fix: map Python CRITICAL log level to OTel FATAL severity text

CHANGELOG.md

@@ -32,6 +32,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#4305](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4305))
 - Don't import module in unwrap if not already imported
   ([#4321](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4321))
+- `opentelemetry-instrumentation-logging`: Map Python `CRITICAL` log level to OTel `FATAL` severity text and `WARNING` to `WARN`
+  ([#4365](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4365))
 - `opentelemetry-instrumentation-logging`: Add recursion guard in LoggingHandler.emit to prevent deadlock
   ([#4302](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4302))
 - `opentelemetry-instrumentation-grpc`: Fix bidirectional streaming RPCs raising `AttributeError: 'generator' object has no attribute 'add_done_callback'`

instrumentation/opentelemetry-instrumentation-logging/src/opentelemetry/instrumentation/logging/handler.py

@@ -188,10 +188,16 @@ def _translate(self, record: logging.LogRecord) -> LogRecord:
             else:
                 body = record.getMessage()
 
-        # related to https://github.com/open-telemetry/opentelemetry-python/issues/3548
-        # Severity Text = WARN as defined in https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/logs/data-model.md#displaying-severity.
-        level_name = (
-            "WARN" if record.levelname == "WARNING" else record.levelname
+        # Map Python log level names to OTel severity text as defined in
+        # https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/logs/data-model.md#displaying-severity
+        # Python "WARNING" -> OTel "WARN" (see open-telemetry/opentelemetry-python#3548)
+        # Python "CRITICAL" -> OTel "FATAL" (see open-telemetry/opentelemetry-python#4984)
+        _python_to_otel_severity_text = {
+            "WARNING": "WARN",
+            "CRITICAL": "FATAL",
+        }
+        level_name = _python_to_otel_severity_text.get(
+            record.levelname, record.levelname
         )
 
         return LogRecord(

instrumentation/opentelemetry-instrumentation-logging/tests/test_handler.py

@@ -357,7 +357,7 @@ def test_log_record_trace_correlation(self):
                     record.log_record.body,
                     "Critical message within span",
                 )
-                self.assertEqual(record.log_record.severity_text, "CRITICAL")
+                self.assertEqual(record.log_record.severity_text, "FATAL")
                 self.assertEqual(
                     record.log_record.severity_number,
                     SeverityNumber.FATAL,
@@ -390,7 +390,7 @@ def test_log_record_trace_correlation_deprecated(self):
             self.assertEqual(
                 record.log_record.body, "Critical message within span"
             )
-            self.assertEqual(record.log_record.severity_text, "CRITICAL")
+            self.assertEqual(record.log_record.severity_text, "FATAL")
             self.assertEqual(
                 record.log_record.severity_number, SeverityNumber.FATAL
             )