This is an LED diffuser tube designed to slide snugly over a commonly available metal channel from a hardware store (20mm wide by 16mm deep), which has had an LED strip stuck down inside of it.

Printed vertically with standard White PLA+

I increased layer height to 0.4mm for this print, and you must print with a brim, and it may be worth increasing the line count of the brim (8mm/30 worked for me) since there isn't much material touching the build plate.

These are 0.25m tall, so work out how many you'll need depending on how many meters you're trying to cover, and you should be able to duplicate and just print them all at once.