Q:

Log with % resources used on python script

What is it the best way to create a log that resume the percentage of resources (ram, cpu ...) used in each execution of python script. 

A:

I think the resource library and the getrusage function is the solution you're looking for, but it will only inform you of the memory used, not the cpu. 
Other option is execute a unix command like perf through a bash script and save the results.