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knolleary
Time out in Connect() Function
The connect() Function is a blocking Function, i want it as short as possible. For that i have set MQTT_SOCKET_TIMEOUT = 5 SEC, But in my case, timeout in connection usually takes around 30 sec in a low network area. I am unable to find out any other timeout in the source code. Please help me how can i set this time out to exactly 5 seconds. No issues if there is any delay due to network but i want to get out of this function in exactly 5 seconds. Setting MQTT_SOCKET_TIMEOUT = 5 SEC doesn't seems to solve my purpose
I have the same problem .. on poor network connectivity client->write might hang a long time and after it gets back I get a bunch of subscribed messages at once and then a hangup .. ~32seconds in my case.
I lowered both timeouts to 5seconds as well and also tried to add:
_client->setTimeout(500);
in the connection function .. no change.
To test low connectivity I slightly touch the esp8266 .. then the _client->write function just fails with D: prepare client->write | D: client->write rc = 22 len = 42 indicating it has written 22 of 42 bytes .. the problem might be more with the underlying wificlient ..
Before including PubSubClient.h, define MQTT_SOCKET_TIMEOUT in seconds.
So to set a 1 second timeout: #define MQTT_SOCKET_TIMEOUT 1 #include <PubSubClient.h>
@fusionstream that won't work in the Arduino IDE. It moves all includes to the top before compiling.
If you are using AVR and Wiznet libraries, use setRetransmissionCount() and set it to 4 (default is 8) on init. I tested this on W5500. I got that problem when connection was corrupt - wiznet was hanging in a retransmittion loop and it caused my watchdog to run out and restart the AVR. It took something around 20-30 seconds. Now it fits the 8s watchdog and works fine.
Hello,
i am still facing the same issue with latest version of the library. Anybody found any luck with this question.
@knolleary: Would be greatful for any hint here. Even with latest lirbary (2.8.0) no luck with changing the timeouts. Tried both the ways of #define MQTT_SOCKET_TIMEOUT 5 and setSocketTimeout(5) no change with both. Is this somehow hardcoded ?
Thanks in advance!
Not sure, whether this is exact solution to your problem, but I also faced such problem by working with this library for the first time.
My esp32 connects to my mobile hotspot with mobile data turned on; messages are sent successfully. Then, I turned off mobile data to test the behavior of my program, but esp32 is still connected to hotspot. By looking at Serial output in Arduino IDE, I noticed that a call to "connect(mqtt_station, mqtt_username, mqtt_password)" took 20 seconds.
Here are the screenshots:
I found that problem is in select function from socket programming: https://man7.org/linux/man-pages/man2/select.2.html
Since I pass WifiClient object to PubSubClient, it calls its own connect method where select() does its work.
It passes only two argument, since third argument 'timeout' is not allowed - PubSubClient stores pointer to abstract class Client as its attribute, which only has declarations of 'connect()' function with two arguments.
Therefore, as can be seen from screenshot, -1 is passed implicitly, which does all the 'magic'.
And according to the link I provided to Linux man-page:
If timeout is specified as NULL, select() blocks indefinitely waiting for a file descriptor to become ready.
So, you need to just pass your timeout parameter in milliseconds, as I did (2000ms):
Now, in Serial it shows different disconnect reason:
Hello everyone! I use WiFiClientSecure.h. If the connection is lost (namely, the Internet connection, not wifi), then the esp32 board freezes for a long time. And if the board starts in this mode, with inaccessible internet, then nothing hangs. I reduced the timeouts in the library to 1 second and call "client connect" every 10 seconds. It's clumsy, but at least it's something. Help me please.
