Files
lambdaiot-core/internal/mqtt/mqtt.go
T

91 lines
2.1 KiB
Go

package mqtt
import (
"fmt"
"time"
"git.piskot.si/SeminarM2/lambdaiot-core/internal/config"
paho "github.com/eclipse/paho.mqtt.golang"
)
type Client struct {
client paho.Client
}
// Default is a package-level client used by helpers
var Default *Client
// SetDefault sets the package default client
func SetDefault(c *Client) {
Default = c
}
// PublishDefault publishes using the default client
func PublishDefault(topic string, payload []byte) error {
if Default == nil {
return fmt.Errorf("no default mqtt client")
}
return Default.Publish(topic, payload)
}
func Connect(cfg config.MQTTConfig) (*Client, error) {
opts := paho.NewClientOptions()
opts.AddBroker(cfg.Broker)
if cfg.ClientID != "" {
opts.SetClientID(cfg.ClientID)
}
if cfg.Username != "" {
opts.SetUsername(cfg.Username)
opts.SetPassword(cfg.Password)
}
opts.SetAutoReconnect(true)
opts.SetConnectRetry(true)
opts.SetConnectTimeout(5 * time.Second)
c := paho.NewClient(opts)
token := c.Connect()
if ok := token.WaitTimeout(10 * time.Second); !ok {
return nil, fmt.Errorf("mqtt connect timeout")
}
if err := token.Error(); err != nil {
return nil, err
}
return &Client{client: c}, nil
}
func (c *Client) Publish(topic string, payload []byte) error {
if c == nil || c.client == nil {
return fmt.Errorf("mqtt client not connected")
}
token := c.client.Publish(topic, 0, false, payload)
if ok := token.WaitTimeout(5 * time.Second); !ok {
return fmt.Errorf("publish timeout")
}
return token.Error()
}
// Subscribe subscribes to the given topic and calls the provided handler
// for each incoming message.
func (c *Client) Subscribe(topic string, handler func(topic string, payload []byte)) error {
if c == nil || c.client == nil {
return fmt.Errorf("mqtt client not connected")
}
mh := func(cli paho.Client, msg paho.Message) {
if handler != nil {
handler(msg.Topic(), msg.Payload())
}
}
token := c.client.Subscribe(topic, 0, mh)
if ok := token.WaitTimeout(5 * time.Second); !ok {
return fmt.Errorf("subscribe timeout")
}
return token.Error()
}
func (c *Client) Close() {
if c == nil || c.client == nil {
return
}
c.client.Disconnect(250)
}