Encounter Invalid type <class 'NoneType'> of value None issue.

[DennySORA]

Describe your environment

OS: AWS Ubuntu
telemetry.auto.version: 0.50b0
telemetry.sdk.language: python
telemetry.sdk.name: opentelemetry
telemetry.sdk.version: 1.29.0

What happened?

When I was developing a backend using Python FastAPI, an internal error occurred, throwing an exception. Normally, I should be able to find the error logs in Loki, but for some unknown reason, an OpenTelemetry error was triggered instead, making it impossible for me to trace the application's errors.

My exception should have contained data, but OpenTelemetry displayed it as None, which is very strange. However, even in such cases, it should still be able to display the information correctly. It seems I need to ensure that the body can function properly even if it is None.

Steps to Reproduce

  try:
      1/0
  except Exception as e
      logging.error({"error": None})

Actual Result

{
  "body": "Exception while exporting logs.",
  "severity": "ERROR",
  "attributes": {
    "code.filepath": "/otel-auto-instrumentation-python/opentelemetry/sdk/_logs/_internal/export/__init__.py",
    "code.function": "_export_batch",
    "code.lineno": 313,
    "exception.message": "Invalid type <class 'NoneType'> of value None",
    "exception.stacktrace": "Traceback (most recent call last):\n  File \"/otel-auto-instrumentation-python/opentelemetry/sdk/_logs/_internal/export/__init__.py\", line 311, in _export_batch\n    self._exporter.export(self._log_records[:idx])  # type: ignore\n    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/otel-auto-instrumentation-python/opentelemetry/exporter/otlp/proto/http/_log_exporter/__init__.py\", line 138, in export\n    serialized_data = encode_logs(batch).SerializeToString()\n                      ^^^^^^^^^^^^^^^^^^\n  File \"/otel-auto-instrumentation-python/opentelemetry/exporter/otlp/proto/common/_internal/_log_encoder/__init__.py\", line 38, in encode_logs\n    return ExportLogsServiceRequest(resource_logs=_encode_resource_logs(batch))\n                                                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/otel-auto-instrumentation-python/opentelemetry/exporter/otlp/proto/common/_internal/_log_encoder/__init__.py\", line 62, in _encode_resource_logs\n    pb2_log = _encode_log(sdk_log)\n              ^^^^^^^^^^^^^^^^^^^^\n  File \"/otel-auto-instrumentation-python/opentelemetry/exporter/otlp/proto/common/_internal/_log_encoder/__init__.py\", line 48, in _encode_log\n    body=_encode_value(log_data.log_record.body),\n         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/otel-auto-instrumentation-python/opentelemetry/exporter/otlp/proto/common/_internal/__init__.py\", line 85, in _encode_value\n    values=[_encode_key_value(str(k), v) for k, v in value.items()]\n            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n  File \"/otel-auto-instrumentation-python/opentelemetry/exporter/otlp/proto/common/_internal/__init__.py\", line 92, in _encode_key_value\n    return PB2KeyValue(key=key, value=_encode_value(value))\n                                      ^^^^^^^^^^^^^^^^^^^^\n  File \"/otel-auto-instrumentation-python/opentelemetry/exporter/otlp/proto/common/_internal/__init__.py\", line 88, in _encode_value\n    raise Exception(f\"Invalid type {type(value)} of value {value}\")\nException: Invalid type <class 'NoneType'> of value None\n",
    "exception.type": "Exception",
    "otelServiceName": "aladdin-internal-pii-ai-proxy",
    "otelSpanID": "0",
    "otelTraceID": "0",
    "otelTraceSampled": false
  },
  "resources": {
    "telemetry.auto.version": "0.50b0",
    "telemetry.sdk.language": "python",
    "telemetry.sdk.name": "opentelemetry",
    "telemetry.sdk.version": "1.25.0"
  },
  "instrumentation_scope": {
    "name": "opentelemetry.sdk._logs._internal"
  }
}

Additional context

No response

Would you like to implement a fix?

Yes

[xrmx]

Would be nice to understand what is the value that is None. Does this reproduce with a simpler snippet like below?

    try:
        1/0
    except Exception as e
        log.logger.error({"foo": "bar"})

[DennySORA]

@xrmx
I reproduced the issue with a simpler snippet as shown below.

  try:
      1/0
  except Exception as e
      logging.error({"error": None})

[DennySORA]

This issue happened in the following code:

opentelemetry-python/exporter/opentelemetry-exporter-otlp-proto-common/src/opentelemetry/exporter/otlp/proto/common/_internal/__init__.py

Line 94 in 58f2d16

return PB2KeyValue(key=key, value=_encode_value(value))

Maybe I can update the following to filter out None values and then convert them to another type, such as an empty string:

opentelemetry-python/exporter/opentelemetry-exporter-otlp-proto-common/src/opentelemetry/exporter/otlp/proto/common/_internal/__init__.py

Lines 69 to 90 in 58f2d16

	def _encode_value(value: Any) -> PB2AnyValue:
	if isinstance(value, bool):
	return PB2AnyValue(bool_value=value)
	if isinstance(value, str):
	return PB2AnyValue(string_value=value)
	if isinstance(value, int):
	return PB2AnyValue(int_value=value)
	if isinstance(value, float):
	return PB2AnyValue(double_value=value)
	if isinstance(value, bytes):
	return PB2AnyValue(bytes_value=value)
	if isinstance(value, Sequence):
	return PB2AnyValue(
	array_value=PB2ArrayValue(values=[_encode_value(v) for v in value])
	)
	elif isinstance(value, Mapping):
	return PB2AnyValue(
	kvlist_value=PB2KeyValueList(
	values=[_encode_key_value(str(k), v) for k, v in value.items()]
	)
	)
	raise Exception(f"Invalid type {type(value)} of value {value}")

I found that PB2AnyValue imported from opentelemetry.proto.common.v1.common_pb2 does not have a type of None.

[DennySORA]

I checked the unit test code:

opentelemetry-python/exporter/opentelemetry-exporter-otlp-proto-common/tests/test_attribute_encoder.py

Lines 91 to 93 in 58f2d16

	def test_encode_attributes_error_logs_key(self):
	with self.assertLogs(level=ERROR) as error:
	result = _encode_attributes({"a": 1, "bad_key": None, "b": 2})

Originally, if the dictionary contains a None key, it throws an exception. Should it support None as a value in the future?

[xrmx]

_encode_value is the right place to change, this was already filed as #4279

[DennySORA]

@xrmx OK, Thanks.

[xrmx]

@DennySORA I took a stab at it in #4400