Init dualwriter metrics (#89003)

* Pass prometheus registerer to the dual writer

* Fix tests

* Remove unused var

* Fix tests

* Uncomment test

* Remove leading line

* Fix tests. Reuse registerer if there's already one

* Lint

* Improve double registering logic

* Rebase main

pkg/services/apiserver/aggregator/aggregator.go

@@ -24,6 +24,7 @@ import (
 
 	servicev0alpha1 "github.com/grafana/grafana/pkg/apis/service/v0alpha1"
 	"github.com/grafana/grafana/pkg/registry/apis/service"
+	"github.com/prometheus/client_golang/prometheus"
 	"gopkg.in/yaml.v3"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime/schema"
@@ -172,7 +173,7 @@ func CreateAggregatorConfig(commandOptions *options.Options, sharedConfig generi
 	return NewConfig(aggregatorConfig, sharedInformerFactory, []builder.APIGroupBuilder{serviceAPIBuilder}, remoteServicesConfig), nil
 }
 
-func CreateAggregatorServer(config *Config, delegateAPIServer genericapiserver.DelegationTarget) (*aggregatorapiserver.APIAggregator, error) {
+func CreateAggregatorServer(config *Config, delegateAPIServer genericapiserver.DelegationTarget, reg prometheus.Registerer) (*aggregatorapiserver.APIAggregator, error) {
 	aggregatorConfig := config.KubeAggregatorConfig
 	sharedInformerFactory := config.Informers
 	remoteServicesConfig := config.RemoteServicesConfig
@@ -285,7 +286,13 @@ func CreateAggregatorServer(config *Config, delegateAPIServer genericapiserver.D
 	})
 
 	for _, b := range config.Builders {
-		serviceAPIGroupInfo, err := b.GetAPIGroupInfo(aggregatorscheme.Scheme, aggregatorscheme.Codecs, aggregatorConfig.GenericConfig.RESTOptionsGetter, grafanarest.Mode0)
+		serviceAPIGroupInfo, err := b.GetAPIGroupInfo(
+			aggregatorscheme.Scheme,
+			aggregatorscheme.Codecs,
+			aggregatorConfig.GenericConfig.RESTOptionsGetter,
+			grafanarest.Mode0,
+			reg,
+		)
 		if err != nil {
 			return nil, err
 		}

pkg/services/apiserver/service.go

@@ -7,6 +7,7 @@ import (
 	"path"
 
 	"github.com/grafana/dskit/services"
+	"github.com/prometheus/client_golang/prometheus"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials/insecure"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -24,6 +25,7 @@ import (
 	filestorage "github.com/grafana/grafana/pkg/apiserver/storage/file"
 	"github.com/grafana/grafana/pkg/infra/appcontext"
 	"github.com/grafana/grafana/pkg/infra/db"
+	"github.com/grafana/grafana/pkg/infra/metrics"
 	"github.com/grafana/grafana/pkg/infra/tracing"
 	"github.com/grafana/grafana/pkg/middleware"
 	"github.com/grafana/grafana/pkg/modules"
@@ -109,6 +111,7 @@ type service struct {
 	builders []builder.APIGroupBuilder
 
 	tracing *tracing.TracingService
+	metrics prometheus.Registerer
 
 	authorizer *authorizer.GrafanaAuthorizer
 }
@@ -131,6 +134,7 @@ func ProvideService(
 		authorizer: authorizer.NewGrafanaAuthorizer(cfg, orgService),
 		tracing:    tracing,
 		db:         db, // For Unified storage
+		metrics:    metrics.ProvideRegisterer(),
 	}
 
 	// This will be used when running as a dskit service
@@ -314,7 +318,7 @@ func (s *service) start(ctx context.Context) error {
 	}
 
 	// Install the API group+version
-	err = builder.InstallAPIs(Scheme, Codecs, server, serverConfig.RESTOptionsGetter, builders, o.StorageOptions)
+	err = builder.InstallAPIs(Scheme, Codecs, server, serverConfig.RESTOptionsGetter, builders, o.StorageOptions, s.metrics)
 	if err != nil {
 		return err
 	}
@@ -324,7 +328,7 @@ func (s *service) start(ctx context.Context) error {
 
 	var runningServer *genericapiserver.GenericAPIServer
 	if s.features.IsEnabledGlobally(featuremgmt.FlagKubernetesAggregator) {
-		runningServer, err = s.startAggregator(transport, serverConfig, server)
+		runningServer, err = s.startAggregator(transport, serverConfig, server, s.metrics)
 		if err != nil {
 			return err
 		}
@@ -374,6 +378,7 @@ func (s *service) startAggregator(
 	transport *roundTripperFunc,
 	serverConfig *genericapiserver.RecommendedConfig,
 	server *genericapiserver.GenericAPIServer,
+	reg prometheus.Registerer,
 ) (*genericapiserver.GenericAPIServer, error) {
 	namespaceMapper := request.GetNamespaceMapper(s.cfg)
 
@@ -382,7 +387,7 @@ func (s *service) startAggregator(
 		return nil, err
 	}
 
-	aggregatorServer, err := aggregator.CreateAggregatorServer(aggregatorConfig, server)
+	aggregatorServer, err := aggregator.CreateAggregatorServer(aggregatorConfig, server, reg)
 	if err != nil {
 		return nil, err
 	}

pkg/services/apiserver/standalone/options/metrics.go

@@ -15,7 +15,7 @@ type MetricsOptions struct {
 	MetricsRegisterer prometheus.Registerer
 }
 
-func NewMetrcicsOptions(logger log.Logger) *MetricsOptions {
+func NewMetricsOptions(logger log.Logger) *MetricsOptions {
 	return &MetricsOptions{
 		logger: logger,
 	}

pkg/services/apiserver/standalone/options/options.go

@@ -25,7 +25,7 @@ func New(logger log.Logger, codec runtime.Codec) *Options {
 		ExtraOptions:       options.NewExtraOptions(),
 		RecommendedOptions: options.NewRecommendedOptions(codec),
 		TracingOptions:     NewTracingOptions(logger),
-		MetricsOptions:     NewMetrcicsOptions(logger),
+		MetricsOptions:     NewMetricsOptions(logger),
 		ServerRunOptions:   genericoptions.NewServerRunOptions(),
 		StorageOptions:     options.NewStorageOptions(),
 	}