tile38/pkg/endpoint/mqtt.go

86 lines
1.4 KiB
Go

package endpoint
import (
"fmt"
"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().SetClientID("tile38").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(),
}
}