@dennix sounds like you're going to be stuck with hacky workarounds, unless "show log" accepts flags to say "please don't page the output" or the like.
i've not used telnetlib, but if you can accept it taking a while, you could use either read_until or expect and look for the device's prompt. if it times out, send whichever key the device uses to fetch another page, and call read_until/expect again.
@dennix if it's not a huge pain on the device, that'll probably turn out to be much easier on the python side. requests is your friend here.
@rascalking Thanks for taking the time to respond :)
Basically, that works. But it seems the device isn't so happy with someone asking so fast and some output is missing. To avoid more workarounds, I think I'll try to get my log via http. :(