Use parent-based OTel sampler by default

CHANGELOG.md

@@ -3,9 +3,12 @@
 ## [Unreleased]
 ### Add
 - Add `IMGPROXY_OPEN_TELEMETRY_GRPC_INSECURE` config.
-- Better XMP data stripping.
 - (pro) Add XMP data to the `/info` response.
 
+### Change
+- Better XMP data stripping.
+- Use parent-based OpenTelemetry sampler by default.
+
 ## [3.10.0] - 2022-11-04
 ### Add
 - Add `IMGPROXY_CLIENT_KEEP_ALIVE_TIMEOUT` config.

metrics/otel/otel.go

@@ -105,7 +105,6 @@ func Init() error {
 
 	tracerProvider = sdktrace.NewTracerProvider(
 		sdktrace.WithResource(res),
-		sdktrace.WithSampler(sdktrace.AlwaysSample()),
 		sdktrace.WithBatcher(traceExporter),
 		sdktrace.WithIDGenerator(idg),
 	)