MQTT Socket error after 4 consecutive MQTT connect/disconnect

Question

Hi, 
 we are using MQTT to push the sensor and GPS data with 1 hour interval. After 4 consecutive connect and disconnect, MQTT is returning socket error. It requires the device reboot to connect again, so rebooting the device after every 4 MQTT connections. Because of reboot the device is taking longer time to get GPS fix for first time. 
 It is 100% reproducible. we are using our own MQTT broker and also tried the other brokers as well and behavior is same. 
 Error log returned by MQTT is "ERROR: mqtt_connect -12". 
 Please help us to resolve the issue.

Didrik Rokhaug · Accepted Answer

Turns out it is easier than I thought. 
 You need to call mqtt_live() after mqtt_disconnect() for the mqtt library to close the socket. 
 If not, you will run out of sockets, and get ENOMEM (-12).

Balamurugan · Answer

Interesting!! 
 Tested with the changes as you mentioned and MQTT working as expected after consecutive MQTT connect/disconnect 
 printk("Disconnecting MQTT client...
"); err = mqtt_disconnect(&client); if (err) { printk("Could not disconnect MQTT client. Error: %d
", err); } err = mqtt_live(&client); if (err != 0) { printk("ERROR: mqtt_live %d
", err); } 
 Thanks for your support.

MQTT Socket error after 4 consecutive MQTT connect/disconnect

Top Replies