use the CI to generate the pdf from the tex source. pdflatex is run two times, the first time ignoring the errors and the second time checking the errors. 
for that, a small python script 'errcheck_pdflatex_log.py' was written, such that the pdflatex can be run in batchmode, and the python script checks then the log output for errors and warnings, and prints them. It has the parameter ignore_errors = 0/1.