new play metric

it sets playing tracks on 1 and played but non playing tracks to 0. this
also needed a implementation of a watch goroutine that checks the status
of the MPD server each second to set this metric.

assets/prepare/assets.go

@@ -1,10 +1,12 @@
-//nolint:gochecknoglobals,golint,stylecheck
+//nolint:gochecknoglobals
 package prepare
 
 import "embed"
 
+// Files are files to be copied to the system.
 //go:embed files
 var Files embed.FS
 
+// Templates are the used templates for creating file on the system.
 //go:embed templates
 var Templates embed.FS

internal/config/config.go

@@ -7,6 +7,7 @@ import (
 	api "go.xsfx.dev/schnutibox/pkg/api/v1"
 )
 
+// Cfg stores a global config object.
 var Cfg Config
 
 type Config struct {

internal/metrics/metrics.go

@@ -4,18 +4,64 @@ package metrics
 import (
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
+	api "go.xsfx.dev/schnutibox/pkg/api/v1"
 )
 
-var (
-	TracksPlayed = promauto.NewCounterVec(
-		prometheus.CounterOpts{
-			Name: "schnutibox_played_tracks_total",
-		},
-		[]string{"rfid", "name"})
+// Plays is a map of tracked plays.
+// Its a map, so its easier to check if the metric is already initialized
+// and usable. The Key string is the RFID identification.
+var Plays = make(map[string]*api.IdentifyResponse)
 
-	BoxErrors = promauto.NewCounter(
+// NewPlay initialize a new play metric.
+func NewPlay(rfid, name string, uris []string) {
+	if _, ok := Plays[rfid]; !ok {
+		Plays[rfid] = &api.IdentifyResponse{
+			Name: name,
+			Uris: uris,
+		}
+	}
+}
+
+// Play is the play metric.
+var Play = promauto.NewGaugeVec(
+	prometheus.GaugeOpts{
+		Name: "schnutibox_plays",
+		Help: "play metrics",
+	},
+	[]string{"rfid", "name"},
+)
+
+// BoxErrors counts schnutibox errors.
+var BoxErrors = promauto.NewCounter(
 	prometheus.CounterOpts{
-			Name: "schnutbox_errors_total",
+		Name: "schnutibox_errors_total",
+		Help: "counter of errors",
 	},
 )
-)
+
+// tracksEqual checks if uris slices are equal.
+// This is needed to search for the right play item.
+func tracksEqual(a, b []string) bool {
+	if len(a) != len(b) {
+		return false
+	}
+
+	for i, v := range a {
+		if v != b[i] {
+			return false
+		}
+	}
+
+	return true
+}
+
+// Set sets `1` on play gauge if item is playing, a `0` on every other play.
+func Set(uris []string, state string) {
+	for r, p := range Plays {
+		if tracksEqual(uris, p.Uris) && state == "play" {
+			Play.WithLabelValues(r, p.Name).Set(1)
+		} else {
+			Play.WithLabelValues(r, p.Name).Set(0)
+		}
+	}
+}

pkg/prepare/prepare.go

@@ -33,6 +33,7 @@ const (
 	snapclientGroup    = "snapclient"
 )
 
+// Cfg represents the structured data for the schnutibox config file.
 var Cfg = struct {
 	RFIDReader          string
 	ReadOnly            bool

pkg/run/run.go

@@ -3,6 +3,7 @@ package run
 
 import (
 	"fmt"
+	"time"
 
 	"github.com/fhs/gompd/v2/mpd"
 	"github.com/rs/zerolog"
@@ -14,6 +15,8 @@ import (
 	"go.xsfx.dev/schnutibox/pkg/web"
 )
 
+const TickerTime = time.Second
+
 type mpc struct {
 	conn *mpd.Client
 }
@@ -37,9 +40,6 @@ func (m *mpc) clear(logger zerolog.Logger) error {
 func (m *mpc) play(logger zerolog.Logger, rfid string, name string, uris []string) error {
 	logger.Info().Msg("trying to add tracks")
 
-	// Metric labels.
-	mLabels := []string{rfid, name}
-
 	// Stop playing track.
 	if err := m.stop(logger); err != nil {
 		metrics.BoxErrors.Inc()
@@ -65,11 +65,60 @@ func (m *mpc) play(logger zerolog.Logger, rfid string, name string, uris []strin
 		}
 	}
 
-	metrics.TracksPlayed.WithLabelValues(mLabels...).Inc()
+	metrics.NewPlay(rfid, name, uris)
 
 	return m.conn.Play(-1)
 }
 
+func (m *mpc) watch() {
+	log.Debug().Msg("starting watch")
+
+	ticker := time.NewTicker(TickerTime)
+
+	go func() {
+		for {
+			<-ticker.C
+
+			// Check if we can connect to MPD server.
+			if err := m.conn.Ping(); err != nil {
+				log.Error().Err(err).Msg("could not ping MPD server")
+				metrics.BoxErrors.Inc()
+
+				continue
+			}
+
+			// Getting playlist info.
+			attrs, err := m.conn.PlaylistInfo(-1, -1)
+			if err != nil {
+				log.Error().Err(err).Msg("could not get playlist info")
+				metrics.BoxErrors.Inc()
+
+				continue
+			}
+
+			// Stores the tracklist it got from the MPD server.
+			uris := []string{}
+
+			// Builds uri list.
+			for _, a := range attrs {
+				uris = append(uris, a["file"])
+			}
+
+			// Gettings MPD state.
+			s, err := m.conn.Status()
+			if err != nil {
+				log.Error().Err(err).Msg("could not get status")
+				metrics.BoxErrors.Inc()
+
+				continue
+			}
+
+			// Sets the metrics.
+			metrics.Set(uris, s["state"])
+		}
+	}()
+}
+
 func Run(cmd *cobra.Command, args []string) {
 	log.Info().Msg("starting the RFID reader")
 
@@ -80,6 +129,16 @@ func Run(cmd *cobra.Command, args []string) {
 		log.Fatal().Err(err).Msg("could not start RFID reader")
 	}
 
+	// Create MPD connection on every received event.
+	c, err := mpd.Dial("tcp", fmt.Sprintf("%s:%d", config.Cfg.MPD.Hostname, config.Cfg.MPD.Port))
+	if err != nil {
+		log.Fatal().Err(err).Msg("could not connect to MPD server")
+	}
+
+	m := newMpc(c)
+
+	m.watch()
+
 	go func() {
 		var id string
 
@@ -89,16 +148,6 @@ func Run(cmd *cobra.Command, args []string) {
 			logger := log.With().Str("id", id).Logger()
 			logger.Info().Msg("received id")
 
-			// Create MPD connection on every received event.
-			c, err := mpd.Dial("tcp", fmt.Sprintf("%s:%d", config.Cfg.MPD.Hostname, config.Cfg.MPD.Port))
-			if err != nil {
-				logger.Error().Err(err).Msg("could not connect to MPD server")
-
-				continue
-			}
-
-			m := newMpc(c)
-
 			// Check of stop tag was detected.
 			if id == config.Cfg.Meta.Stop {
 				logger.Info().Msg("stopping")