feat(spans): Add a feature to control double writing distributions as gauges (#69344)

src/sentry/conf/server.py

@@ -2013,6 +2013,7 @@ SENTRY_FEATURES: dict[str, bool | None] = {
     "projects:span-metrics-extraction-resource": False,
     "projects:discard-transaction": False,
     "projects:extract-transaction-from-segment-span": False,
+    "projects:span-metrics-double-write-distributions-as-gauges": False,
     # Controls whether or not the relocation endpoints can be used.
     "relocation:enabled": False,
     # NOTE: Don't add feature defaults down here! Please add them in their associated

src/sentry/features/temporary.py

@@ -283,6 +283,7 @@ def register_temporary_features(manager: FeatureManager):
     manager.add("projects:span-metrics-extraction-ga-modules", ProjectFeature, FeatureHandlerStrategy.INTERNAL)
     manager.add("projects:span-metrics-extraction-resource", ProjectFeature, FeatureHandlerStrategy.INTERNAL)
     manager.add("projects:extract-transaction-from-segment-span", ProjectFeature, FeatureHandlerStrategy.INTERNAL)
+    manager.add("projects:span-metrics-double-write-distributions-as-gauges", ProjectFeature, FeatureHandlerStrategy.INTERNAL)
 
     # Project plugin features
     manager.add("projects:plugins", ProjectPluginFeature, FeatureHandlerStrategy.INTERNAL)

src/sentry/relay/config/__init__.py

@@ -76,6 +76,7 @@ EXPOSABLE_FEATURES = [
     "projects:span-metrics-extraction-ga-modules",
     "projects:span-metrics-extraction-resource",
     "projects:span-metrics-extraction",
+    "projects:span-metrics-double-write-distributions-as-gauges",
 ]
 
 EXTRACT_METRICS_VERSION = 1