+1 on fixing it parse_and_plot_single_metrics(). 
We also need to support a combination of local and http. 
so the user still uses -i , but no "access".  Then inside parse_and_plot_single_metrics(), it will handle the 2 cases correctly. 
if it is a http:// or https://, it does not path_join with input_dir. 
Otherwise, it path_join. 
Then in collect(), simply handle two clean cases of : (1) absolute local path; (2) a complete url