Where are CGI script logs written in IIS?

Question

IIS

I am using IIS to run CGI scripts written in python. (namely hgweb.cgi)
But if something goes wrong while executing the script, IIS logs very limited information to the log:

2018-10-20 10:14:52 W3SVC1 ::1 POST /hgweb.cgi/ cmd=unbundle 9000 - ::1 mercurial/proto-1.0+(Mercurial+4.1.3) - localhost:9000 502 2 1 295

Error 502. But what caused it? Most likely the CGI script will output an error to stderr. But where can you see it?

Answer 1

My solution:
https://docs.python.org/2.0/lib/node246.html
I redirected stderr to stdout and put a try catch in the script. It looks like a hack, but it works.