Handle B3 trace_id and span_id correctly (open-telemetry#934)

Author: ocelotl

opentelemetry-sdk/src/opentelemetry/sdk/trace/propagation/b3_format.py

@@ -13,9 +13,11 @@
 # limitations under the License.
 
 import typing
+from re import compile as re_compile
 
 import opentelemetry.trace as trace
 from opentelemetry.context import Context
+from opentelemetry.sdk.trace import generate_span_id, generate_trace_id
 from opentelemetry.trace.propagation.httptextformat import (
     Getter,
     HTTPTextFormat,
@@ -37,6 +39,8 @@ class B3Format(HTTPTextFormat):
     SAMPLED_KEY = "x-b3-sampled"
     FLAGS_KEY = "x-b3-flags"
     _SAMPLE_PROPAGATE_VALUES = set(["1", "True", "true", "d"])
+    _trace_id_regex = re_compile(r"[\da-fA-F]{16}|[\da-fA-F]{32}")
+    _span_id_regex = re_compile(r"[\da-fA-F]{16}")
 
     def extract(
         self,
@@ -95,19 +99,32 @@ def extract(
                 or flags
             )
 
+        if (
+            self._trace_id_regex.fullmatch(trace_id) is None
+            or self._span_id_regex.fullmatch(span_id) is None
+        ):
+            trace_id = generate_trace_id()
+            span_id = generate_span_id()
+            sampled = "0"
+
+        else:
+            trace_id = int(trace_id, 16)
+            span_id = int(span_id, 16)
+
         options = 0
         # The b3 spec provides no defined behavior for both sample and
         # flag values set. Since the setting of at least one implies
         # the desire for some form of sampling, propagate if either
         # header is set to allow.
         if sampled in self._SAMPLE_PROPAGATE_VALUES or flags == "1":
             options |= trace.TraceFlags.SAMPLED
+
         return trace.set_span_in_context(
             trace.DefaultSpan(
                 trace.SpanContext(
                     # trace an span ids are encoded in hex, so must be converted
-                    trace_id=int(trace_id, 16),
-                    span_id=int(span_id, 16),
+                    trace_id=trace_id,
+                    span_id=span_id,
                     is_remote=True,
                     trace_flags=trace.TraceFlags(options),
                     trace_state=trace.TraceState(),

opentelemetry-sdk/tests/trace/propagation/test_b3_format.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 import unittest
+from unittest.mock import patch
 
 import opentelemetry.sdk.trace as trace
 import opentelemetry.sdk.trace.propagation.b3_format as b3_format
@@ -245,6 +246,50 @@ def test_missing_trace_id(self):
         span_context = trace_api.get_current_span(ctx).get_context()
         self.assertEqual(span_context.trace_id, trace_api.INVALID_TRACE_ID)
 
+    @patch("opentelemetry.sdk.trace.propagation.b3_format.generate_trace_id")
+    @patch("opentelemetry.sdk.trace.propagation.b3_format.generate_span_id")
+    def test_invalid_trace_id(
+        self, mock_generate_span_id, mock_generate_trace_id
+    ):
+        """If a trace id is invalid, generate a trace id."""
+
+        mock_generate_trace_id.configure_mock(return_value=1)
+        mock_generate_span_id.configure_mock(return_value=2)
+
+        carrier = {
+            FORMAT.TRACE_ID_KEY: "abc123",
+            FORMAT.SPAN_ID_KEY: self.serialized_span_id,
+            FORMAT.FLAGS_KEY: "1",
+        }
+
+        ctx = FORMAT.extract(get_as_list, carrier)
+        span_context = trace_api.get_current_span(ctx).get_context()
+
+        self.assertEqual(span_context.trace_id, 1)
+        self.assertEqual(span_context.span_id, 2)
+
+    @patch("opentelemetry.sdk.trace.propagation.b3_format.generate_trace_id")
+    @patch("opentelemetry.sdk.trace.propagation.b3_format.generate_span_id")
+    def test_invalid_span_id(
+        self, mock_generate_span_id, mock_generate_trace_id
+    ):
+        """If a span id is invalid, generate a trace id."""
+
+        mock_generate_trace_id.configure_mock(return_value=1)
+        mock_generate_span_id.configure_mock(return_value=2)
+
+        carrier = {
+            FORMAT.TRACE_ID_KEY: self.serialized_trace_id,
+            FORMAT.SPAN_ID_KEY: "abc123",
+            FORMAT.FLAGS_KEY: "1",
+        }
+
+        ctx = FORMAT.extract(get_as_list, carrier)
+        span_context = trace_api.get_current_span(ctx).get_context()
+
+        self.assertEqual(span_context.trace_id, 1)
+        self.assertEqual(span_context.span_id, 2)
+
     def test_missing_span_id(self):
         """If a trace id is missing, populate an invalid trace id."""
         carrier = {