opentelemetry-sdk: avoid recursion error with sdk disabled (#4259)

* opentelemetry-sdk: avoid recursion error with sdk disabled

If the sdk is disable and our handler is added to the root logger we
will recurse in order to log that SDK is disabled. Use the
warnings facilities to print the message instead.

* Add changelog

CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Fix metrics export with exemplar and no context and filtering observable instruments
   ([#4251](https://github.com/open-telemetry/opentelemetry-python/pull/4251))
+- Fix recursion error with sdk disabled and handler added to root logger
+  ([#4259](https://github.com/open-telemetry/opentelemetry-python/pull/4259))
 
 ## Version 1.28.0/0.49b0 (2024-11-05)
 

opentelemetry-sdk/src/opentelemetry/sdk/_logs/_internal/__init__.py

@@ -692,7 +692,7 @@ def get_logger(
         attributes: Optional[Attributes] = None,
     ) -> Logger:
         if self._disabled:
-            _logger.warning("SDK is disabled.")
+            warnings.warn("SDK is disabled.")
             return NoOpLogger(
                 name,
                 version=version,

opentelemetry-sdk/tests/logs/test_handler.py

@@ -11,9 +11,12 @@
 # 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 logging
+import os
 import unittest
-from unittest.mock import Mock
+import warnings
+from unittest.mock import Mock, patch
 
 from opentelemetry._logs import NoOpLoggerProvider, SeverityNumber
 from opentelemetry._logs import get_logger as APIGetLogger
@@ -280,12 +283,27 @@ def test_log_body_is_always_string_with_formatter(self):
         log_record = processor.get_log_record(0)
         self.assertIsInstance(log_record.body, str)
 
+    @patch.dict(os.environ, {"OTEL_SDK_DISABLED": "true"})
+    def test_handler_root_logger_with_disabled_sdk_does_not_go_into_recursion_error(
+        self,
+    ):
+        processor, logger = set_up_test_logging(
+            logging.NOTSET, root_logger=True
+        )
+        with warnings.catch_warnings(record=True) as cw:
+            logger.warning("hello")
+
+        self.assertEqual(len(cw), 1)
+        self.assertEqual("SDK is disabled.", str(cw[0].message))
+
+        self.assertEqual(processor.emit_count(), 0)
+
 
-def set_up_test_logging(level, formatter=None):
+def set_up_test_logging(level, formatter=None, root_logger=False):
     logger_provider = LoggerProvider()
     processor = FakeProcessor()
     logger_provider.add_log_record_processor(processor)
-    logger = logging.getLogger("foo")
+    logger = logging.getLogger(None if root_logger else "foo")
     handler = LoggingHandler(level=level, logger_provider=logger_provider)
     if formatter:
         handler.setFormatter(formatter)

opentelemetry-sdk/tests/logs/test_logs.py

@@ -15,6 +15,7 @@
 # pylint: disable=protected-access
 
 import unittest
+import warnings
 from unittest.mock import Mock, patch
 
 from opentelemetry.sdk._logs import LoggerProvider
@@ -69,8 +70,12 @@ def test_get_logger(self):
 
     @patch.dict("os.environ", {OTEL_SDK_DISABLED: "true"})
     def test_get_logger_with_sdk_disabled(self):
-        logger = LoggerProvider().get_logger(Mock())
+        with warnings.catch_warnings(record=True) as cw:
+            logger = LoggerProvider().get_logger(Mock())
+
         self.assertIsInstance(logger, NoOpLogger)
+        self.assertEqual(len(cw), 1)
+        self.assertEqual("SDK is disabled.", str(cw[0].message))
 
     @patch.object(Resource, "create")
     def test_logger_provider_init(self, resource_patch):