Fix otel exported names (#3226)

* Fix otel exported names

* based on feedback from OTel devs these settings will become the default

* gofumpt

---------

Co-authored-by: Dave Protasowski <dprotaso@gmail.com>

go.mod

@@ -20,6 +20,7 @@ require (
 	github.com/kelseyhightower/envconfig v1.4.0
 	github.com/openzipkin/zipkin-go v0.4.3
 	github.com/prometheus/client_golang v1.22.0
+	github.com/prometheus/common v0.65.0
 	github.com/spf13/pflag v1.0.6
 	github.com/tsenart/vegeta/v12 v12.12.0
 	go.opencensus.io v0.24.0
@@ -87,7 +88,6 @@ require (
 	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/prometheus/client_model v0.6.2 // indirect
-	github.com/prometheus/common v0.65.0 // indirect
 	github.com/prometheus/procfs v0.16.1 // indirect
 	github.com/prometheus/statsd_exporter v0.22.7 // indirect
 	github.com/rs/dnscache v0.0.0-20230804202142-fc85eb664529 // indirect

observability/metrics/prometheus_enabled.go

@@ -23,13 +23,22 @@ import (
 	"fmt"
 	"net"
 
+	"github.com/prometheus/common/model"
 	otelprom "go.opentelemetry.io/otel/exporters/prometheus"
 	sdkmetric "go.opentelemetry.io/otel/sdk/metric"
 	"knative.dev/pkg/observability/metrics/prometheus"
 )
 
+func init() {
+	//nolint:staticcheck
+	model.NameValidationScheme = model.LegacyValidation
+}
+
 func buildPrometheus(_ context.Context, cfg Config) (sdkmetric.Reader, shutdownFunc, error) {
-	r, err := otelprom.New()
+	r, err := otelprom.New(
+		otelprom.WithoutCounterSuffixes(),
+		otelprom.WithoutUnits(),
+	)
 	if err != nil {
 		return nil, noopFunc, fmt.Errorf("unable to create otel prometheus exporter: %w", err)
 	}