release note

ddtrace/propagation/http.py

@@ -537,11 +537,11 @@ def _inject(span_context, headers):
             return
 
         sampling_priority = span_context.sampling_priority
-        sampling_priority_hex = "00000001" if sampling_priority and sampling_priority >= 1 else "00000000"
+        sampling_priority_hex = "01" if sampling_priority and sampling_priority >= AUTO_KEEP else "00"
         # There is currently only a single version so we always start with 00
         traceparent = "{}-{}-{}-{}".format(
             "00",
-            "0000000000000000" + hex(span_context.trace_id)[2:],
+            "0000000000000000" + hex(span_context.trace_id)[2:],  # we slice off the "0x" that hex() prepends
             hex(span_context.span_id)[2:],
             sampling_priority_hex,
         )
@@ -566,7 +566,7 @@ def _extract(headers):
                 trace_id = int(trace_id_hex[-16], 16 & 0xFFFFFFFFFFFF)
                 span_id = int(span_id_hex, 16 & 0xFFFFFFFFFFFF)
                 # there's only one trace flag, which denotes sampling priority was set to keep
-                sampling_priority = AUTO_KEEP if trace_flags == "00000001" else 0
+                sampling_priority = AUTO_KEEP if trace_flags == "01" else AUTO_REJECT
             else:
                 log.warning("unsupported traceparent version:%s", version)
                 return None
@@ -657,6 +657,10 @@ def my_controller(url, headers):
                 context = _B3SingleHeader._extract(normalized_headers)
                 if context is not None:
                     return context
+            if PROPAGATION_STYLE_W3C in config._propagation_style_extract:
+                context = _W3CTraceContext._extract(normalized_headers)
+                if context is not None:
+                    return context
         except Exception:
             log.debug("error while extracting context propagation headers", exc_info=True)
         return Context()

releasenotes/notes/add-w3c-traceparent-propagation-789324b2e1326f0e.yaml

@@ -0,0 +1,8 @@
+---
+features:
+  - |
+    Add support for injecting and extracting W3C traceparent propagation header.
+
+    See :ref:`DD_TRACE_PROPAGATION_STYLE_EXTRACT <dd-trace-propagation-style-extract>` and
+    :ref:`DD_TRACE_PROPAGATION_STYLE_INJECT <dd-trace-propagation-style-inject>`
+    configuration documentation to enable.