add additional latency metrics for few service calls

Signed-off-by: Kush Sharma <thekushsharma@gmail.com>

core/authenticate/service.go

@@ -23,6 +23,7 @@ import (
 	frontiersession "github.com/raystack/frontier/core/authenticate/session"
 	"github.com/raystack/frontier/core/serviceuser"
 	"github.com/raystack/frontier/internal/bootstrap/schema"
+	"github.com/raystack/frontier/internal/metrics"
 	"github.com/raystack/frontier/pkg/errors"
 
 	"github.com/lestrrat-go/jwx/v2/jwk"
@@ -739,6 +740,11 @@ func (s Service) getOrCreateUser(ctx context.Context, email, title string) (user
 }
 
 func (s Service) GetPrincipal(ctx context.Context, assertions ...ClientAssertion) (Principal, error) {
+	if metrics.ServiceOprLatency != nil {
+		promCollect := metrics.ServiceOprLatency("authenticate", "GetPrincipal")
+		defer promCollect()
+	}
+
 	var currentPrincipal Principal
 	if len(assertions) == 0 {
 		// check all assertions

core/organization/service.go

@@ -18,6 +18,7 @@ import (
 	"github.com/raystack/frontier/core/relation"
 	"github.com/raystack/frontier/core/user"
 	"github.com/raystack/frontier/internal/bootstrap/schema"
+	"github.com/raystack/frontier/internal/metrics"
 )
 
 type Repository interface {
@@ -229,6 +230,11 @@ func (s Service) Update(ctx context.Context, org Organization) (Organization, er
 }
 
 func (s Service) ListByUser(ctx context.Context, principal authenticate.Principal, filter Filter) ([]Organization, error) {
+	if metrics.ServiceOprLatency != nil {
+		promCollect := metrics.ServiceOprLatency("organization", "ListByUser")
+		defer promCollect()
+	}
+
 	subjectIDs, err := s.relationService.LookupResources(ctx, relation.Relation{
 		Object: relation.Object{
 			Namespace: schema.OrganizationNamespace,

internal/metrics/metrics.go

@@ -9,6 +9,7 @@ import (
 func Init() {
 	initStripe()
 	initDB()
+	initService()
 }
 
 type HistogramFunc func(labelValue ...string) func()

internal/metrics/service.go

@@ -0,0 +1,16 @@
+package metrics
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+)
+
+var ServiceOprLatency HistogramFunc
+
+func initService() {
+	ServiceOprLatency = createMeasureTime(promauto.NewHistogramVec(prometheus.HistogramOpts{
+		Name:    "service_method_latency",
+		Help:    "Time taken for service operation to complete",
+		Buckets: []float64{.005, .01, .025, .05, .1, .25, .5, 1, 2.5, 5, 10, 30, 60},
+	}, []string{"service", "operation"}))
+}