opentelemetry-instrumentation-system-metrics: don't report files descriptors on windows

Author: xrmx

CHANGELOG.md

@@ -38,6 +38,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#2940](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2940))
 - `opentelemetry-instrumentation-dbapi` sqlcommenter key values created from PostgreSQL, MySQL systems
   ([#2897](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2897))
+- `opentelemetry-instrumentation-system-metrics`: don't report open file descriptors on Windows
+  ([#2946](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/2946))
 
 ### Breaking changes
 

instrumentation/opentelemetry-instrumentation-system-metrics/src/opentelemetry/instrumentation/system_metrics/__init__.py

@@ -397,7 +397,10 @@ def _instrument(self, **kwargs):
                 unit="switches",
             )
 
-        if "process.open_file_descriptor.count" in self._config:
+        if (
+            sys.platform != "win32"
+            and "process.open_file_descriptor.count" in self._config
+        ):
             self._meter.create_observable_up_down_counter(
                 name="process.open_file_descriptor.count",
                 callbacks=[self._get_open_file_descriptors],

instrumentation/opentelemetry-instrumentation-system-metrics/tests/test_system_metrics.py

@@ -14,6 +14,7 @@
 
 # pylint: disable=protected-access
 
+import sys
 from collections import namedtuple
 from platform import python_implementation
 from unittest import mock, skipIf
@@ -118,21 +119,30 @@ def test_system_metrics_instrument(self):
             f"process.runtime.{self.implementation}.thread_count",
             f"process.runtime.{self.implementation}.context_switches",
             f"process.runtime.{self.implementation}.cpu.utilization",
-            "process.open_file_descriptor.count",
         ]
 
+        on_windows = sys.platform == "win32"
         if self.implementation == "pypy":
-            self.assertEqual(len(metric_names), 21)
+            self.assertEqual(len(metric_names), 20 if on_windows else 21)
         else:
-            self.assertEqual(len(metric_names), 22)
+            self.assertEqual(len(metric_names), 21 if on_windows else 22)
         observer_names.append(
             f"process.runtime.{self.implementation}.gc_count",
         )
+        if not on_windows:
+            observer_names.append(
+                "process.open_file_descriptor.count",
+            )
 
         for observer in metric_names:
             self.assertIn(observer, observer_names)
             observer_names.remove(observer)
 
+        if on_windows:
+            self.assertNotIn(
+                "process.open_file_descriptor.count", observer_names
+            )
+
     def test_runtime_metrics_instrument(self):
         runtime_config = {
             "process.runtime.memory": ["rss", "vms"],