
         return self.current_span
 
     def current_context(self):
-        return self.current_span.context
+        context = None
+        if self.current_span:
+            context = self.current_span.context
+        return context
 
     def inject(self, span_context, format, carrier):
         if format in self._propagators:

tests/test_urllib3.py

@@ -10,6 +10,7 @@ def setUp(self):
         self.http = urllib3.PoolManager()
         self.recorder = tracer.recorder
         self.recorder.clear_spans()
+        tracer.current_span = None
 
     def tearDown(self):
         """ Do nothing for now """
@@ -19,6 +20,9 @@ def test_vanilla_requests(self):
         r = self.http.request('GET', 'http://127.0.0.1:5000/')
         assert_equals(r.status, 200)
 
+        spans = self.recorder.queued_spans()
+        assert_equals(0, len(spans))
+
     def test_get_request(self):
         span = tracer.start_span("test")
         r = self.http.request('GET', 'http://127.0.0.1:5000/')