1542. Allow missing carrier headers to continue without raising AttributeError (#1545)

Author: ehiggs

CHANGELOG.md

@@ -6,14 +6,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased](https://github.com/open-telemetry/opentelemetry-python/compare/v0.17b0...HEAD)
 
-=======
 ### Added
 - Added `end_on_exit` argument to `start_as_current_span`
   ([#1519](https://github.com/open-telemetry/opentelemetry-python/pull/1519)])
 - Add `Span.set_attributes` method to set multiple values with one call
   ([#1520](https://github.com/open-telemetry/opentelemetry-python/pull/1520))
 - Make sure Resources follow semantic conventions
   ([#1480](https://github.com/open-telemetry/opentelemetry-python/pull/1480))
+- Allow missing carrier headers to continue without raising AttributeError
+  ([#1545](https://github.com/open-telemetry/opentelemetry-python/pull/1545))
 
 ## [0.17b0](https://github.com/open-telemetry/opentelemetry-python/releases/tag/v0.17b0) - 2021-01-20
 

propagator/opentelemetry-propagator-jaeger/src/opentelemetry/propagators/jaeger/__init__.py

@@ -45,9 +45,10 @@ def extract(
 
         if context is None:
             context = get_current()
-        fields = _extract_first_element(
-            getter.get(carrier, self.TRACE_ID_KEY)
-        ).split(":")
+        header = getter.get(carrier, self.TRACE_ID_KEY)
+        if not header:
+            return trace.set_span_in_context(trace.INVALID_SPAN, context)
+        fields = _extract_first_element(header).split(":")
 
         context = self._extract_baggage(getter, carrier, context)
         if len(fields) != 4:

propagator/opentelemetry-propagator-jaeger/tests/test_jaeger_propagator.py

@@ -83,6 +83,13 @@ def test_extract_valid_span(self):
         self.assertEqual(span_context.trace_id, self.trace_id)
         self.assertEqual(span_context.span_id, self.span_id)
 
+    def test_missing_carrier(self):
+        old_carrier = {}
+        ctx = FORMAT.extract(carrier_getter, old_carrier)
+        span_context = trace_api.get_current_span(ctx).get_span_context()
+        self.assertEqual(span_context.trace_id, trace_api.INVALID_TRACE_ID)
+        self.assertEqual(span_context.span_id, trace_api.INVALID_SPAN_ID)
+
     def test_trace_id(self):
         old_carrier = {FORMAT.TRACE_ID_KEY: self.serialized_uber_trace_id}
         _, new_carrier = get_context_new_carrier(old_carrier)