First commit

.gitignore

@@ -0,0 +1,5 @@
+/mqtt-sounder
+/mqtt-sounder.exe
+/.vscode
+/sounds
+/config.yaml

README.md

@@ -0,0 +1,68 @@
+# MQTT sounder
+
+Simple mqtt command executor to play sounds.
+
+Config example:
+
+```yaml
+mqtt:
+  address: "tcp://example.com:1883"
+  username: "mqtt"
+  password: "${MQTT_PASSWORD}"
+  client_id: "mqtt_sounder"
+  command_topic: "notify/sounder/command"
+  state_topic: "notify/sounder/state"
+player:
+  default_program: ffplay
+  default_args:
+    - "-autoexit"
+    - "-nodisp"
+    - "-loglevel"
+    - "quiet"
+  sounds:
+    test:
+      args: ["sounds/test.mp3"] # args appended to default_args
+    doorbell:
+      args: ["sounds/doorbell.wav"]
+
+    # default:
+    #   program: bash # default_program replaced to program
+    #   args:  # default_args replaced to args because program specified
+    #     - "-c"
+    #     - "echo sound not found"
+
+    # default:
+    #   args:
+    #     - "sounds/{payload}.mp3" # {payload} replaced to command payload, use only in trusted environment
+
+```
+
+Password is provided via **MQTT_PASSWORD** environment variable.
+
+Usage:
+
+```
+mqtt-sounder config.yaml
+```
+
+Systemd unit example:
+
+```ini
+[Unit]
+Description=Play sound via mqtt commands
+After=network-online.target
+StartLimitIntervalSec=500
+StartLimitBurst=5
+
+[Service]
+Type=simple
+User=mqtt_sounder
+Environment=MQTT_PASSWORD=xxxxxxxxxxxxx
+WorkingDirectory=/opt/mqtt-sounder/
+ExecStart=/opt/mqtt-sounder/mqtt-sounder config.yaml
+Restart=on-failure
+RestartSec=5s
+
+[Install]
+WantedBy=multi-user.target
+```

go.mod

@@ -0,0 +1,11 @@
+module mqtt-sounder
+
+go 1.19
+
+require (
+	github.com/eclipse/paho.mqtt.golang v1.4.3 // indirect
+	github.com/gorilla/websocket v1.5.0 // indirect
+	golang.org/x/net v0.8.0 // indirect
+	golang.org/x/sync v0.1.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -0,0 +1,11 @@
+github.com/eclipse/paho.mqtt.golang v1.4.3 h1:2kwcUGn8seMUfWndX0hGbvH8r7crgcJguQNCyp70xik=
+github.com/eclipse/paho.mqtt.golang v1.4.3/go.mod h1:CSYvoAlsMkhYOXh/oKyxa8EcBci6dVkLCbo5tTC1RIE=
+github.com/gorilla/websocket v1.5.0 h1:PPwGk2jz7EePpoHN/+ClbZu8SPxiqlu12wZP/3sWmnc=
+github.com/gorilla/websocket v1.5.0/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
+golang.org/x/net v0.8.0 h1:Zrh2ngAOFYneWTAIAPethzeaQLuHwhuBkuV6ZiRnUaQ=
+golang.org/x/net v0.8.0/go.mod h1:QVkue5JL9kW//ek3r6jTKnTFis1tRmNAW2P1shuFdJc=
+golang.org/x/sync v0.1.0 h1:wsuoTGHzEhffawBOhz5CYhcrV4IdKZbEyZjBMuTp12o=
+golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

main.go

@@ -0,0 +1,127 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"os/signal"
+	"strings"
+	"syscall"
+
+	mqtt "github.com/eclipse/paho.mqtt.golang"
+	"gopkg.in/yaml.v3"
+)
+
+var config = Config{}
+
+var onCommandMessage mqtt.MessageHandler = func(client mqtt.Client, msg mqtt.Message) {
+	value := string(msg.Payload())
+
+	fmt.Printf("Requested %s\n", value)
+
+	soundDef, found := config.Player.Sounds[value]
+
+	if !found {
+		soundDef, found = config.Player.Sounds["default"]
+		if !found {
+			fmt.Fprintf(os.Stderr, "No config entry found\n")
+			return
+		}
+	}
+
+	token := client.Publish(config.Mqtt.StateTopic, 0, false, "playing")
+	token.Wait()
+
+	var args []string
+	var program string
+
+	if soundDef.Program == "" {
+		program = config.Player.DefaultProgram
+
+		args = make([]string, len(config.Player.DefaultArgs))
+		copy(args, config.Player.DefaultArgs)
+
+		args = append(args, soundDef.Args...)
+	} else {
+		program = soundDef.Program
+		args = make([]string, len(soundDef.Args))
+		copy(args, soundDef.Args)
+	}
+
+	for i := range args {
+		args[i] = strings.ReplaceAll(args[i], "{payload}", value)
+	}
+
+	fmt.Printf("Running %v %v\n", program, args)
+	cmd := exec.Command(program, args...)
+	cmd.Stderr = os.Stderr
+
+	stdout, err := cmd.Output()
+
+	out := strings.TrimSpace(string(stdout))
+
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Execution error: %v\n", err.Error())
+	}
+
+	if out != "" {
+		fmt.Printf("Command output: %s\n", out)
+	}
+
+	token = client.Publish(config.Mqtt.StateTopic, 0, false, "stopped")
+	token.Wait()
+}
+
+var onConnected mqtt.OnConnectHandler = func(client mqtt.Client) {
+	fmt.Println("Connected")
+
+	token := client.Subscribe(config.Mqtt.CommandTopic, 1, onCommandMessage)
+	token.Wait()
+}
+
+var onDisconnected mqtt.ConnectionLostHandler = func(client mqtt.Client, err error) {
+	fmt.Fprintf(os.Stderr, "Connection lost: %v\n", err)
+}
+
+func main() {
+	if len(os.Args) < 2 {
+		fmt.Fprintf(os.Stderr, "Usage: %s config.yaml\n", os.Args[0])
+		os.Exit(2)
+	}
+
+	yamlData, err := os.ReadFile(os.Args[1])
+
+	if err != nil {
+		panic(err.Error())
+	}
+
+	yamlStr := os.ExpandEnv(string(yamlData))
+	err = yaml.Unmarshal([]byte(yamlStr), &config)
+
+	if err != nil {
+		panic(err.Error())
+	}
+
+	opts := mqtt.NewClientOptions()
+	opts.AddBroker(config.Mqtt.Address)
+	opts.SetClientID(config.Mqtt.ClientId)
+	opts.SetUsername(config.Mqtt.Username)
+	opts.SetPassword(config.Mqtt.Password)
+	opts.SetAutoReconnect(true)
+
+	opts.OnConnect = onConnected
+	opts.OnConnectionLost = onDisconnected
+	client := mqtt.NewClient(opts)
+
+	if token := client.Connect(); token.Wait() && token.Error() != nil {
+		panic(token.Error())
+	}
+
+	// wait forever for interrupt
+	exit := make(chan os.Signal, 1)
+	defer close(exit)
+	signal.Notify(exit, syscall.SIGINT, syscall.SIGTERM)
+	<-exit
+
+	client.Disconnect(250)
+}

structs.go

@@ -0,0 +1,26 @@
+package main
+
+type MqttConfig struct {
+	Address      string
+	Username     string
+	Password     string
+	CommandTopic string `yaml:"command_topic"`
+	StateTopic   string `yaml:"state_topic"`
+	ClientId     string `yaml:"client_id"`
+}
+
+type SoundConfig struct {
+	Program string
+	Args    []string `yaml:",flow"`
+}
+
+type PlayerConfig struct {
+	DefaultProgram string   `yaml:"default_program"`
+	DefaultArgs    []string `yaml:"default_args,flow"`
+	Sounds         map[string]SoundConfig
+}
+
+type Config struct {
+	Mqtt   MqttConfig
+	Player PlayerConfig
+}