semconv: use X | Y union annotation

CHANGELOG.md

@@ -22,6 +22,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#4907](https://github.com/open-telemetry/opentelemetry-python/issues/4907))
 - Drop Python 3.9 support
   ([#5076](https://github.com/open-telemetry/opentelemetry-python/pull/5076))
+- `opentelemetry-semantic-conventions`: use `X | Y` union annotation
+  ([#5096](https://github.com/open-telemetry/opentelemetry-python/pull/5096))
 
 
 ## Version 1.41.0/0.62b0 (2026-04-09)

opentelemetry-semantic-conventions/src/opentelemetry/semconv/_incubating/metrics/container_metrics.py

@@ -13,15 +13,8 @@
 # limitations under the License.
 
 
-from typing import (
-    Callable,
-    Final,
-    Generator,
-    Iterable,
-    Optional,
-    Sequence,
-    Union,
-)
+from collections.abc import Callable, Generator, Iterable, Sequence
+from typing import Final
 
 from opentelemetry.metrics import (
     CallbackOptions,
@@ -33,10 +26,10 @@
 )
 
 # pylint: disable=invalid-name
-CallbackT = Union[
-    Callable[[CallbackOptions], Iterable[Observation]],
-    Generator[Iterable[Observation], CallbackOptions, None],
-]
+CallbackT = (
+    Callable[[CallbackOptions], Iterable[Observation]]
+    | Generator[Iterable[Observation], CallbackOptions, None]
+)
 
 CONTAINER_CPU_TIME: Final = "container.cpu.time"
 """
@@ -66,7 +59,7 @@ def create_container_cpu_time(meter: Meter) -> Counter:
 
 
 def create_container_cpu_usage(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Container's CPU usage, measured in cpus. Range from 0 to the number of allocatable CPUs"""
     return meter.create_observable_gauge(
@@ -284,7 +277,7 @@ def create_container_network_io(meter: Meter) -> Counter:
 
 
 def create_container_uptime(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """The time the container has been running"""
     return meter.create_observable_gauge(

opentelemetry-semantic-conventions/src/opentelemetry/semconv/_incubating/metrics/cpu_metrics.py

@@ -13,15 +13,8 @@
 # limitations under the License.
 
 
-from typing import (
-    Callable,
-    Final,
-    Generator,
-    Iterable,
-    Optional,
-    Sequence,
-    Union,
-)
+from collections.abc import Callable, Generator, Iterable, Sequence
+from typing import Final
 
 from opentelemetry.metrics import (
     CallbackOptions,
@@ -32,10 +25,10 @@
 )
 
 # pylint: disable=invalid-name
-CallbackT = Union[
-    Callable[[CallbackOptions], Iterable[Observation]],
-    Generator[Iterable[Observation], CallbackOptions, None],
-]
+CallbackT = (
+    Callable[[CallbackOptions], Iterable[Observation]]
+    | Generator[Iterable[Observation], CallbackOptions, None]
+)
 
 CPU_FREQUENCY: Final = "cpu.frequency"
 """
@@ -44,7 +37,7 @@
 
 
 def create_cpu_frequency(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Deprecated. Use `system.cpu.frequency` instead"""
     return meter.create_observable_gauge(
@@ -77,7 +70,7 @@ def create_cpu_time(meter: Meter) -> Counter:
 
 
 def create_cpu_utilization(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Deprecated. Use `system.cpu.utilization` instead"""
     return meter.create_observable_gauge(

opentelemetry-semantic-conventions/src/opentelemetry/semconv/_incubating/metrics/hw_metrics.py

@@ -13,15 +13,8 @@
 # limitations under the License.
 
 
-from typing import (
-    Callable,
-    Final,
-    Generator,
-    Iterable,
-    Optional,
-    Sequence,
-    Union,
-)
+from collections.abc import Callable, Generator, Iterable, Sequence
+from typing import Final
 
 from opentelemetry.metrics import (
     CallbackOptions,
@@ -33,10 +26,10 @@
 )
 
 # pylint: disable=invalid-name
-CallbackT = Union[
-    Callable[[CallbackOptions], Iterable[Observation]],
-    Generator[Iterable[Observation], CallbackOptions, None],
-]
+CallbackT = (
+    Callable[[CallbackOptions], Iterable[Observation]]
+    | Generator[Iterable[Observation], CallbackOptions, None]
+)
 
 HW_BATTERY_CHARGE: Final = "hw.battery.charge"
 """
@@ -47,7 +40,7 @@
 
 
 def create_hw_battery_charge(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Remaining fraction of battery charge"""
     return meter.create_observable_gauge(
@@ -67,7 +60,7 @@ def create_hw_battery_charge(
 
 
 def create_hw_battery_charge_limit(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Lower limit of battery charge fraction to ensure proper operation"""
     return meter.create_observable_gauge(
@@ -87,7 +80,7 @@ def create_hw_battery_charge_limit(
 
 
 def create_hw_battery_time_left(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Time left before battery is completely charged or discharged"""
     return meter.create_observable_gauge(
@@ -107,7 +100,7 @@ def create_hw_battery_time_left(
 
 
 def create_hw_cpu_speed(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """CPU current frequency"""
     return meter.create_observable_gauge(
@@ -127,7 +120,7 @@ def create_hw_cpu_speed(
 
 
 def create_hw_cpu_speed_limit(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """CPU maximum frequency"""
     return meter.create_observable_gauge(
@@ -181,7 +174,7 @@ def create_hw_errors(meter: Meter) -> Counter:
 
 
 def create_hw_fan_speed(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Fan speed in revolutions per minute"""
     return meter.create_observable_gauge(
@@ -201,7 +194,7 @@ def create_hw_fan_speed(
 
 
 def create_hw_fan_speed_limit(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Speed limit in rpm"""
     return meter.create_observable_gauge(
@@ -221,7 +214,7 @@ def create_hw_fan_speed_limit(
 
 
 def create_hw_fan_speed_ratio(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Fan speed expressed as a fraction of its maximum speed"""
     return meter.create_observable_gauge(
@@ -292,7 +285,7 @@ def create_hw_gpu_memory_usage(meter: Meter) -> UpDownCounter:
 
 
 def create_hw_gpu_memory_utilization(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Fraction of GPU memory used"""
     return meter.create_observable_gauge(
@@ -312,7 +305,7 @@ def create_hw_gpu_memory_utilization(
 
 
 def create_hw_gpu_utilization(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Fraction of time spent in a specific task"""
     return meter.create_observable_gauge(
@@ -332,7 +325,7 @@ def create_hw_gpu_utilization(
 
 
 def create_hw_host_ambient_temperature(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Ambient (external) temperature of the physical host"""
     return meter.create_observable_gauge(
@@ -370,7 +363,7 @@ def create_hw_host_energy(meter: Meter) -> Counter:
 
 
 def create_hw_host_heating_margin(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """By how many degrees Celsius the temperature of the physical host can be increased, before reaching a warning threshold on one of the internal sensors"""
     return meter.create_observable_gauge(
@@ -391,7 +384,7 @@ def create_hw_host_heating_margin(
 
 
 def create_hw_host_power(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Instantaneous power consumed by the entire physical host in Watts (`hw.host.energy` is preferred)"""
     return meter.create_observable_gauge(
@@ -445,7 +438,7 @@ def create_hw_logical_disk_usage(meter: Meter) -> UpDownCounter:
 
 
 def create_hw_logical_disk_utilization(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Logical disk space utilization as a fraction"""
     return meter.create_observable_gauge(
@@ -499,7 +492,7 @@ def create_hw_network_bandwidth_limit(meter: Meter) -> UpDownCounter:
 
 
 def create_hw_network_bandwidth_utilization(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Utilization of the network bandwidth as a fraction"""
     return meter.create_observable_gauge(
@@ -572,7 +565,7 @@ def create_hw_network_up(meter: Meter) -> UpDownCounter:
 
 
 def create_hw_physical_disk_endurance_utilization(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Endurance remaining for this SSD disk"""
     return meter.create_observable_gauge(
@@ -609,7 +602,7 @@ def create_hw_physical_disk_size(meter: Meter) -> UpDownCounter:
 
 
 def create_hw_physical_disk_smart(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Value of the corresponding [S.M.A.R.T.](https://wikipedia.org/wiki/S.M.A.R.T.) (Self-Monitoring, Analysis, and Reporting Technology) attribute"""
     return meter.create_observable_gauge(
@@ -630,7 +623,7 @@ def create_hw_physical_disk_smart(
 
 
 def create_hw_power(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Instantaneous power consumed by the component"""
     return meter.create_observable_gauge(
@@ -684,7 +677,7 @@ def create_hw_power_supply_usage(meter: Meter) -> UpDownCounter:
 
 
 def create_hw_power_supply_utilization(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Utilization of the power supply as a fraction of its maximum output"""
     return meter.create_observable_gauge(
@@ -739,7 +732,7 @@ def create_hw_tape_drive_operations(meter: Meter) -> Counter:
 
 
 def create_hw_temperature(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Temperature in degrees Celsius"""
     return meter.create_observable_gauge(
@@ -759,7 +752,7 @@ def create_hw_temperature(
 
 
 def create_hw_temperature_limit(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Temperature limit in degrees Celsius"""
     return meter.create_observable_gauge(
@@ -779,7 +772,7 @@ def create_hw_temperature_limit(
 
 
 def create_hw_voltage(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Voltage measured by the sensor"""
     return meter.create_observable_gauge(
@@ -799,7 +792,7 @@ def create_hw_voltage(
 
 
 def create_hw_voltage_limit(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Voltage limit in Volts"""
     return meter.create_observable_gauge(
@@ -819,7 +812,7 @@ def create_hw_voltage_limit(
 
 
 def create_hw_voltage_nominal(
-    meter: Meter, callbacks: Optional[Sequence[CallbackT]]
+    meter: Meter, callbacks: Sequence[CallbackT] | None
 ) -> ObservableGauge:
     """Nominal (expected) voltage"""
     return meter.create_observable_gauge(