Create an MQTT client plugin

plugins/mqttclient/mqtt.go

@@ -0,0 +1,71 @@
+package mqttclient
+
+import (
+	"encoding/json"
+	"fmt"
+	"time"
+
+	"github.com/diebietse/invertergui/mk2driver"
+	mqtt "github.com/eclipse/paho.mqtt.golang"
+)
+
+const keepAlive = 5 * time.Second
+
+// Config sets MQTT client configuration
+type Config struct {
+	Broker   string
+	ClientID string
+	Topic    string
+	Username string
+	Password string
+}
+
+// New creates an MQTT client that starts publishing MK2 data as it is received.
+func New(mk2 mk2driver.Mk2, config Config) error {
+	c := mqtt.NewClient(getOpts(config))
+	if token := c.Connect(); token.Wait() && token.Error() != nil {
+		return token.Error()
+	}
+
+	go func() {
+		for e := range mk2.C() {
+			if e.Valid {
+				data, err := json.Marshal(e)
+				if err != nil {
+					fmt.Printf("Data error: %v\n", err)
+					continue
+				}
+
+				t := c.Publish(config.Topic, 0, false, data)
+				t.Wait()
+				if t.Error() != nil {
+					fmt.Printf("Error: %v\n", t.Error())
+				}
+			}
+		}
+	}()
+	return nil
+}
+
+func getOpts(config Config) *mqtt.ClientOptions {
+	opts := mqtt.NewClientOptions()
+	opts.AddBroker(config.Broker)
+	opts.SetClientID(config.ClientID)
+
+	if config.Username != "" {
+		opts.SetUsername(config.Username)
+	}
+	if config.Password != "" {
+		opts.SetPassword(config.Password)
+	}
+	opts.SetKeepAlive(keepAlive)
+
+	opts.SetOnConnectHandler(func(mqtt.Client) {
+		fmt.Print("Client connected to broker")
+	})
+	opts.SetConnectionLostHandler(func(cli mqtt.Client, err error) {
+		fmt.Printf("Client connection to broker losted: %v", err)
+
+	})
+	return opts
+}