[Twisted-Python] Twisted.logger on windows max recursion depth exceeded

[Glyph]

Hi John,

Lots of interest in logging this week for some reason :-).

> On Jan 6, 2018, at 4:38 AM, John Aherne <johnaherne at rocs.co.uk <mailto:johnaherne at rocs.co.uk>> wrote:
> 
> If I comment out the print statements all seems to work correctly.
> 
> I assume I am doing something wrong or something I should not be trying to do. But I can't work out what causes the 2 setups to behave so differently.

The issue here is that klein.run() is initializing the (old-style) logging system; that initialization, among other things, includes replacing sys.stdout and sys.stderr with files that will emit log messages rather than write directly.

`print` debugging of log observers is therefore always somewhat risky since many ways of initializing the logging system will do this.

Perhaps the logging system should be a bit more defensive about observers emitting messages; however, for the time being, if you want to do `print` debugging of a log observer, at the top of your file do something like

from sys import stderr as DEBUG

and then everywhere you have a call to the 'print' function, use the 'file' kwarg:

print('ITEM', event[item], file=DEBUG)

I hope this is helpful,

-g
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