Add prometheus metrics

godoor.go

@@ -7,6 +7,9 @@ import (
 	"encoding/json"
 	"fmt"
 	"github.com/joho/godotenv"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"io"
 	"log"
 	"net/http"
@@ -56,6 +59,7 @@ type Config struct {
 		wiegandB int
 		solenoid int
 	}
+	prometheusMetricsBind string
 }
 
 type KeepDoorOpen struct {
@@ -88,17 +92,42 @@ var validUids ValidUids
 var wiegand Wiegand
 var keepDoorOpen KeepDoorOpen
 
-var lastSyncedTimestamp *time.Time
-var openDoorTimestamps []OpenedTimestamp
+var (
+	godoorBuildInfo = promauto.NewGaugeVec(prometheus.GaugeOpts{
+		Name: "godoor_build_info",
+		Help: "Build Information",
+	}, []string{"version", "revision"})
+	lastSyncTimestamp = promauto.NewGauge(prometheus.GaugeOpts{
+		Name: "godoor_last_allow_list_sync_timestamp_seconds",
+		Help: "Last time list of card hashes was pulled from the server",
+	})
+	apiFailuresCount = promauto.NewCounterVec(prometheus.CounterOpts{
+		Name: "godoor_api_request_failures_total",
+		Help: "HTTP API request failures count",
+	}, []string{"api", "endpoint"})
+	nrCardsInAllowList = promauto.NewGauge(prometheus.GaugeOpts{
+		Name: "godoor_allowed_card_hashes_total",
+		Help: "Number of card hashes in memory that can open the door",
+	})
+	doorOpenedCount = promauto.NewCounterVec(prometheus.CounterOpts{
+		Name: "godoor_door_opens_total",
+		Help: "Number of times door was opened",
+	}, []string{"source"})
+	cardSwipesCount = promauto.NewCounterVec(prometheus.CounterOpts{
+		Name: "godoor_swipes_total",
+		Help: "Number of times a card has been swiped",
+	}, []string{"status"})
+)
 
 func main() {
-
 	log.Printf("GoDoor ver: %s (%s)", Version, Commit)
 	ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
 	defer cancel()
 
 	loadConfig()
 
+	godoorBuildInfo.WithLabelValues(Version, Commit).Set(1)
+
 	go func() {
 		setup()
 	}()
@@ -129,6 +158,10 @@ func loadConfig() {
 		config.doorOpenTime = 3
 	}
 	_, config.mock = os.LookupEnv("KDOORPI_MOCK_HW")
+	config.prometheusMetricsBind = os.Getenv("KDOORPI_PROMETHEUS_METRICS_BIND")
+	if config.prometheusMetricsBind == "" {
+		config.prometheusMetricsBind = ":3334"
+	}
 
 	config.pins.wiegandA, err = strconv.Atoi(os.Getenv("KDOORPI_PIN_WIEGAND_A"))
 	if err != nil {
@@ -158,16 +191,24 @@ func setup() {
 	}
 	log.Println("HW Setup done")
 
+	go runHttpServer()
+
 	http.DefaultClient.Timeout = 120 * time.Second
 
 	go func() {
 		for {
 			err := waitEvents()
 			if err != nil {
+				apiFailuresCount.WithLabelValues("longpoll", config.api.longpoll).Inc()
 				log.Printf("LongPoll for events failed: %v", err)
 				log.Println("Will try to LongPoll again in 120 seconds")
 				time.Sleep(120 * time.Second)
-				go reloadTokens()
+				go func() {
+					err := reloadTokens()
+					if err != nil {
+						apiFailuresCount.WithLabelValues("allowed", config.api.allowed).Inc()
+					}
+				}()
 			}
 			time.Sleep(1 * time.Second)
 		}
@@ -181,13 +222,12 @@ func setup() {
 		if err == nil {
 			break
 		}
+		apiFailuresCount.WithLabelValues("allowed", config.api.allowed).Inc()
 		log.Printf("Initial token population failed. err: %v", err)
 		log.Println("Retrying in 10 seconds...")
 		time.Sleep(10 * time.Second)
 	}
 
-	go runHttpServer()
-
 	log.Println("Initial token population success")
 
 	go cardRunner(wiegand)
@@ -196,26 +236,9 @@ func setup() {
 }
 
 func runHttpServer() {
-	http.HandleFunc("/lastsync", func(w http.ResponseWriter, r *http.Request) {
-		e := json.NewEncoder(w)
-		e.Encode(map[string]any{
-			"last_synced": lastSyncedTimestamp,
-		})
-	})
-	http.HandleFunc("/opened", func(w http.ResponseWriter, r *http.Request) {
-		e := json.NewEncoder(w)
-		e.Encode(map[string]any{
-			"open_timestamps": openDoorTimestamps,
-		})
-	})
-	http.HandleFunc("/isopen", func(w http.ResponseWriter, r *http.Request) {
-		e := json.NewEncoder(w)
-		open, _ := wiegand.IsDoorOpen()
-		e.Encode(map[string]any{
-			"open": open,
-		})
-	})
-	http.ListenAndServe(":3334", nil)
+	http.Handle("/metrics", promhttp.Handler())
+	log.Printf("Running prometheus metrics on http://%s/metrics", config.prometheusMetricsBind)
+	log.Fatal(http.ListenAndServe(config.prometheusMetricsBind, nil))
 }
 
 func OpenAndCloseDoor(w Wiegand) error {
@@ -248,7 +271,6 @@ func OpenDoor(w Wiegand) error {
 		return nil
 	}
 	w.OpenDoor()
-	openDoorTimestamps = append(openDoorTimestamps, OpenedTimestamp{Opened: time.Now(), Closed: nil})
 	return nil
 }
 
@@ -258,8 +280,6 @@ func CloseDoor(w Wiegand) error {
 		return nil
 	}
 	w.CloseDoor()
-	t := time.Now()
-	openDoorTimestamps[len(openDoorTimestamps)-1].Closed = &t
 	return nil
 }
 
@@ -281,6 +301,7 @@ func cardRunner(w Wiegand) {
 		go func() {
 			err := sendSwipeEvent(hashedHex, ok)
 			if err != nil {
+				apiFailuresCount.WithLabelValues("swipe", config.api.swipe).Inc()
 				log.Println("Failed to send swipe event: %v", err)
 			}
 		}()
@@ -288,10 +309,13 @@ func cardRunner(w Wiegand) {
 		if ok {
 			log.Println("Opening door")
 			err := OpenAndCloseDoor(w)
+			cardSwipesCount.WithLabelValues("accepted").Inc()
+			doorOpenedCount.WithLabelValues("card").Inc()
 			if err != nil {
 				log.Println("There was an error opening and closing the Door")
 			}
 		} else {
+			cardSwipesCount.WithLabelValues("denied").Inc()
 			log.Println("Unknown card")
 		}
 
@@ -349,6 +373,7 @@ func waitEvents() error {
 			log.Printf("got server data: %q\n", data)
 			if strings.TrimSpace(data) == config.door {
 				err := OpenAndCloseDoor(wiegand)
+				doorOpenedCount.WithLabelValues("api").Inc()
 				if err != nil {
 					log.Println("There was an error opening and closing the Door")
 				}
@@ -397,13 +422,13 @@ func reloadTokens() error {
 		totalCardCount = i
 	}
 	log.Printf("Got %d cards from server", totalCardCount)
+	nrCardsInAllowList.Set(float64(totalCardCount))
 
 	if cl.KeepOpenUntil != nil {
 		updateKeepOpenDoor(*cl.KeepOpenUntil)
 	}
 
-	t := time.Now()
-	lastSyncedTimestamp = &t
+	lastSyncTimestamp.SetToCurrentTime()
 
 	return nil
 }