fix: exception log message format (#394)

google/cloud/logging_v2/handlers/structured_log.py

@@ -62,9 +62,14 @@ def format(self, record):
         # let other formatters alter the message
         super_payload = None
         if record.msg:
+            # format the message using default handler behaviors
             super_payload = super(StructuredLogHandler, self).format(record)
         # properly break any formatting in string to make it json safe
         record._formatted_msg = json.dumps(super_payload or "")
+        # remove exception info to avoid duplicating it
+        # https://github.com/googleapis/python-logging/issues/382
+        record.exc_info = None
+        record.exc_text = None
         # convert to GCP structred logging format
         gcp_payload = self._gcp_formatter.format(record)
         return gcp_payload

tests/unit/handlers/test_structured_log.py

@@ -119,6 +119,24 @@ def test_format_with_quotes(self):
         result = handler.format(record)
         self.assertIn(expected_result, result)
 
+    def test_format_with_exception(self):
+        """
+        When logging a message with an exception, the stack trace should not be appended
+        """
+        import logging
+        import json
+
+        handler = self._make_one()
+        exception_tuple = (Exception, Exception(), None)
+        message = "test"
+        record = logging.LogRecord(
+            None, logging.INFO, None, None, message, None, exception_tuple
+        )
+        record.created = None
+        handler.filter(record)
+        result = json.loads(handler.format(record))
+        self.assertEqual(result["message"], f"{message}\nException")
+
     def test_format_with_line_break(self):
         """
         When logging a message containing \n, it should be properly escaped