feat: add metrics

cmd/api/main.go

@@ -9,6 +9,9 @@ import (
 
 	"github.com/getsentry/sentry-go"
 	"github.com/gofiber/fiber/v2"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	log "github.com/sirupsen/logrus"
 
 	"github.com/packetframe/vertex/internal/config"
@@ -22,6 +25,13 @@ var (
 	sentryDsn = os.Getenv("SENTRY_DSN")
 )
 
+var (
+	metricRules = promauto.NewGauge(prometheus.GaugeOpts{
+		Name: "packetframe_vertex_rules",
+		Help: "Total vertex rules accounts",
+	})
+)
+
 // response returns a JSON response
 func response(c *fiber.Ctx, status int, message string, data map[string]interface{}) error {
 	// Capitalize first letter
@@ -78,6 +88,8 @@ func main() {
 				log.Warnf("unable to retreive rules: %s", err)
 			}
 
+			metricRules.Set(float64(len(rules)))
+
 			for _, rule := range rules {
 				if time.Since(rule.CreatedAt) > rule.Expire {
 					log.Debugln("Found expired rule, deleting")
@@ -170,7 +182,12 @@ func main() {
 		return c.Status(http.StatusOK).SendString(cfg.String())
 	})
 
-	// go metrics.Listen(metricsListen)
+	// Start metrics server
+	go func() {
+		http.Handle("/metrics", promhttp.Handler())
+		log.Info("Starting metrics exporter on http://:8081/metrics")
+		log.Fatal(http.ListenAndServe(":8081", nil))
+	}()
 
 	startupMessage := fmt.Sprintf("Starting API %s on :8080", version)
 	sentry.CaptureMessage(startupMessage)

go.mod

@@ -6,7 +6,8 @@ require (
 	github.com/getsentry/sentry-go v0.13.0
 	github.com/gofiber/fiber/v2 v2.32.0
 	github.com/jedib0t/go-pretty/v6 v6.3.1
-	github.com/sirupsen/logrus v1.4.2
+	github.com/prometheus/client_golang v1.12.1
+	github.com/sirupsen/logrus v1.6.0
 	github.com/spf13/cobra v1.4.0
 	github.com/stretchr/testify v1.7.1
 	gorm.io/driver/postgres v1.3.5
@@ -15,7 +16,10 @@ require (
 
 require (
 	github.com/andybalholm/brotli v1.0.4 // indirect
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/cespare/xxhash/v2 v2.1.2 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
 	github.com/inconshreveable/mousetrap v1.0.0 // indirect
 	github.com/jackc/chunkreader/v2 v2.0.1 // indirect
 	github.com/jackc/pgconn v1.12.0 // indirect
@@ -28,9 +32,13 @@ require (
 	github.com/jinzhu/inflection v1.0.0 // indirect
 	github.com/jinzhu/now v1.1.4 // indirect
 	github.com/klauspost/compress v1.15.0 // indirect
-	github.com/konsorten/go-windows-terminal-sequences v1.0.2 // indirect
+	github.com/konsorten/go-windows-terminal-sequences v1.0.3 // indirect
 	github.com/mattn/go-runewidth v0.0.13 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/prometheus/client_model v0.2.0 // indirect
+	github.com/prometheus/common v0.32.1 // indirect
+	github.com/prometheus/procfs v0.7.3 // indirect
 	github.com/rivo/uniseg v0.2.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
@@ -39,5 +47,6 @@ require (
 	golang.org/x/crypto v0.0.0-20220214200702-86341886e292 // indirect
 	golang.org/x/sys v0.0.0-20220227234510-4e6760a101f9 // indirect
 	golang.org/x/text v0.3.7 // indirect
+	google.golang.org/protobuf v1.26.0 // indirect
 	gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c // indirect
 )