I made a program which is saving sensor data in a log file (server site).
This file is stored in a temporary directory (Ram-Disk).
Each line contains a timestamp and a JSON string. 
The update rate is dependent on the sensor data, but the fastest is every 0.5s.
What I want to do is, to stream every update in this file to a client application. 
I have several approaches in mind:

maybe a shared folder on server site (samba) with a script (client site), just checking the file every 0.5s
maybe a another server program running on the server, checking for updates (but this I don't want to do, because Raspberry Pi is slow)

Has anyone maybe done something like this before and can share some ideas? Is there maybe a python module for this already (which opens a file like a stream and if something changed then this stream is giving it out)? Is it smart to check a file constantly for updates?
I'm doing something like that.
I have a server running on my raspberry pi + client that parse the output of the server and sends it to another server on the web.

What I'm doing is that the local server program write it's data in chunks.

Every time it writes the data (by the way, also on tmpfs) it writes it on a different file, so I don't get errors when trying to parse the file while something else is writing to that file..


After it writes the file, it starts the client program in order to parse and send the data (Using subprocess with the name of the file as a parameter).
Works great for me.
Streaming of a log text file with constant updates