feat: reporting basic metrics to prometheus

main.go

@@ -7,6 +7,7 @@ import (
 	"log"
 	"net/http"
 
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/redis/go-redis/v9"
 
 	"sunshine.industries/some-automoderation/rooms"
@@ -19,10 +20,20 @@ var ctx = context.Background()
 func main() {
 	var port int
 	flag.IntVar(&port, "port", 8080, "Port on which the server should start")
+	var metricsPort int
+	flag.IntVar(&metricsPort, "metricsPort", 8081, "Port on which the server expose metrics")
 	var redisPort int
 	flag.IntVar(&redisPort, "redisPort", 7777, "Port on which server should connect to redis db")
 	flag.Parse()
 
+	promHandler := promhttp.Handler()
+	promMux := http.NewServeMux()
+	promMux.Handle("/metrics", promHandler)
+
+	go func() {
+		log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", metricsPort), promMux))
+	}()
+
 	rdb := redis.NewClient(&redis.Options{
 		Addr: fmt.Sprintf("localhost:%d", redisPort),
 		Password: "",
@@ -32,7 +43,7 @@ func main() {
 	roomsM := rooms.RedisRM { Rdb: rdb, }
 	sessions := sessions.RedisSM{ Rdb: rdb, }
 
-	log.Printf("Server will start on port: %d; listening to redis on: %d\n", port, redisPort)
+	log.Printf("Server will start on port: %d; /metrics on %d; listening to redis on: %d\n", port, metricsPort, redisPort)
 	routes.RegisterRoutes(sessions, roomsM)
 
 	log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", port), nil))