distro: disable exemplars by default

Since they are not very mature

Author: xrmx

README.md

@@ -79,6 +79,7 @@ This distribution sets the following defaults:
 - `OTEL_METRICS_EXPORTER`: `otlp`
 - `OTEL_EXPORTER_OTLP_PROTOCOL`: `grpc`
 - `OTEL_EXPERIMENTAL_RESOURCE_DETECTORS`: `process_runtime,os,otel,telemetry_distro`
+- `OTEL_METRICS_EXEMPLAR_FILTER`: `always_off`
 
 ### Distribution specific configuration variables
 

src/elasticotel/distro/__init__.py

@@ -30,6 +30,7 @@
 )
 from opentelemetry.sdk._configuration import _OTelSDKConfigurator
 from opentelemetry.sdk.environment_variables import (
+    OTEL_METRICS_EXEMPLAR_FILTER,
     OTEL_EXPERIMENTAL_RESOURCE_DETECTORS,
     OTEL_EXPORTER_OTLP_PROTOCOL,
 )
@@ -68,3 +69,5 @@ def _configure(self, **kwargs):
         os.environ.setdefault(OTEL_LOGS_EXPORTER, "otlp")
         os.environ.setdefault(OTEL_EXPORTER_OTLP_PROTOCOL, "grpc")
         os.environ.setdefault(OTEL_EXPERIMENTAL_RESOURCE_DETECTORS, "process_runtime,os,otel,telemetry_distro")
+        # disable exemplars by default for now
+        os.environ.setdefault(OTEL_METRICS_EXEMPLAR_FILTER, "always_off")

tests/distro/test_distro.py

@@ -25,6 +25,7 @@
     OTEL_TRACES_EXPORTER,
 )
 from opentelemetry.sdk.environment_variables import (
+    OTEL_METRICS_EXEMPLAR_FILTER,
     OTEL_EXPERIMENTAL_RESOURCE_DETECTORS,
     OTEL_EXPORTER_OTLP_PROTOCOL,
 )
@@ -42,6 +43,7 @@ def test_default_configuration(self):
         self.assertEqual(
             "process_runtime,os,otel,telemetry_distro", os.environ.get(OTEL_EXPERIMENTAL_RESOURCE_DETECTORS)
         )
+        self.assertEqual("always_off", os.environ.get(OTEL_METRICS_EXEMPLAR_FILTER))
 
     @mock.patch.dict("os.environ", {}, clear=True)
     def test_load_instrumentor_call_with_default_kwargs_for_SystemMetricsInstrumentor(self):