Add Prometheus metrics for number of plays. Add buffer for mpg123

player/go.mod

@@ -1,3 +1,16 @@
 module go_rfid
 
 go 1.21.3
+
+require (
+	github.com/beorn7/perks v1.0.1 // indirect
+	github.com/cespare/xxhash/v2 v2.2.0 // indirect
+	github.com/golang/protobuf v1.5.3 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.4 // indirect
+	github.com/prometheus/client_golang v1.17.0 // indirect
+	github.com/prometheus/client_model v0.4.1-0.20230718164431-9a2bf3000d16 // indirect
+	github.com/prometheus/common v0.44.0 // indirect
+	github.com/prometheus/procfs v0.11.1 // indirect
+	golang.org/x/sys v0.11.0 // indirect
+	google.golang.org/protobuf v1.31.0 // indirect
+)

player/go.sum

@@ -0,0 +1,27 @@
+github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
+github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
+github.com/cespare/xxhash/v2 v2.2.0 h1:DC2CZ1Ep5Y4k3ZQ899DldepgrayRUGE6BBZ/cd9Cj44=
+github.com/cespare/xxhash/v2 v2.2.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
+github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
+github.com/golang/protobuf v1.5.3 h1:KhyjKVUg7Usr/dYsdSqoFveMYd5ko72D+zANwlG1mmg=
+github.com/golang/protobuf v1.5.3/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
+github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/matttproud/golang_protobuf_extensions v1.0.4 h1:mmDVorXM7PCGKw94cs5zkfA9PSy5pEvNWRP0ET0TIVo=
+github.com/matttproud/golang_protobuf_extensions v1.0.4/go.mod h1:BSXmuO+STAnVfrANrmjBb36TMTDstsz7MSK+HVaYKv4=
+github.com/prometheus/client_golang v1.17.0 h1:rl2sfwZMtSthVU752MqfjQozy7blglC+1SOtjMAMh+Q=
+github.com/prometheus/client_golang v1.17.0/go.mod h1:VeL+gMmOAxkS2IqfCq0ZmHSL+LjWfWDUmp1mBz9JgUY=
+github.com/prometheus/client_model v0.4.1-0.20230718164431-9a2bf3000d16 h1:v7DLqVdK4VrYkVD5diGdl4sxJurKJEMnODWRJlxV9oM=
+github.com/prometheus/client_model v0.4.1-0.20230718164431-9a2bf3000d16/go.mod h1:oMQmHW1/JoDwqLtg57MGgP/Fb1CJEYF2imWWhWtMkYU=
+github.com/prometheus/common v0.44.0 h1:+5BrQJwiBB9xsMygAB3TNvpQKOwlkc25LbISbrdOOfY=
+github.com/prometheus/common v0.44.0/go.mod h1:ofAIvZbQ1e/nugmZGz4/qCb9Ap1VoSTIO7x0VV9VvuY=
+github.com/prometheus/procfs v0.11.1 h1:xRC8Iq1yyca5ypa9n1EZnWZkt7dwcoRPQwX/5gwaUuI=
+github.com/prometheus/procfs v0.11.1/go.mod h1:eesXgaPo1q7lBpVMoMy0ZOFTth9hBn4W/y0/p/ScXhY=
+golang.org/x/sync v0.0.0-20181221193216-37e7f081c4d4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.11.0 h1:eG7RXZHdqOJ1i+0lgLgCpSXAp6M3LYlAo6osgSi0xOM=
+golang.org/x/sys v0.11.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
+google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
+google.golang.org/protobuf v1.31.0 h1:g0LDEJHgrBl9N9r17Ru3sqWhkIx2NB67okBHPwC7hs8=
+google.golang.org/protobuf v1.31.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=

player/main.go

@@ -8,30 +8,50 @@ import (
 	"os/exec"
 	"sync"
 	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
 var (
-	mu         sync.Mutex
-	previousID string
-	timeout    = 8 * time.Second
-	timer      *time.Timer
-	jsonData   map[string]map[string]interface{}
-	isPlaying  bool
+	mu           sync.Mutex
+	lastPlayedID string
+	timeout      = 3500 * time.Millisecond
+	timer        *time.Timer
+	jsonData     map[string]map[string]interface{}
+	isPlaying    bool
+)
+
+// Define a Prometheus Counter to track the number of plays for each track ID.
+var playsCounter = prometheus.NewCounterVec(
+	prometheus.CounterOpts{
+		Name: "track_plays_total",
+		Help: "Total number of plays for each track ID.",
+	},
+	[]string{"track_id"},
 )
 
 type PostData struct {
 	ID string `json:"id"`
 }
 
-func playMP3(filePath string, offset int) {
-	if isPlaying {
-		fmt.Println("Music is already playing.")
+func init() {
+	// Register the Prometheus metrics.
+	prometheus.MustRegister(playsCounter)
+}
+
+func playMP3(filePath string, offset int, currentID string) {
+	if isPlaying && currentID == lastPlayedID {
+		fmt.Println("This track is already playing.")
 		return
+	} else if isPlaying {
+		fmt.Println("Music is already playing, but starting new track.")
+		stopMP3()
 	}
 
 	isPlaying = true
 
-	cmd := exec.Command("mpg123", fmt.Sprintf("-k %d", offset), filePath)
+	cmd := exec.Command("mpg123", "-q", "-b", "512", fmt.Sprintf("-k %d", offset), filePath)
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
 
@@ -53,6 +73,7 @@ func stopMP3() {
 		if err != nil {
 			fmt.Println("Error stopping MP3:", err)
 		}
+		isPlaying = false
 	}
 }
 
@@ -77,16 +98,30 @@ func playHandler(w http.ResponseWriter, r *http.Request) {
 	mu.Lock()
 	defer mu.Unlock()
 
-	if currentID == previousID {
-		fmt.Printf("Received the same ID again. Current ID: %s, Previous ID: %s\n", currentID, previousID)
-		// Reset the timer
-		if timer != nil {
-			timer.Stop()
+	// Check if something is playing now
+	if isPlaying {
+		if currentID != lastPlayedID {
+			// If something is already playing, and it's not the same as the incoming ID
+			fmt.Printf("Stopping the previous track (ID: %s) and starting the new track (ID: %s)\n", lastPlayedID, currentID)
+			stopMP3()
+			lastPlayedID = currentID
+		} else {
+			// If the same ID is requested again
+			fmt.Printf("Received the same ID again (ID: %s). Current track remains unchanged.\n", currentID)
+			// Reset the timer
+			if timer != nil {
+				timer.Stop()
+			}
 		}
 	} else {
-		previousID = currentID
+		// If nothing is playing, start playing the song
+		fmt.Printf("Starting to play the track (ID: %s)\n", currentID)
+		lastPlayedID = currentID
 	}
 
+	// Increment the playsCounter metric for the current track ID.
+	playsCounter.WithLabelValues(currentID).Inc()
+
 	// Start or reset the timer
 	if timer != nil {
 		timer.Stop()
@@ -105,7 +140,10 @@ func playHandler(w http.ResponseWriter, r *http.Request) {
 		filePath, _ := data["file"].(string)
 		offset, ok := data["offset"].(float64)
 		if ok {
-			playMP3("../"+filePath, int(offset))
+			if isPlaying == true {
+				fmt.Println("")
+			}
+			playMP3("../"+filePath, int(offset), currentID)
 		} else {
 			fmt.Println("Offset field not found in JSON for ID:", currentID)
 		}
@@ -143,6 +181,9 @@ func main() {
 	// Define the route and handler for /play
 	router.HandleFunc("/play", playHandler)
 
+	// Define a new route for Prometheus metrics
+	router.Handle("/metrics", promhttp.Handler())
+
 	// Create a handler chain with the request logger
 	chain := http.Handler(logRequest(router))