ideas on how to make logging more flexible

[pljakobs]

Sming logging is, as far as I can tell, entirely based around the Serial device.
Since most devices are probably not connected to a serial terminal, that might not always be ideal.
Tasmota, as an example, supports udp Syslog, file Log and a few more. Much of Sming's logging is, as far as I can see, compile time (like setting the loglevel to print)
I have looked into it a bit and my thoughs were:
we could have a Stream class that accepts writes and sends it to a number of (runtime configurable) Streams which could be Serial or any other stream and use that as the target for m_setPuts
as receiver streams, it would be great to have streams sending to remote Syslog, websocket (that might already be possible) and a limited size file that circularly overwrites older content.
I'm not really sure about the latter, as it would potentially put a lot of write load on the flash chip.
This last part might already be possible using DataLog.
I have had issues in the past where users reported bugs but since they could not provide logs, I was not really able to understand what was going on on their end.

Ideally, but I think this would be more difficult to do, the log level could be set separately for every output stream such that writing to file would not be too overwhelming while, for example, writing to rsyslog could be much more verbose

I hope I have not overlooked something and wonder if it's worth working on this.

[mikee47]

Sample applications and test code does tend to use Serial but the framework uses debug_x for debug output. This be redirected using a m_setPuts call. See HardwareSerial::systemDebugOutput for example.

If you want all debug output sent to a particular stream you can do something like this:

Print* dbgout; ///< Set this as required, e.g. to `&Serial` or wherever.

size_t debugWrite(const char* buffer, size_t length)
{
  return dbgout->write(buffer, length);
}

void init()
{
  dbgout = &Serial; // For example
  m_setPuts(debugWrite);
}

Within your application you can use dbgout or debug_x or m_printf(...) as required and they'll all be directed to the same place.

NB. The Serial definition itself is a HardwareSerial instance and you can change the serial port it uses, but it cannot be changed to some other stream type.