refactor and cleanup

mqtt/mqtt.go

@@ -0,0 +1,103 @@
+package mqtt
+
+import (
+	"crypto/tls"
+	"errors"
+	"log"
+	"time"
+
+	MQTT "github.com/eclipse/paho.mqtt.golang"
+)
+
+type Config struct {
+	Server   string
+	ClientID string
+	Username string
+	Password string
+}
+
+type Client struct {
+	client MQTT.Client
+	ID     int
+	closed bool
+}
+
+var ErrNotConnected = errors.New("MQTT client not connected")
+
+func New(config *Config) *Client {
+	m := &Client{}
+
+	connOpts := MQTT.NewClientOptions().
+		AddBroker(config.Server).
+		SetClientID(config.ClientID).
+		SetCleanSession(true).
+		SetAutoReconnect(false)
+
+	if config.Username != "" {
+		connOpts.SetUsername(config.Username)
+		if config.Password != "" {
+			connOpts.SetPassword(config.Password)
+		}
+	}
+
+	tlsConfig := &tls.Config{InsecureSkipVerify: true, ClientAuth: tls.NoClientCert}
+	connOpts.SetTLSConfig(tlsConfig)
+
+	connOpts.OnConnectionLost = func(c MQTT.Client, err error) {
+		log.Printf("MQTT disconnected: %s\n", err)
+	}
+
+	connect := func() {
+		log.Printf("Trying to connect to MQTT %s ...\n", config.Server)
+		newClient := MQTT.NewClient(connOpts)
+		token := newClient.Connect()
+		token.Wait()
+		if token.Error() == nil {
+			m.client = newClient
+			m.ID++
+			log.Printf("Connected to MQTT. Session ID %d\n", m.ID)
+		}
+	}
+
+	connect()
+	go func() {
+		ticker := time.NewTicker(5 * time.Second)
+		for range ticker.C {
+			if m.closed {
+				return
+			}
+			if m.client == nil || !m.client.IsConnectionOpen() {
+				connect()
+			}
+		}
+		if m.client != nil {
+			m.client.Disconnect(100)
+		}
+	}()
+	return m
+}
+
+func (m *Client) Publish(topic string, qos byte, retained bool, payload string) error {
+	if m.client == nil {
+		return ErrNotConnected
+	}
+	token := m.client.Publish(topic, qos, retained, payload)
+	token.Wait()
+	return token.Error()
+}
+
+func (m *Client) Subscribe(topic string, callback func(message string)) error {
+	if m.client == nil {
+		return ErrNotConnected
+	}
+	token := m.client.Subscribe(topic, 0, func(c MQTT.Client, m MQTT.Message) {
+		callback(string(m.Payload()))
+	})
+	token.Wait()
+	return token.Error()
+}
+
+func (m *Client) Close() error {
+	m.closed = true
+	return nil
+}