Add autoinstrumentation entrypoint for monitoring exporter (#275)

opentelemetry-exporter-gcp-monitoring/setup.cfg

@@ -36,3 +36,9 @@ where = src
 
 [options.extras_require]
 test =
+
+[options.entry_points]
+opentelemetry_metrics_exporter =
+    gcp_monitoring = opentelemetry.exporter.cloud_monitoring:CloudMonitoringMetricsExporter
+opentelemetry_environment_variables =
+    gcp_monitoring = opentelemetry.exporter.cloud_monitoring.environment_variables

opentelemetry-exporter-gcp-monitoring/src/opentelemetry/exporter/cloud_monitoring/environment_variables.py

@@ -0,0 +1,23 @@
+# Copyright 2023 Google LLC
+#
+# 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
+#
+#      https://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.
+
+OTEL_EXPORTER_GCP_MONITORING_PROJECT_ID = (
+    "OTEL_EXPORTER_GCP_MONITORING_PROJECT_ID"
+)
+"""
+.. envvar:: OTEL_EXPORTER_GCP_MONITORING_PROJECT_ID
+
+    GCP project ID for the exporter to send metrics to. Equivalent to constructor parameter to
+    :class:`opentelemetry.exporter.cloud_monitoring.CloudMonitoringMetricsExporter`.
+"""

opentelemetry-exporter-gcp-monitoring/tests/test_cloud_monitoring_auto_instrument.py

@@ -0,0 +1,37 @@
+# Copyright 2023 Google LLC
+#
+# 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
+#
+#      https://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.
+
+from unittest import TestCase
+
+from opentelemetry.exporter.cloud_monitoring import (
+    CloudMonitoringMetricsExporter,
+)
+
+# private import for testing only
+from opentelemetry.sdk._configuration import _import_exporters
+
+
+class TestCloudTraceAutoInstrument(TestCase):
+    def test_loads_cloud_trace_exporter(self):
+        """Test that OTel configuration internals can load the exporter from entrypoint by
+        name"""
+        _, metric_exporters, _ = _import_exporters(
+            trace_exporter_names=[],
+            log_exporter_names=[],
+            metric_exporter_names=["gcp_monitoring"],
+        )
+        self.assertEqual(
+            metric_exporters,
+            {"gcp_monitoring": CloudMonitoringMetricsExporter},
+        )