package endpoint import ( "crypto/tls" "crypto/x509" "fmt" "io/ioutil" "sync" "time" paho "github.com/eclipse/paho.mqtt.golang" ) const ( mqttExpiresAfter = time.Second * 30 ) // MQTTConn is an endpoint connection type MQTTConn struct { mu sync.Mutex ep Endpoint conn paho.Client ex bool t time.Time } // Expired returns true if the connection has expired func (conn *MQTTConn) Expired() bool { conn.mu.Lock() defer conn.mu.Unlock() if !conn.ex { if time.Now().Sub(conn.t) > mqttExpiresAfter { conn.close() conn.ex = true } } return conn.ex } func (conn *MQTTConn) close() { if conn.conn != nil { if conn.conn.IsConnected() { conn.conn.Disconnect(250) } conn.conn = nil } } // Send sends a message func (conn *MQTTConn) Send(msg string) error { conn.mu.Lock() defer conn.mu.Unlock() if conn.ex { return errExpired } conn.t = time.Now() if conn.conn == nil { uri := fmt.Sprintf("tcp://%s:%d", conn.ep.MQTT.Host, conn.ep.MQTT.Port) ops := paho.NewClientOptions() if conn.ep.MQTT.CertFile != "" || conn.ep.MQTT.KeyFile != "" || conn.ep.MQTT.CACertFile != "" { var config tls.Config if conn.ep.MQTT.CertFile != "" || conn.ep.MQTT.KeyFile != "" { cert, err := tls.LoadX509KeyPair(conn.ep.MQTT.CertFile, conn.ep.MQTT.KeyFile) if err != nil { return err } config.Certificates = append(config.Certificates, cert) } if conn.ep.MQTT.CACertFile != "" { // Load CA cert caCert, err := ioutil.ReadFile(conn.ep.MQTT.CACertFile) if err != nil { return err } caCertPool := x509.NewCertPool() caCertPool.AppendCertsFromPEM(caCert) config.RootCAs = caCertPool } ops = ops.SetTLSConfig(&config) } nano := time.Now().UnixNano() clientID := fmt.Sprintf("tile38_%x", nano) //the id of connected clients should be unique ops = ops.SetClientID(clientID).AddBroker(uri) c := paho.NewClient(ops) if token := c.Connect(); token.Wait() && token.Error() != nil { return token.Error() } conn.conn = c } t := conn.conn.Publish(conn.ep.MQTT.QueueName, conn.ep.MQTT.Qos, conn.ep.MQTT.Retained, msg) t.Wait() if t.Error() != nil { conn.close() return t.Error() } return nil } func newMQTTConn(ep Endpoint) *MQTTConn { return &MQTTConn{ ep: ep, t: time.Now(), } }