Use otel metrics by default

common/metrics/config.go

@@ -461,19 +461,21 @@ func MetricsHandlerFromConfig(logger log.Logger, c *Config) (Handler, error) {
 
 	setDefaultPerUnitHistogramBoundaries(&c.ClientConfig)
 
-	if c.Prometheus != nil && c.Prometheus.Framework == FrameworkOpentelemetry {
-		otelProvider, err := NewOpenTelemetryProvider(logger, c.Prometheus, &c.ClientConfig)
-		if err != nil {
-			logger.Fatal(err.Error())
-		}
+	if c.Prometheus != nil && c.Prometheus.Framework == FrameworkTally {
+		// only use tally if specifically asked to do so, will remove tally in future server version.
+		return NewTallyMetricsHandler(
+			c.ClientConfig,
+			NewScope(logger, c),
+		), nil
+	}
 
-		return NewOtelMetricsHandler(logger, otelProvider, c.ClientConfig)
+	// if not specified, default to use otel
+	otelProvider, err := NewOpenTelemetryProvider(logger, c.Prometheus, &c.ClientConfig)
+	if err != nil {
+		logger.Fatal(err.Error())
 	}
 
-	return NewTallyMetricsHandler(
-		c.ClientConfig,
-		NewScope(logger, c),
-	), nil
+	return NewOtelMetricsHandler(logger, otelProvider, c.ClientConfig)
 }
 
 func configExcludeTags(cfg ClientConfig) map[string]map[string]struct{} {

common/metrics/config_test.go

@@ -196,6 +196,16 @@ func TestMetricsHandlerFromConfig(t *testing.T) {
 			},
 			expectedType: &otelMetricsHandler{},
 		},
+		{
+			name: "", // default to otel
+			cfg: &Config{
+				Prometheus: &PrometheusConfig{
+					Framework:     FrameworkOpentelemetry,
+					ListenAddress: "localhost:0",
+				},
+			},
+			expectedType: &otelMetricsHandler{},
+		},
 	} {
 		c := c
 		t.Run(c.name, func(t *testing.T) {