Implement partial success logging in OTLP exporters

CHANGELOG.md

@@ -12,6 +12,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- OTLP exporters now log partial success responses at `debug` level when `OTEL_LOG_LEVEL` is set to `debug` or `verbose`.
+  ([#4805](https://github.com/open-telemetry/opentelemetry-python/pull/4805))
 - docs: Added sqlcommenter example
   ([#4734](https://github.com/open-telemetry/opentelemetry-python/pull/4734))
 - build: bump ruff to 0.14.1

exporter/opentelemetry-exporter-otlp-proto-grpc/src/opentelemetry/exporter/otlp/proto/grpc/_log_exporter/__init__.py

@@ -11,6 +11,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import sys
 from os import environ
 from typing import Dict, Literal, Optional, Sequence, Tuple, Union
 from typing import Sequence as TypingSequence
@@ -112,6 +113,11 @@ def _translate_data(
     ) -> ExportLogsServiceRequest:
         return encode_logs(data)
 
+    def _log_partial_success(self, partial_success):
+        # Override that skips the "logging" module due to the possibility
+        # of circular logic (logging -> OTLP logs export).
+        sys.stderr.write(f"Partial success:\n{partial_success}\n")
+
     def export(  # type: ignore [reportIncompatibleMethodOverride]
         self,
         batch: Sequence[ReadableLogRecord],

exporter/opentelemetry-exporter-otlp-proto-grpc/src/opentelemetry/exporter/otlp/proto/grpc/exporter.py

@@ -374,6 +374,13 @@ def _translate_data(
     ) -> ExportServiceRequestT:
         pass
 
+    def _log_partial_success(self, partial_success):
+        logger.debug("Partial success:\n%s", partial_success)
+
+    def _process_response(self, response):
+        if response.HasField("partial_success"):
+            self._log_partial_success(response.partial_success)
+
     def _export(
         self,
         data: SDKDataT,
@@ -388,11 +395,12 @@ def _export(
         deadline_sec = time() + self._timeout
         for retry_num in range(_MAX_RETRYS):
             try:
-                self._client.Export(
+                response = self._client.Export(
                     request=self._translate_data(data),
                     metadata=self._headers,
                     timeout=deadline_sec - time(),
                 )
+                self._process_response(response)
                 return self._result.SUCCESS  # type: ignore [reportReturnType]
             except RpcError as error:
                 retry_info_bin = dict(error.trailing_metadata()).get(  # type: ignore [reportAttributeAccessIssue]

exporter/opentelemetry-exporter-otlp-proto-grpc/tests/logs/test_otlp_logs_exporter.py

@@ -15,6 +15,7 @@
 # pylint: disable=too-many-lines
 
 import time
+from io import StringIO
 from os.path import dirname
 from unittest import TestCase
 from unittest.mock import Mock, patch
@@ -28,7 +29,9 @@
     OTLPLogExporter,
 )
 from opentelemetry.proto.collector.logs.v1.logs_service_pb2 import (
+    ExportLogsPartialSuccess,
     ExportLogsServiceRequest,
+    ExportLogsServiceResponse,
 )
 from opentelemetry.proto.common.v1.common_pb2 import AnyValue, KeyValue
 from opentelemetry.proto.common.v1.common_pb2 import (
@@ -316,6 +319,26 @@ def export_log_and_deserialize(self, log_data):
         )
         return log_records
 
+    @patch("sys.stderr", new_callable=StringIO)
+    def test_partial_success_recorded_directly_to_stderr(self, mock_stderr):
+        # pylint: disable=protected-access
+        exporter = OTLPLogExporter()
+        exporter._client = Mock()
+        exporter._client.Export.return_value = ExportLogsServiceResponse(
+            partial_success=ExportLogsPartialSuccess(
+                rejected_log_records=1,
+                error_message="Log record dropped",
+            )
+        )
+
+        exporter.export([self.log_data_1])
+
+        self.assertIn("Partial success:\n", mock_stderr.getvalue())
+        self.assertIn("rejected_log_records: 1\n", mock_stderr.getvalue())
+        self.assertIn(
+            'error_message: "Log record dropped"\n', mock_stderr.getvalue()
+        )
+
     def test_exported_log_without_trace_id(self):
         log_records = self.export_log_and_deserialize(self.log_data_4)
         if log_records:

exporter/opentelemetry-exporter-otlp-proto-grpc/tests/test_otlp_exporter_mixin.py

@@ -40,6 +40,7 @@
 )
 from opentelemetry.exporter.otlp.proto.grpc.version import __version__
 from opentelemetry.proto.collector.trace.v1.trace_service_pb2 import (
+    ExportTracePartialSuccess,
     ExportTraceServiceRequest,
     ExportTraceServiceResponse,
 )
@@ -534,3 +535,22 @@ def test_permanent_failure(self):
                 warning.records[-1].message,
                 "Failed to export traces to localhost:4317, error code: StatusCode.ALREADY_EXISTS",
             )
+
+    @patch("logging.Logger.debug")
+    def test_records_partial_success(self, mock_logger_debug):
+        exporter = OTLPSpanExporterForTesting(insecure=True)
+        # pylint: disable=protected-access
+        exporter._client = Mock()
+        partial_success = ExportTracePartialSuccess(
+            rejected_spans=1,
+            error_message="Span dropped",
+        )
+        exporter._client.Export.return_value = ExportTraceServiceResponse(
+            partial_success=partial_success
+        )
+        exporter.export([self.span])
+
+        mock_logger_debug.assert_called_once_with(
+            "Partial success:\n%s", partial_success
+        )
+        mock_logger_debug.reset_mock()