Add support for user defined attributes in OTLPHandler (open-telemetr…

…y#1952)

CHANGELOG.md

@@ -91,6 +91,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#1893](https://github.com/open-telemetry/opentelemetry-python/pull/1893))
 
 ### Added
+- Give OTLPHandler the ability to process attributes
+  ([#1952](https://github.com/open-telemetry/opentelemetry-python/pull/1952))
 - Add global LogEmitterProvider and convenience function get_log_emitter
   ([#1901](https://github.com/open-telemetry/opentelemetry-python/pull/1901))
 - Add OTLPHandler for standard library logging module

opentelemetry-sdk/src/opentelemetry/sdk/logs/__init__.py

@@ -244,20 +244,59 @@ def force_flush(self, timeout_millis: int = 30000) -> bool:
         return True
 
 
+# skip natural LogRecord attributes
+# http://docs.python.org/library/logging.html#logrecord-attributes
+_RESERVED_ATTRS = frozenset(
+    (
+        "asctime",
+        "args",
+        "created",
+        "exc_info",
+        "exc_text",
+        "filename",
+        "funcName",
+        "getMessage",
+        "levelname",
+        "levelno",
+        "lineno",
+        "module",
+        "msecs",
+        "msg",
+        "name",
+        "pathname",
+        "process",
+        "processName",
+        "relativeCreated",
+        "stack_info",
+        "thread",
+        "threadName",
+    )
+)
+
+
 class OTLPHandler(logging.Handler):
     """A handler class which writes logging records, in OTLP format, to
     a network destination or file.
     """
 
-    def __init__(self, level=logging.NOTSET, log_emitter=None) -> None:
+    def __init__(
+        self,
+        level=logging.NOTSET,
+        log_emitter=None,
+    ) -> None:
         super().__init__(level=level)
         self._log_emitter = log_emitter or get_log_emitter(__name__)
 
+    @staticmethod
+    def _get_attributes(record: logging.LogRecord) -> Attributes:
+        return {
+            k: v for k, v in vars(record).items() if k not in _RESERVED_ATTRS
+        }
+
     def _translate(self, record: logging.LogRecord) -> LogRecord:
         timestamp = int(record.created * 1e9)
         span_context = get_current_span().get_span_context()
-        # TODO: attributes (or resource attributes?) from record metadata
-        attributes: Attributes = {}
+        attributes = self._get_attributes(record)
         severity_number = std_to_otlp(record.levelno)
         return LogRecord(
             timestamp=timestamp,

opentelemetry-sdk/tests/logs/test_handler.py

@@ -65,6 +65,18 @@ def test_log_record_no_span_context(self):
             log_record.trace_flags, INVALID_SPAN_CONTEXT.trace_flags
         )
 
+    def test_log_record_user_attributes(self):
+        """Attributes can be injected into logs by adding them to the LogRecord"""
+        emitter_mock = Mock(spec=LogEmitter)
+        logger = get_logger(log_emitter=emitter_mock)
+        # Assert emit gets called for warning message
+        logger.warning("Warning message", extra={"http.status_code": 200})
+        args, _ = emitter_mock.emit.call_args_list[0]
+        log_record = args[0]
+
+        self.assertIsNotNone(log_record)
+        self.assertEqual(log_record.attributes, {"http.status_code": 200})
+
     def test_log_record_trace_correlation(self):
         emitter_mock = Mock(spec=LogEmitter)
         logger = get_logger(log_emitter=emitter_mock)