feat: provide metrics endpoint (#3902)

* feat: provide metrics endpoint

* config

* enable otel metrics by default

Co-authored-by: Florian Forster <florian@caos.ch>

cmd/defaults.yaml

@@ -3,6 +3,11 @@ Log:
   Formatter:
     Format: text
 
+# Exposes metrics on /debug/metrics
+Metrics:
+  # Select type otel (OpenTelemetry) or none (disables collection and endpoint)
+  Type: otel
+
 # Port ZITADEL will listen on
 Port: 8080
 # Port ZITADEL is exposed on, it can differ from port e.g. if you proxy the traffic

cmd/start/config.go

@@ -22,6 +22,7 @@ import (
 	"github.com/zitadel/zitadel/internal/database"
 	"github.com/zitadel/zitadel/internal/query/projection"
 	static_config "github.com/zitadel/zitadel/internal/static/config"
+	metrics "github.com/zitadel/zitadel/internal/telemetry/metrics/config"
 	tracing "github.com/zitadel/zitadel/internal/telemetry/tracing/config"
 )
 
@@ -37,6 +38,7 @@ type Config struct {
 	WebAuthNName      string
 	Database          database.Config
 	Tracing           tracing.Config
+	Metrics           metrics.Config
 	Projections       projection.Config
 	Auth              auth_es.Config
 	Admin             admin_es.Config
@@ -65,12 +67,17 @@ func MustNewConfig(v *viper.Viper) *Config {
 			mapstructure.StringToSliceHookFunc(","),
 		)),
 	)
+	logging.OnError(err).Fatal("unable to read config")
+
 	err = config.Log.SetLogger()
 	logging.OnError(err).Fatal("unable to set logger")
 
 	err = config.Tracing.NewTracer()
 	logging.OnError(err).Fatal("unable to set tracer")
 
+	err = config.Metrics.NewMeter()
+	logging.OnError(err).Fatal("unable to set meter")
+
 	return config
 }