Alarm Data caused Weewx to exit due to NULL rainfall

[mike.t...@noworries.plus.com]

Weewx version 4.10 running on RPI 4 using FO weather station. 

Last change was 2 weeks ago when weather station reported crazy rain volume and rain rate. I amended the alarm condition from;

badData_test = outTemp is None or outTemp < 10.0 or windGust is None or windGust > 100

to

 badData_test = outTemp is None or outTemp < 10.0 or windGust is None or windGust > 100 or rain > 10 or rainRate > 100

Weewx last ran successfully at 00:55 30 August and aborted with the following 

Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__: Caught unrecoverable exception:
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****  '>' not supported between instances of 'NoneType' and 'int'
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****  Traceback (most recent call last):
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****    File "/home/weewx/bin/weewx/engine.py", line 214, in run
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****      self.dispatchEvent(weewx.Event(weewx.CHECK_LOOP, packet=packet))
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****    File "/home/weewx/bin/weewx/engine.py", line 245, in dispatchEvent
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****      callback(event)
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****    File "/home/weewx/bin/weewx/engine.py", line 634, in check_loop
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****      raise BreakLoop
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****  weewx.engine.BreakLoop
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****  During handling of the above exception, another exception occurred:
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****  Traceback (most recent call last):
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****    File "/home/weewx/bin/weewxd", line 154, in main
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****      engine.run()
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****    File "/home/weewx/bin/weewx/engine.py", line 221, in run
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****      self.dispatchEvent(weewx.Event(weewx.POST_LOOP))
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****    File "/home/weewx/bin/weewx/engine.py", line 245, in dispatchEvent
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****      callback(event)
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****    File "/home/weewx/bin/weewx/engine.py", line 644, in post_loop
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****      self._software_catchup()
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****    File "/home/weewx/bin/weewx/engine.py", line 717, in _software_catchup
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****      origin='software'))
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****    File "/home/weewx/bin/weewx/engine.py", line 245, in dispatchEvent
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****      callback(event)
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****    File "/home/weewx/bin/user/badData.py", line 94, in newArchiveRecord
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****      if eval(self.expression, None, record):                       # NOTE 2
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****    File "<string>", line 1, in <module>
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****  TypeError: '>' not supported between instances of 'NoneType' and 'int'
Aug 30 01:05:16 weepi weewx[6744] CRITICAL __main__:     ****  Exiting.

I've checked the database and sure enough there are 5 entries from 01:05 to 03:07 in the archive table where rain is NULL. I was not expecting rain to ever be NULL. Checking the database there are 909 occurrences over the last 10 years where rain is NULL. Also looking at other columns such as outtemp there are NULL occurrences as well.

Also I'm not sure about TypeError: '>' not supported between instances of 'NoneType' and 'int'. Which seems to imply that the > character is the issue. However if condition statement is incorrect I would expect it to fail every time it runs.   

snippet from badData.py (I copied the alarm example many years back)

    def newArchiveRecord(self, event):
        """Gets called on a new archive record event."""

        # Get the new archive record:
        record = event.record
        # Evaluate the expression in the context of the event archive record.
        # Sound the alarm if it evaluates true:
        if eval(self.expression, None, record):                       # NOTE 2
            # Sound the alarm!
            # Launch in a separate thread so it doesn't block the main LOOP thread:
            t  = threading.Thread(target = MyBadData.soundTheAlarm, args=(self, record))
            t.start()
            # Record when the message went out:
            self.last_msg_ts = time.time()

Reverting the alarm condition to remove rain check, WEEWX successfully ran as you'd expect.

I then put the rain alarm condition back in and weewx ran successfully again as expected.

My Python skills are pretty basic hence my query is how can I trap this NULL condition?

[mike.t...@noworries.plus.com]

Is it just a matter of checking for None first i.e.

 badData_test = outTemp is None or outTemp < 10.0 or windGust is None or windGust > 100 or rain is None or rain > 10 or rainRate is None or rainRate > 100