Make create_gauge non-abstract method

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- Make create_gauge non-abstract method
+  ([#3817](https://github.com/open-telemetry/opentelemetry-python/pull/3817))
 - Make `tracer.start_as_current_span()` decorator work with async functions
   ([#3633](https://github.com/open-telemetry/opentelemetry-python/pull/3633))
 - Fix python 3.12 deprecation warning

opentelemetry-api/src/opentelemetry/metrics/_internal/__init__.py

@@ -41,6 +41,7 @@
 """
 
 
+import warnings
 from abc import ABC, abstractmethod
 from logging import getLogger
 from os import environ
@@ -385,8 +386,7 @@ def create_histogram(
             description: A description for this instrument and what it measures.
         """
 
-    @abstractmethod
-    def create_gauge(
+    def create_gauge(  # type: ignore # pylint: disable=no-self-use
         self,
         name: str,
         unit: str = "",
@@ -400,6 +400,7 @@ def create_gauge(
                 example, ``By`` for bytes. UCUM units are recommended.
             description: A description for this instrument and what it measures.
         """
+        warnings.warn("create_gauge() is not implemented and will be a no-op")
 
     @abstractmethod
     def create_observable_gauge(

opentelemetry-api/tests/metrics/test_meter.py

@@ -134,7 +134,6 @@ def test_create_gauge(self):
         """
 
         self.assertTrue(hasattr(Meter, "create_gauge"))
-        self.assertTrue(Meter.create_gauge.__isabstractmethod__)
 
     def test_create_observable_gauge(self):
         """

opentelemetry-api/tests/metrics/test_subclass_instantiation.py

@@ -0,0 +1,209 @@
+# Copyright The OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# 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.
+# type: ignore
+
+# NOTE: The tests in this file are intended to test the semver compatibility of the public API.
+# Any tests that fail here indicate that the public API has changed in a way that is not backwards compatible.
+# Either bump the major version of the API, or make the necessary changes to the API to remain semver compatible.
+
+from typing import Optional
+
+from opentelemetry.metrics import (
+    Asynchronous,
+    Counter,
+    Histogram,
+    Instrument,
+    Meter,
+    MeterProvider,
+    ObservableCounter,
+    ObservableGauge,
+    ObservableUpDownCounter,
+    Synchronous,
+    UpDownCounter,
+    _Gauge,
+)
+
+
+class MeterProviderImplTest(MeterProvider):
+    def get_meter(
+        self,
+        name: str,
+        version: Optional[str] = None,
+        schema_url: Optional[str] = None,
+    ) -> Meter:
+        return super().get_meter(name, version, schema_url)
+
+
+def test_meter_provider_subclass_instantiation():
+    meter_provider = MeterProviderImplTest()
+    assert isinstance(meter_provider, MeterProvider)
+
+
+class MeterImplTest(Meter):
+    def create_counter(self, name, description, **kwargs):
+        pass
+
+    def create_up_down_counter(self, name, description, **kwargs):
+        pass
+
+    def create_observable_counter(self, name, description, **kwargs):
+        pass
+
+    def create_histogram(self, name, description, **kwargs):
+        pass
+
+    def create_observable_gauge(self, name, description, **kwargs):
+        pass
+
+    def create_observable_up_down_counter(self, name, description, **kwargs):
+        pass
+
+
+def test_meter_subclass_instantiation():
+    meter = MeterImplTest("subclass_test")
+    assert isinstance(meter, Meter)
+
+
+class SynchronousImplTest(Synchronous):
+    def __init__(
+        self, name: str, unit: str = "", description: str = ""
+    ) -> None:
+        super().__init__(name, unit, description)
+
+
+def test_synchronous_subclass_instantiation():
+    synchronous = SynchronousImplTest("subclass_test")
+    assert isinstance(synchronous, Synchronous)
+
+
+class AsynchronousImplTest(Asynchronous):
+    def __init__(
+        self, name: str, unit: str = "", description: str = ""
+    ) -> None:
+        super().__init__(name, unit, description)
+
+
+def test_asynchronous_subclass_instantiation():
+    asynchronous = AsynchronousImplTest("subclass_test")
+    assert isinstance(asynchronous, Asynchronous)
+
+
+class CounterImplTest(Counter):
+    def __init__(
+        self, name: str, unit: str = "", description: str = ""
+    ) -> None:
+        super().__init__(name, unit, description)
+
+    def add(self, amount: int, **kwargs):
+        pass
+
+
+def test_counter_subclass_instantiation():
+    counter = CounterImplTest("subclass_test")
+    assert isinstance(counter, Counter)
+
+
+class UpDownCounterImplTest(UpDownCounter):
+    def __init__(
+        self, name: str, unit: str = "", description: str = ""
+    ) -> None:
+        super().__init__(name, unit, description)
+
+    def add(self, amount: int, **kwargs):
+        pass
+
+
+def test_up_down_counter_subclass_instantiation():
+    up_down_counter = UpDownCounterImplTest("subclass_test")
+    assert isinstance(up_down_counter, UpDownCounter)
+
+
+class ObservableCounterImplTest(ObservableCounter):
+    def __init__(
+        self, name: str, unit: str = "", description: str = ""
+    ) -> None:
+        super().__init__(name, unit, description)
+
+
+def test_observable_counter_subclass_instantiation():
+    observable_counter = ObservableCounterImplTest("subclass_test")
+    assert isinstance(observable_counter, ObservableCounter)
+
+
+class HistogramImplTest(Histogram):
+    def __init__(
+        self, name: str, unit: str = "", description: str = ""
+    ) -> None:
+        super().__init__(name, unit, description)
+
+    def record(self, amount: int, **kwargs):
+        pass
+
+
+def test_histogram_subclass_instantiation():
+    histogram = HistogramImplTest("subclass_test")
+    assert isinstance(histogram, Histogram)
+
+
+class GaugeImplTest(_Gauge):
+    def __init__(
+        self, name: str, unit: str = "", description: str = ""
+    ) -> None:
+        super().__init__(name, unit, description)
+
+    def set(self, amount: int, **kwargs):
+        pass
+
+
+def test_gauge_subclass_instantiation():
+    gauge = GaugeImplTest("subclass_test")
+    assert isinstance(gauge, _Gauge)
+
+
+class InstrumentImplTest(Instrument):
+    def __init__(
+        self, name: str, unit: str = "", description: str = ""
+    ) -> None:
+        super().__init__(name, unit, description)
+
+
+def test_instrument_subclass_instantiation():
+    instrument = InstrumentImplTest("subclass_test")
+    assert isinstance(instrument, Instrument)
+
+
+class ObservableGaugeImplTest(ObservableGauge):
+    def __init__(
+        self, name: str, unit: str = "", description: str = ""
+    ) -> None:
+        super().__init__(name, unit, description)
+
+
+def test_observable_gauge_subclass_instantiation():
+    observable_gauge = ObservableGaugeImplTest("subclass_test")
+    assert isinstance(observable_gauge, ObservableGauge)
+
+
+class ObservableUpDownCounterImplTest(ObservableUpDownCounter):
+    def __init__(
+        self, name: str, unit: str = "", description: str = ""
+    ) -> None:
+        super().__init__(name, unit, description)
+
+
+def test_observable_up_down_counter_subclass_instantiation():
+    observable_up_down_counter = ObservableUpDownCounterImplTest(
+        "subclass_test"
+    )
+    assert isinstance(observable_up_down_counter, ObservableUpDownCounter)