resource-detector-containerid: demote failure to read cgroup files to debug (open-telemetry#3579)

* resource-detector-containerid: demote failure to read cgroup files to debug

Make the detection more quiet so we can load it on application not
running on linux machines without spamming logs.

* Add changelog

Author: xrmx

CHANGELOG.md

@@ -13,6 +13,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Version 1.34.0/0.55b0 (2025-06-04)
 
+### Fixed
+
+- `opentelemetry-resource-detector-containerid`: make it more quiet on platforms without cgroups
+  ([#3579](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3579))
+
 ### Added
 
 - `opentelemetry-instrumentation-aiokafka` Add instrumentation of `consumer.getmany` (batch)

resource/opentelemetry-resource-detector-containerid/src/opentelemetry/resource/detector/containerid/__init__.py

@@ -41,7 +41,7 @@ def _get_container_id_v1():
                     break
 
     except FileNotFoundError as exception:
-        logger.warning("Failed to get container id. Exception: %s", exception)
+        logger.debug("Failed to get container id. Exception: %s", exception)
     return container_id
 
 
@@ -66,7 +66,7 @@ def _get_container_id_v2():
                         break
 
     except FileNotFoundError as exception:
-        logger.warning("Failed to get container id. Exception: %s", exception)
+        logger.debug("Failed to get container id. Exception: %s", exception)
     return container_id
 
 

resource/opentelemetry-resource-detector-containerid/tests/test_container.py

@@ -109,6 +109,48 @@ def test_container_id_detect_from_mountinfo_file(
             actual.attributes.copy(), MockContainerResourceAttributes
         )
 
+    @patch(
+        "opentelemetry.resource.detector.containerid._get_container_id_v1",
+        return_value=None,
+    )
+    @patch(
+        "builtins.open",
+        side_effect=FileNotFoundError,
+    )
+    def test_cannot_read_mountinfo_file(
+        self, mock_get_container_id_v1, mock_mountinfo_file
+    ):
+        with self.assertLogs(
+            "opentelemetry.resource.detector.containerid", level="DEBUG"
+        ) as cm:
+            actual = ContainerResourceDetector().detect()
+        self.assertFalse(actual.attributes.copy())
+        self.assertIn(
+            "DEBUG:opentelemetry.resource.detector.containerid:Failed to get container id. Exception: ",
+            cm.output,
+        )
+
+    @patch(
+        "opentelemetry.resource.detector.containerid._get_container_id_v2",
+        return_value=None,
+    )
+    @patch(
+        "builtins.open",
+        side_effect=FileNotFoundError,
+    )
+    def test_cannot_read_cgroup_file(
+        self, mock_get_container_id_v2, mock_cgroup_file
+    ):
+        with self.assertLogs(
+            "opentelemetry.resource.detector.containerid", level="DEBUG"
+        ) as cm:
+            actual = ContainerResourceDetector().detect()
+        self.assertFalse(actual.attributes.copy())
+        self.assertIn(
+            "DEBUG:opentelemetry.resource.detector.containerid:Failed to get container id. Exception: ",
+            cm.output,
+        )
+
     @patch(
         "opentelemetry.resource.detector.containerid._get_container_id",
         return_value=MockContainerResourceAttributes[