Feature Request: write a log file

[Reissner]

I consider pythontex quite mature already (version 0.18) and also quite important and almost in one line with bibtex, makeindex
and makeglossaries.
Also the way pythontex is used is comparable: first run lualatex or what,
then run those auxiliary programs and finally lualatex again, maybe several times to get the output pdf right.

There is one respect, in which pythontex is not on one line with the other auxiliary programs:
It does not write (at the moment) a log file.
Instead it outputs warnings and errors on stdout or errout.
There are many build tools for latex.
I myself wrote a maven plugin to create all my pdf out of latex.
It is sensitive to log files to detect not only errors (which can be done by return code),
but also warnings, and those by scanning the log files.

For pythontex I helped myself by writing a wrapper leading the output into a log file with ending plg.
This I read and detect errors and even warnings.
My aim is to guarantee perfect output if I can compile without error or warning. _