log the attribute's key when encoding an attribute fails (#3838)

Author: danielhochman

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- When encountering an error encoding metric attributes in the OTLP exporter, log the key that had an error.
+  ([#3838](https://github.com/open-telemetry/opentelemetry-python/pull/3838))
 - Log a warning when a `LogRecord` in `sdk/log` has dropped attributes
   due to reaching limits
   ([#3946](https://github.com/open-telemetry/opentelemetry-python/pull/3946))

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

@@ -110,7 +110,7 @@ def _encode_attributes(
             try:
                 pb2_attributes.append(_encode_key_value(key, value))
             except Exception as error:
-                _logger.exception(error)
+                _logger.exception("Failed to encode key %s: %s", key, error)
     else:
         pb2_attributes = None
     return pb2_attributes

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

@@ -0,0 +1,100 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import unittest
+from logging import ERROR
+
+from opentelemetry.exporter.otlp.proto.common._internal import (
+    _encode_attributes,
+)
+from opentelemetry.proto.common.v1.common_pb2 import AnyValue as PB2AnyValue
+from opentelemetry.proto.common.v1.common_pb2 import (
+    ArrayValue as PB2ArrayValue,
+)
+from opentelemetry.proto.common.v1.common_pb2 import KeyValue as PB2KeyValue
+
+
+class TestOTLPAttributeEncoder(unittest.TestCase):
+    def test_encode_attributes_all_kinds(self):
+        result = _encode_attributes(
+            {
+                "a": 1,  # int
+                "b": 3.14,  # float
+                "c": False,  # bool
+                "hello": "world",  # str
+                "greet": ["hola", "bonjour"],  # Sequence[str]
+                "data": [1, 2],  # Sequence[int]
+                "data_granular": [1.4, 2.4],  # Sequence[float]
+            }
+        )
+        self.assertEqual(
+            result,
+            [
+                PB2KeyValue(key="a", value=PB2AnyValue(int_value=1)),
+                PB2KeyValue(key="b", value=PB2AnyValue(double_value=3.14)),
+                PB2KeyValue(key="c", value=PB2AnyValue(bool_value=False)),
+                PB2KeyValue(
+                    key="hello", value=PB2AnyValue(string_value="world")
+                ),
+                PB2KeyValue(
+                    key="greet",
+                    value=PB2AnyValue(
+                        array_value=PB2ArrayValue(
+                            values=[
+                                PB2AnyValue(string_value="hola"),
+                                PB2AnyValue(string_value="bonjour"),
+                            ]
+                        )
+                    ),
+                ),
+                PB2KeyValue(
+                    key="data",
+                    value=PB2AnyValue(
+                        array_value=PB2ArrayValue(
+                            values=[
+                                PB2AnyValue(int_value=1),
+                                PB2AnyValue(int_value=2),
+                            ]
+                        )
+                    ),
+                ),
+                PB2KeyValue(
+                    key="data_granular",
+                    value=PB2AnyValue(
+                        array_value=PB2ArrayValue(
+                            values=[
+                                PB2AnyValue(double_value=1.4),
+                                PB2AnyValue(double_value=2.4),
+                            ]
+                        )
+                    ),
+                ),
+            ],
+        )
+
+    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})
+
+        self.assertEqual(len(error.records), 1)
+        self.assertEqual(error.records[0].msg, "Failed to encode key %s: %s")
+        self.assertEqual(error.records[0].args[0], "bad_key")
+        self.assertIsInstance(error.records[0].args[1], Exception)
+        self.assertEqual(
+            result,
+            [
+                PB2KeyValue(key="a", value=PB2AnyValue(int_value=1)),
+                PB2KeyValue(key="b", value=PB2AnyValue(int_value=2)),
+            ],
+        )