fix(exporter/otlp/http): log error details from response on export failure

CHANGELOG.md

@@ -12,6 +12,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- `opentelemetry-exporter-otlp-proto-http`: Log server error details from response body on export failure
+  ([#5155](https://github.com/open-telemetry/opentelemetry-python/pull/5155))
 - `opentelemetry-sdk`: fix multi-processor `force_flush` skipping remaining processors when one returns `None`
   ([#5179](https://github.com/open-telemetry/opentelemetry-python/pull/5179))
 - Apply fixes for `UP` ruff rule

exporter/opentelemetry-exporter-otlp-proto-http/src/opentelemetry/exporter/otlp/proto/http/_common/__init__.py

@@ -1,16 +1,73 @@
 # Copyright The OpenTelemetry Authors
 # SPDX-License-Identifier: Apache-2.0
 
+import logging
 from os import environ
 from typing import Literal
 
 import requests
+from google.rpc.status_pb2 import Status
 
 from opentelemetry.sdk.environment_variables import (
     _OTEL_PYTHON_EXPORTER_OTLP_HTTP_CREDENTIAL_PROVIDER,
 )
 from opentelemetry.util._importlib_metadata import entry_points
 
+_logger = logging.getLogger(__name__)
+
+_CONTENT_TYPE_PROTOBUF = "application/x-protobuf"
+_CONTENT_TYPE_JSON = "application/json"
+
+
+def _parse_response_body(resp: requests.Response) -> str:
+    """Parse an HTTP response body based on its Content-Type header.
+
+    Per the OTLP spec, error responses (4xx/5xx) use ``google.rpc.Status``
+    for protobuf bodies and the equivalent JSON representation.
+
+    Args:
+        resp: The HTTP response from the OTLP endpoint.
+
+    Returns:
+        A human-readable string describing the response body error details,
+        or ``resp.reason`` if the body is empty or cannot be parsed.
+    """
+    if not resp.content:
+        return resp.reason
+
+    content_type = (
+        resp.headers.get("Content-Type", "").split(";", 1)[0].strip().lower()
+    )
+
+    if content_type == _CONTENT_TYPE_PROTOBUF:
+        status = Status()
+        try:
+            status.ParseFromString(resp.content)
+        except Exception:  # pylint: disable=broad-except
+            _logger.debug(
+                "Failed to parse protobuf response body", exc_info=True
+            )
+            return resp.reason
+        return status.message or resp.reason
+
+    if content_type == _CONTENT_TYPE_JSON:
+        try:
+            body = resp.json()
+        except Exception:  # pylint: disable=broad-except
+            _logger.debug("Failed to parse JSON response body", exc_info=True)
+            return resp.text or resp.reason
+        if isinstance(body, dict):
+            partial = body.get("partialSuccess")
+            if isinstance(partial, dict) and (
+                error_message := partial.get("errorMessage", "")
+            ):
+                return error_message
+            # google.rpc.Status uses "message"
+            if rpc_message := body.get("message", ""):
+                return rpc_message
+
+    return resp.text.strip() or resp.reason
+
 
 def _is_retryable(resp: requests.Response) -> bool:
     if resp.status_code == 408:

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

@@ -27,6 +27,7 @@
 from opentelemetry.exporter.otlp.proto.http._common import (
     _is_retryable,
     _load_session_from_envvar,
+    _parse_response_body,
 )
 from opentelemetry.metrics import MeterProvider
 from opentelemetry.sdk._logs import ReadableLogRecord
@@ -215,7 +216,7 @@ def export(
                     retryable = isinstance(error, ConnectionError)
                     status_code = None
                 else:
-                    reason = resp.reason
+                    reason = _parse_response_body(resp)
                     retryable = _is_retryable(resp)
                     status_code = resp.status_code
 

exporter/opentelemetry-exporter-otlp-proto-http/src/opentelemetry/exporter/otlp/proto/http/metric_exporter/__init__.py

@@ -41,10 +41,12 @@
 from opentelemetry.exporter.otlp.proto.http._common import (
     _is_retryable,
     _load_session_from_envvar,
+    _parse_response_body,
 )
 from opentelemetry.metrics import MeterProvider
 from opentelemetry.proto.collector.metrics.v1.metrics_service_pb2 import (  # noqa: F401
     ExportMetricsServiceRequest,
+    ExportMetricsServiceResponse,
 )
 from opentelemetry.proto.common.v1.common_pb2 import (  # noqa: F401
     AnyValue,
@@ -286,7 +288,7 @@ def _export_with_retries(
                     retryable = isinstance(error, ConnectionError)
                     status_code = None
                 else:
-                    reason = resp.reason
+                    reason = _parse_response_body(resp)
                     retryable = _is_retryable(resp)
                     status_code = resp.status_code
 

exporter/opentelemetry-exporter-otlp-proto-http/src/opentelemetry/exporter/otlp/proto/http/trace_exporter/__init__.py

@@ -29,6 +29,7 @@
 from opentelemetry.exporter.otlp.proto.http._common import (
     _is_retryable,
     _load_session_from_envvar,
+    _parse_response_body,
 )
 from opentelemetry.metrics import MeterProvider
 from opentelemetry.sdk.environment_variables import (
@@ -208,7 +209,7 @@ def export(self, spans: Sequence[ReadableSpan]) -> SpanExportResult:
                     retryable = isinstance(error, ConnectionError)
                     status_code = None
                 else:
-                    reason = resp.reason
+                    reason = _parse_response_body(resp)
                     retryable = _is_retryable(resp)
                     status_code = resp.status_code
 

exporter/opentelemetry-exporter-otlp-proto-http/tests/test_proto_log_exporter.py

@@ -3,6 +3,7 @@
 
 # pylint: disable=protected-access
 
+import logging
 import threading
 import time
 import unittest
@@ -11,6 +12,7 @@
 
 import requests
 from google.protobuf.json_format import MessageToDict
+from google.rpc.status_pb2 import Status
 from requests import Session
 from requests.exceptions import ConnectionError
 from requests.models import Response
@@ -74,6 +76,11 @@ def setUp(self):
         self.meter_provider = MeterProvider(
             metric_readers=[self.metric_reader]
         )
+        # Reset DuplicateFilter state between tests so each test can log freely.
+        log_exporter_logger = logging.getLogger(
+            "opentelemetry.exporter.otlp.proto.http._log_exporter"
+        )
+        log_exporter_logger.filters.clear()
 
     def test_constructor_default(self):
         exporter = OTLPLogExporter()
@@ -656,6 +663,25 @@ def test_shutdown_interrupts_retry_backoff(self, mock_post):
 
             assert after - before < 0.2
 
+    @patch.object(Session, "post")
+    def test_error_response_with_protobuf_body(self, mock_post):
+        status = Status(code=3, message="invalid log data")
+        resp = Response()
+        resp.status_code = 400
+        resp.reason = "Bad Request"
+        resp._content = status.SerializeToString()  # pylint: disable=protected-access
+        resp.headers["Content-Type"] = "application/x-protobuf"
+        mock_post.return_value = resp
+
+        exporter = OTLPLogExporter()
+        with self.assertLogs(level="ERROR") as logs:
+            result = exporter.export(self._get_sdk_log_data())
+
+        self.assertEqual(result, LogRecordExportResult.FAILURE)
+        self.assertTrue(
+            any("invalid log data" in r.message for r in logs.records)
+        )
+
     def assert_standard_metric_attrs(self, attributes):
         self.assertEqual(
             attributes["otel.component.type"], "otlp_http_log_exporter"

exporter/opentelemetry-exporter-otlp-proto-http/tests/test_proto_span_exporter.py

@@ -1,13 +1,15 @@
 # Copyright The OpenTelemetry Authors
 # SPDX-License-Identifier: Apache-2.0
 
+import json
 import threading
 import time
 import unittest
 from logging import WARNING
 from unittest.mock import MagicMock, Mock, patch
 
 import requests
+from google.rpc.status_pb2 import Status
 from requests import Session
 from requests.exceptions import ConnectionError
 from requests.models import Response
@@ -486,6 +488,44 @@ def test_shutdown_interrupts_retry_backoff(self, mock_post):
 
             assert after - before < 0.2
 
+    @patch.object(Session, "post")
+    def test_error_response_with_protobuf_body(self, mock_post):
+        status = Status(code=3, message="invalid span data")
+        resp = Response()
+        resp.status_code = 400
+        resp.reason = "Bad Request"
+        resp._content = status.SerializeToString()  # pylint: disable=protected-access
+        resp.headers["Content-Type"] = "application/x-protobuf"
+        mock_post.return_value = resp
+
+        exporter = OTLPSpanExporter()
+        with self.assertLogs(level="ERROR") as logs:
+            result = exporter.export([BASIC_SPAN])
+
+        self.assertEqual(result, SpanExportResult.FAILURE)
+        self.assertTrue(
+            any("invalid span data" in r.message for r in logs.records)
+        )
+
+    @patch.object(Session, "post")
+    def test_error_response_with_json_body(self, mock_post):
+        body = json.dumps({"message": "quota limit reached"}).encode()
+        resp = Response()
+        resp.status_code = 400
+        resp.reason = "Bad Request"
+        resp._content = body  # pylint: disable=protected-access
+        resp.headers["Content-Type"] = "application/json"
+        mock_post.return_value = resp
+
+        exporter = OTLPSpanExporter()
+        with self.assertLogs(level="ERROR") as logs:
+            result = exporter.export([BASIC_SPAN])
+
+        self.assertEqual(result, SpanExportResult.FAILURE)
+        self.assertTrue(
+            any("quota limit reached" in r.message for r in logs.records)
+        )
+
     def assert_standard_metric_attrs(self, attributes):
         self.assertEqual(
             attributes["otel.component.type"], "otlp_http_span_exporter"