This is a mod that adds a Torch/Flashlight to Minetest ( Github Repo)
Here's how it works
The beam is obstructed by blocks and go through glass and other nodes (with sunlight_propagates = true)
Minetest forumn topic here
I have also added support for technic But since I can't actually edit the mod itself I have provided a file "flashlight.lua" go into your technic mod at mods/technic/technic/tools/ and replace the existing flashlight.lua with the one I have provided then go into the depends.txt and add light_tool