fix(agent-observability): fall back to OTEL_EXPORTER_OTLP_ENDPOINT for unsampled spans (#738)

- When `OTEL_EXPORTER_OTLP_ENDPOINT` is set but
`OTEL_EXPORTER_OTLP_TRACES_ENDPOINT` is not,
`_export_unsampled_span_for_agent_observability` now correctly falls
back to the base endpoint instead of silently skipping

Author: liustve

CHANGELOG.md

@@ -12,6 +12,8 @@ If your change does not need a CHANGELOG entry, add the "skip changelog" label t
 
 ## Unreleased
 
+- fix(agent-observability): fall back to OTEL_EXPORTER_OTLP_ENDPOINT for unsampled spans; also export unsampled spans to non-AWS endpoints
+  ([#738](https://github.com/aws-observability/aws-otel-python-instrumentation/pull/738))
 - feat: auto-detect and mutually exclude AWS native vs third-party agentic instrumentors; add `AWS_AGENTIC_INSTRUMENTATION_OPT_IN` env var to override auto-detection
   ([#729](https://github.com/aws-observability/aws-otel-python-instrumentation/pull/729))
 - fix(lambda-layer): align context propagation with JS — delegate to global propagator so W3C traceparent is no longer ignored when X-Ray active tracing is enabled

aws-opentelemetry-distro/src/amazon/opentelemetry/distro/aws_opentelemetry_configurator.py

@@ -64,6 +64,7 @@
 from opentelemetry.sdk._logs.export import BatchLogRecordProcessor, ConsoleLogRecordExporter, LogRecordExporter
 from opentelemetry.sdk.environment_variables import (
     _OTEL_PYTHON_LOGGING_AUTO_INSTRUMENTATION_ENABLED,
+    OTEL_EXPORTER_OTLP_ENDPOINT,
     OTEL_EXPORTER_OTLP_METRICS_PROTOCOL,
     OTEL_EXPORTER_OTLP_PROTOCOL,
     OTEL_TRACES_SAMPLER_ARG,
@@ -331,11 +332,20 @@ def _export_unsampled_span_for_agent_observability(trace_provider: TracerProvide
         return
 
     traces_endpoint = os.environ.get(OTEL_EXPORTER_OTLP_TRACES_ENDPOINT)
-    if traces_endpoint and _is_aws_otlp_endpoint(traces_endpoint, XRAY_SERVICE):
+    if not traces_endpoint:
+        base_endpoint = os.environ.get(OTEL_EXPORTER_OTLP_ENDPOINT)
+        if base_endpoint:
+            traces_endpoint = base_endpoint.rstrip("/") + "/v1/traces"
+    if not traces_endpoint:
+        return
+
+    if _is_aws_otlp_endpoint(traces_endpoint, XRAY_SERVICE):
         endpoint, region = _extract_endpoint_and_region_from_otlp_endpoint(traces_endpoint)
         span_exporter = _create_aws_otlp_exporter(endpoint=endpoint, service=XRAY_SERVICE, region=region)
+    else:
+        span_exporter = OTLPSpanExporter(endpoint=traces_endpoint)
 
-        trace_provider.add_span_processor(BatchUnsampledSpanProcessor(span_exporter=span_exporter))
+    trace_provider.add_span_processor(BatchUnsampledSpanProcessor(span_exporter=span_exporter))
 
 
 def _is_defer_to_workers_enabled():

aws-opentelemetry-distro/tests/amazon/opentelemetry/distro/test_aws_opentelementry_configurator.py

@@ -1102,6 +1102,43 @@ def test_export_unsampled_span_for_agent_observability(self):
         os.environ.pop("AGENT_OBSERVABILITY_ENABLED", None)
         os.environ.pop("OTEL_EXPORTER_OTLP_TRACES_ENDPOINT", None)
 
+        mock_tracer_provider.reset_mock()
+
+        os.environ["AGENT_OBSERVABILITY_ENABLED"] = "true"
+        os.environ["OTEL_EXPORTER_OTLP_ENDPOINT"] = "http://localhost:4318"
+        _export_unsampled_span_for_agent_observability(mock_tracer_provider, Resource.get_empty())
+        self.assertEqual(mock_tracer_provider.add_span_processor.call_count, 1)
+        processor = mock_tracer_provider.add_span_processor.call_args_list[0].args[0]
+        self.assertIsInstance(processor, BatchUnsampledSpanProcessor)
+        self.assertEqual(processor.span_exporter._endpoint, "http://localhost:4318/v1/traces")
+
+        os.environ.pop("AGENT_OBSERVABILITY_ENABLED", None)
+        os.environ.pop("OTEL_EXPORTER_OTLP_ENDPOINT", None)
+
+        mock_tracer_provider.reset_mock()
+
+        os.environ["AGENT_OBSERVABILITY_ENABLED"] = "true"
+        os.environ["OTEL_EXPORTER_OTLP_ENDPOINT"] = "https://xray.us-west-2.amazonaws.com"
+        _export_unsampled_span_for_agent_observability(mock_tracer_provider, Resource.get_empty())
+        self.assertEqual(mock_tracer_provider.add_span_processor.call_count, 1)
+
+        os.environ.pop("AGENT_OBSERVABILITY_ENABLED", None)
+        os.environ.pop("OTEL_EXPORTER_OTLP_ENDPOINT", None)
+
+        mock_tracer_provider.reset_mock()
+
+        os.environ["AGENT_OBSERVABILITY_ENABLED"] = "true"
+        os.environ["OTEL_EXPORTER_OTLP_TRACES_ENDPOINT"] = "https://xray.us-east-1.amazonaws.com/v1/traces"
+        os.environ["OTEL_EXPORTER_OTLP_ENDPOINT"] = "http://localhost:4318"
+        _export_unsampled_span_for_agent_observability(mock_tracer_provider, Resource.get_empty())
+        self.assertEqual(mock_tracer_provider.add_span_processor.call_count, 1)
+        processor = mock_tracer_provider.add_span_processor.call_args_list[0].args[0]
+        self.assertIsInstance(processor, BatchUnsampledSpanProcessor)
+
+        os.environ.pop("AGENT_OBSERVABILITY_ENABLED", None)
+        os.environ.pop("OTEL_EXPORTER_OTLP_TRACES_ENDPOINT", None)
+        os.environ.pop("OTEL_EXPORTER_OTLP_ENDPOINT", None)
+
     # pylint: disable=no-self-use
     def test_export_unsampled_span_for_agent_observability_uses_aws_exporter(self):
         """Test that OTLPAwsSpanExporter is used for AWS endpoints"""