importlib

importlib allows you to import a module with the module name being variable.

#!/usr/bin/env python
import os, sys
import importlib

def main():
    fName = '/online_dir/fioAdds.py'
    dirName = os.path.dirname( fName)
    baseName = os.path.basename( fName)

    if baseName.find( '.py') > 0:
        prefixName = baseName.rpartition('.')[0]

    if dirName not in sys.path:
        sys.path.insert( 0, dirName)
    mod = importlib.import_module( prefixName)
    res = mod.main()
    print( res)


if __name__ == "__main__":
    main()