My coding error in a function doesn't indicate it's a coding error

I’m opening this issue in the hopes of helping future novices. mqttwarn 0.10.4

I was amending a functions file today and when I got the field names wrong, I got a warning:

2019-01-19 16:11:36,751 WARNING [mqttwarn] Cannot invoke filter function logging_filter defined in logging/hare: 'rhostname'

I had:

if data['rhostname'] ==  'foo'     and data['host'] in ['bar', ...]

I had copy pasted and tried to reverse the fields. This is what I needed:

if data['rhost'] ==  'foo'     and data['hostname'] in ['bar', ...]

I interpreted the message as: cannot invoke this function … because I can’t find it. But wait, … it’s right there, what’s going on?

I didn’t realize it was more like a syntax error or a field which mqttwarn could not access.

Yes, I see now that ‘rhostname’ is mentioned in the message, but that didn’t help me understand that I was “doing it wrong”. I was chasing the wrong thing.

Thank you.

[jpmens]

I will add a note to the documentation.

[jpmens]

Nothing can help you find logical errors: Consider

a = 1
a = a + 3

but you wanted to add 2… Exaggerated but I’m trying to prove a point.