Applications / code security
If your logs are stored in a commong log folder, then a simple solution would be to have proper naming for logs of different applications
e.g.

pythonApp_log_timestamp
aspNetApp_log_timestamp

This way applications will write to its designated logs and not overwrite other application's log and would work irrespective of your hosting environment linux or windows.
Also you could limit the file size of each of the log file that your applications create, this way you could ensure that applications create new file if specified file size has been reached and not too much data is dumped into a single file, this will help in debugging or verifying the logs later. 
I use this method in my application and helps me find the log from specific duration and not searching logs too much.
I have a 5 applications(programmed in 5 different languages) deployed in one common web server and these applications are written to work on a particular task and create a log file for any action. How can we achieve a security of log file by not being over written by other applications?