mqttv4 shouldn't die if it cannot connect

[olivluca]

I think that mqttv4 shouldn't die if it cannot connect, but should keep trying.
mqttv4.c does this here

    ret=mqtt_connect();
    if(ret!=0)
        exit(EXIT_FAILURE);

in turn mqtt_connect tries to connect MAX_RETRIES*10 and gives a failure if it cannot connect.
However, if the first connection succeeds, then, even if it's interrupted, it will be retried indefinitely

    while(1)
    {
        mqtt_check_connection();
        mqtt_loop();
        usleep(500*1000);
    }

I think that even the first connection should do the same. My use case is a camera connected to a cellular hotspot, so the connection can be spotty and if there's no connection established when mqttv4 starts it will eventually die.

Maybe it would be enough to just remove the && retries<=(MAX_RETRY*10) conditions from both loops in mqtt_connect (though I'm not sure about the second one calling mosquitto_loop even if the connection failed).

[roleoroleo]

This is a good improvement.
Do you want to make a pr?
This is the repo:
https://github.com/roleoroleo/mqttv4

[olivluca]

Any hint on how to compile just mqttv4? My first attemps have been unsuccessful (the "MStar MSC3XX SDK.zip" I found has no "arm-hisiv300-linux-gcc" command, used in mqttv4 makefile).

[roleoroleo]

hisiv300 is the cross-compiler of the yi-hack-v4 version.
Check the scripts in this folder:
https://github.com/roleoroleo/yi-hack-MStar/tree/master/src/mqtt
Primarily config.mak

[olivluca]

I opened a pull request with a different approach