MQTT client does not connect to MQTT broker after a TCP reconnection

[DiKaY1969]

Hello,

I would like to report a BUG in the MQTT client of the SML reader which means that, for example after restarting the router, no more MQTT data is received from the MQTT broker. The SML reader can be reached via TCP, but the MQTT client no longer establishes the connection to the broker properly after the WLAN reconnects.

A restart of the SMLReader leads to success

Suggestion, simply close the MQTT client after the WLAN reconnects and reconnect if this is not already done?

Thanks in advance.

[DiKaY1969]

Hello,
I use the digitizer (project from https://github.com/jomjol/AI-on-the-edge-device) on an ESP32 - to record the water meter reading and transmit it to home automation.

But this module automatically reconnects to the MQTT broker after rebooting my router after about 2-5 minutes.

It is not necessary to intervene manually.

Maybe you can look at the code and install the same solution there?

Many Thanks.

[mruettgers]

Hey,

Thanks for reporting this issue.
I'll have a look at it next week.

[hamster65]

I ran into this today (again, it happend several times now). I did not look at the code, yet, but for my own projects, I usually do a simple connectivity check (wifi and mqtt) every 10 seconds or so. The libraries provide functions for that. I then either call a "reconnect function" or (if the project does not work without a connection) a esp reset.

[hamster65]

Happend again today after wifi was down because of a router reboot.

I thought I'd try a quick and dirty fix and add publisher.connect(); before yield() in the main loop.
But I cannot compile. Is there anything to set up?

src/main.cpp: In function 'void loop()':
src/main.cpp:117:74: error: 'class std::list<Sensor*>' has no member named 'eplatformio'
for (std::list<Sensor*>::iterator it = sensors->begin(); it != sensors->eplatformio-ide.useBuiltinPIOCorend(); ++it){
^
src/main.cpp:117:86: error: 'ide' was not declared in this scope
for (std::list<Sensor*>::iterator it = sensors->begin(); it != sensors->eplatformio-ide.useBuiltinPIOCorend(); ++it){

[mruettgers]

The problem is that when the connection is lost, the captive portal is activated and IotWebConf (the library I use for WiFi and configuration management) does not reconnect. But this seems to be fixed with the current version of IotWebConf. I will release a new version of SMLReader in the next few days, which will include an update of IotWebConf.

[mruettgers]

I have already released an upgraded version on https://github.com/mruettgers/SMLReader/tree/feature/update-iotwebconf, but haven't had the time to test it thoroughly yet.

You can find a binary compiled with this changes attached, so feel free to test ;-)
SMLReader_v3.0.0_beta.bin.zip

[mruettgers]

Hm. There still seems to be an issue with the PangolinMQTT library not working after a WiFi reconnect (even if I call the connect() method again).

[DiKaY1969]

Sorry, I've been on vacation for a few days.

Possibly you should also execute a disconnect() methode before connect() if it is still connected.

However, the debug output should provide information in our error case.

Thank you for your help.

[mruettgers]

I already tried to use disconnect() during my tests and it didn't change anything.

So I need to debug the third party libs a bit more.

[DiKaY1969]

PangolinMQTT comes with some built-in diagnostics.
These can be controlled by setting the debug level in config.h

/*
Debug levels:
0 - No debug messages
1 - connection / disconnection messages
2 - level 1 + MQTT packet types
3 - level 2 + MQTT packet data
4 - everything
*/

#define PANGO_DEBUG 4

[hamster65]

Going to the http config page and hitting "apply" (after filling out the ap and wifi passwords restores the mqtt connection.

[mruettgers]

Sorry, I did not have the time to look at this issue again yet. But what you say makes sense as the ESP is being rebooted after changing the config.

[stepk71]

I have seen the same problem in my setup using the SMLReader release version.

In my case the device successfully connected to wifi, but the mqtt client did not reconnect. I have noticed in the log of my router that the wifi reconnect took 70 seconds. 30 seconds is the default wifi timeout in IotWebCon v2, afterwards it jumps for 30 seconds into AP mode, before it starts to reconnect.

# define IOTWEBCONF_DEFAULT_WIFI_CONNECTION_TIMEOUT_MS 30000