Fix cpython.gc metrics to use correct attribute name

- Import CPYTHON_GC_GENERATION from semantic conventions
- Replace "generation" with CPYTHON_GC_GENERATION constant
- Change generation values from strings to integers (0, 1, 2)
- Update tests to use correct attribute name "cpython.gc.generation"

Co-authored-by: xrmx <12932+xrmx@users.noreply.github.com>

Author: Copilot

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

@@ -112,6 +112,9 @@
 from opentelemetry.instrumentation.system_metrics.package import _instruments
 from opentelemetry.instrumentation.system_metrics.version import __version__
 from opentelemetry.metrics import CallbackOptions, Observation, get_meter
+from opentelemetry.semconv._incubating.attributes.cpython_attributes import (
+    CPYTHON_GC_GENERATION,
+)
 from opentelemetry.semconv._incubating.metrics.process_metrics import (
     create_process_cpu_utilization,
 )
@@ -958,7 +961,7 @@ def _get_runtime_gc_collections(
     ) -> Iterable[Observation]:
         """Observer callback for garbage collection"""
         for index, stat in enumerate(gc.get_stats()):
-            self._runtime_gc_collections_labels["generation"] = str(index)
+            self._runtime_gc_collections_labels[CPYTHON_GC_GENERATION] = index
             yield Observation(
                 stat["collections"], self._runtime_gc_collections_labels.copy()
             )
@@ -968,7 +971,7 @@ def _get_runtime_gc_collected_objects(
     ) -> Iterable[Observation]:
         """Observer callback for garbage collection collected objects"""
         for index, stat in enumerate(gc.get_stats()):
-            self._runtime_gc_collected_objects_labels["generation"] = str(
+            self._runtime_gc_collected_objects_labels[CPYTHON_GC_GENERATION] = (
                 index
             )
             yield Observation(
@@ -981,9 +984,9 @@ def _get_runtime_gc_uncollectable_objects(
     ) -> Iterable[Observation]:
         """Observer callback for garbage collection uncollectable objects"""
         for index, stat in enumerate(gc.get_stats()):
-            self._runtime_gc_uncollectable_objects_labels["generation"] = str(
-                index
-            )
+            self._runtime_gc_uncollectable_objects_labels[
+                CPYTHON_GC_GENERATION
+            ] = index
             yield Observation(
                 stat["uncollectable"],
                 self._runtime_gc_uncollectable_objects_labels.copy(),

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

@@ -983,9 +983,9 @@ def test_runtime_get_gc_collections(self, mock_gc_get_stats):
             }
         )
         expected_gc_collections = [
-            _SystemMetricsResult({"generation": "0"}, 10),
-            _SystemMetricsResult({"generation": "1"}, 20),
-            _SystemMetricsResult({"generation": "2"}, 30),
+            _SystemMetricsResult({"cpython.gc.generation": 0}, 10),
+            _SystemMetricsResult({"cpython.gc.generation": 1}, 20),
+            _SystemMetricsResult({"cpython.gc.generation": 2}, 30),
         ]
         self._test_metrics(
             "cpython.gc.collections",
@@ -1007,9 +1007,9 @@ def test_runtime_get_gc_collected_objects(self, mock_gc_get_stats):
             }
         )
         expected_gc_collected_objects = [
-            _SystemMetricsResult({"generation": "0"}, 100),
-            _SystemMetricsResult({"generation": "1"}, 200),
-            _SystemMetricsResult({"generation": "2"}, 300),
+            _SystemMetricsResult({"cpython.gc.generation": 0}, 100),
+            _SystemMetricsResult({"cpython.gc.generation": 1}, 200),
+            _SystemMetricsResult({"cpython.gc.generation": 2}, 300),
         ]
         self._test_metrics(
             "cpython.gc.collected_objects",
@@ -1031,9 +1031,9 @@ def test_runtime_get_gc_uncollectable_objects(self, mock_gc_get_stats):
             }
         )
         expected_gc_uncollectable_objects = [
-            _SystemMetricsResult({"generation": "0"}, 1),
-            _SystemMetricsResult({"generation": "1"}, 2),
-            _SystemMetricsResult({"generation": "2"}, 3),
+            _SystemMetricsResult({"cpython.gc.generation": 0}, 1),
+            _SystemMetricsResult({"cpython.gc.generation": 1}, 2),
+            _SystemMetricsResult({"cpython.gc.generation": 2}, 3),
         ]
         self._test_metrics(
             "cpython.gc.uncollectable_objects",