Omit tracing metadata outside recording spans

docs/migration/to-2.x.md

@@ -20,3 +20,9 @@ metrics. Existing user-defined exclusions still apply. Dashboards and alerts
 that previously included these requests may show lower request totals and
 different latency percentiles. Review thresholds that were based on the old
 traffic mix.
+
+## Trace context in JSON logs
+
+JSON log lines include `tracing` only when emitted inside a recording
+OpenTelemetry span. The object contains `span_id` and `trace_id`.
+Update log parsers to treat `tracing` as optional.

lite_bootstrap/instruments/logging_instrument.py

@@ -41,7 +41,7 @@ def format(self, record: logging.LogRecord) -> str:
     def tracer_injection(_: "WrappedLogger", __: str, event_dict: "EventDict") -> "EventDict":
         current_span = trace.get_current_span()
         if not current_span.is_recording():
-            event_dict["tracing"] = {}
+            event_dict.pop("tracing", None)
             return event_dict
 
         current_span_context = current_span.get_span_context()

tests/instruments/test_logging_instrument.py

@@ -8,7 +8,7 @@
 
 import pytest
 import structlog
-from opentelemetry.trace import get_tracer
+from opentelemetry.trace import format_span_id, format_trace_id, get_tracer
 
 from lite_bootstrap.exceptions import TeardownError
 from lite_bootstrap.instruments.logging_instrument import LoggingConfig, LoggingInstrument
@@ -45,40 +45,29 @@ def test_logging_instrument_simple(logging_mock: LoggingMock) -> None:
         logging_instrument.teardown()
 
 
-def test_logging_instrument_tracer_injection(logging_mock: LoggingMock) -> None:
-    logging_instrument = LoggingInstrument(
-        bootstrap_config=LoggingConfig(
-            logging_unset_handlers=["uvicorn"],
-            logging_extra_processors=[logging_mock],
-        )
-    )
+def test_logging_instrument_tracer_injection(capsys: pytest.CaptureFixture[str]) -> None:
+    logging_instrument = LoggingInstrument(bootstrap_config=LoggingConfig())
     opentelemetry_instrument = OpenTelemetryInstrument(
-        bootstrap_config=OpenTelemetryConfig(
-            opentelemetry_log_traces=True,
-        )
+        bootstrap_config=OpenTelemetryConfig(opentelemetry_log_traces=True)
     )
     try:
         logging_instrument.bootstrap()
         opentelemetry_instrument.bootstrap()
 
         logger = structlog.getLogger(__name__)
-        tracer = get_tracer(__name__)
-        logger.info("testing tracer injection without spans")
-        with tracer.start_as_current_span("my_fake_span") as span:
-            logger.info("testing tracer injection without span attributes")
-            span.set_attribute("example_attribute", "value")
-            span.add_event("example_event", {"event_attr": 1})
-            logger.info("testing tracer injection with span attributes")
-
-        assert logging_mock.entries[0]["event"] == "testing tracer injection without spans"
-
-        assert logging_mock.entries[1]["event"] == "testing tracer injection without span attributes"
-        assert logging_mock.entries[2]["event"] == "testing tracer injection with span attributes"
-
-        tracing1 = logging_mock.entries[1]["tracing"]
-        tracing2 = logging_mock.entries[2]["tracing"]
-        assert tracing1
-        assert tracing1 == tracing2
+        logger.info("outside span")
+        with get_tracer(__name__).start_as_current_span("test span") as span:
+            context = span.get_span_context()
+            logger.info("inside span")
+
+        outside, inside = [json.loads(line) for line in capsys.readouterr().out.splitlines()]
+        assert outside["event"] == "outside span"
+        assert "tracing" not in outside
+        assert inside["event"] == "inside span"
+        assert inside["tracing"] == {
+            "span_id": format_span_id(context.span_id),
+            "trace_id": format_trace_id(context.trace_id),
+        }
     finally:
         logging_instrument.teardown()
         opentelemetry_instrument.teardown()