feat: move example to its package

example/cli/internal/cmd/subscribe/main.go

@@ -0,0 +1,85 @@
+package subscribe
+
+import (
+	"os"
+	"os/signal"
+	"syscall"
+
+	mqtt "github.com/eclipse/paho.mqtt.golang"
+	"github.com/pterm/pterm"
+	"github.com/snapp-incubator/pakhshi/pkg/client"
+	"github.com/spf13/cobra"
+)
+
+const (
+	// TopicFlag used with cobra to read the topic flag from user.
+	TopicFlag = "topic"
+	// QoSFlag used with cobra to read the qos flag from user.
+	QoSFlag = "qos"
+
+	// Timeout for disconnecting from brokers.
+	Timeout = 10
+)
+
+type Config struct {
+	Brokers []string
+	QoS     byte
+	Topic   string
+}
+
+func main(cfg Config) {
+	opts := mqtt.NewClientOptions()
+
+	for _, broker := range cfg.Brokers {
+		opts.AddBroker(broker)
+	}
+
+	c := client.NewClient(opts)
+
+	if token := c.Connect(); token.Wait() && token.Error() != nil {
+		pterm.Error.Println("mqtt connection failed:", token.Error().Error())
+
+		return
+	}
+
+	pterm.Info.Printf("subscribing on %s\n", cfg.Topic)
+
+	if token := c.Subscribe(cfg.Topic, cfg.QoS, func(c mqtt.Client, m mqtt.Message) {
+		pterm.Info.Printf("received: %s\n", string(m.Payload()))
+	}); token.Wait() && token.Error() != nil {
+		pterm.Error.Println("mqtt subcription failed:", token.Error().Error())
+
+		return
+	}
+
+	quit := make(chan os.Signal, 1)
+	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
+	<-quit
+
+	c.Disconnect(Timeout)
+}
+
+// Register migrate command.
+func Register(root *cobra.Command, brokers *[]string) {
+	// nolint: exhaustivestruct
+	cmd :=
+		&cobra.Command{
+			Use:   "subscribe",
+			Short: "subscribe on multiple brokers at the same time",
+			Run: func(cmd *cobra.Command, args []string) {
+				qos, _ := cmd.Flags().GetInt8(QoSFlag)
+				topic, _ := cmd.Flags().GetString(TopicFlag)
+
+				cfg := Config{
+					Brokers: *brokers,
+					QoS:     byte(qos),
+					Topic:   topic,
+				}
+
+				main(cfg)
+			},
+		}
+	cmd.Flags().StringP(TopicFlag, "t", "hello", "topic to subscribe on")
+	cmd.Flags().Int8P(QoSFlag, "q", 0, "subscription qos")
+	root.AddCommand(cmd)
+}