feat: add MERGIFY_TRACEPARENT support (#148)

This allows the CI to propagate the job/jobstep span context to
pytest-mergify to link them together.



Fixes MRGFY-4951

Depends-On: #147

Author: sileht

pytest_mergify/__init__.py

@@ -15,6 +15,7 @@
 import _pytest.terminal
 import opentelemetry.trace
 from opentelemetry.semconv.trace import SpanAttributes
+from opentelemetry.trace.propagation.tracecontext import TraceContextTextMapPropagator
 
 from pytest_mergify import utils
 from pytest_mergify.tracer import MergifyTracer
@@ -86,11 +87,18 @@ def tracer(self) -> typing.Optional[opentelemetry.trace.Tracer]:
 
     def pytest_sessionstart(self, session: _pytest.main.Session) -> None:
         if self.tracer:
+            traceparent = os.environ.get("MERGIFY_TRACEPARENT")
+            if traceparent:
+                ctx = TraceContextTextMapPropagator().extract(
+                    carrier={"traceparent": traceparent}
+                )
+
             self.session_span = self.tracer.start_span(
                 "pytest session start",
                 attributes={
                     "test.scope": "session",
                 },
+                context=ctx if traceparent else None,
             )
         self.has_error = False
 

tests/test_spans.py

@@ -18,14 +18,34 @@ def test_span(
     }
 
 
-def test_session(
+def test_session_without_traceparent(
     pytester_with_spans: conftest.PytesterWithSpanT,
 ) -> None:
     result, spans = pytester_with_spans()
     assert spans is not None
     s = spans["pytest session start"]
     assert s.attributes == {"test.scope": "session"}
     assert s.status.status_code == opentelemetry.trace.StatusCode.OK
+    assert s.parent is None
+
+
+def test_session_with_traceparent(
+    pytester_with_spans: conftest.PytesterWithSpanT,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    monkeypatch.setenv(
+        "MERGIFY_TRACEPARENT", "00-80e1afed08e019fc1110464cfa66635c-7a085853722dc6d2-01"
+    )
+
+    result, spans = pytester_with_spans()
+    assert spans is not None
+    s = spans["pytest session start"]
+    assert s.attributes == {"test.scope": "session"}
+    assert s.status.status_code == opentelemetry.trace.StatusCode.OK
+    assert s.parent is not None
+    assert s.context.trace_id == 0x80E1AFED08E019FC1110464CFA66635C
+    assert s.parent.trace_id == 0x80E1AFED08E019FC1110464CFA66635C
+    assert s.parent.span_id == 0x7A085853722DC6D2
 
 
 def test_session_fail(