Using threads to show progress

Ruby
21

hmm…yes thats right. Did not think it through. Using queue may not be a
good idea after all as you pointed out. After all queues are meant for
asynchronous stuff and real time status update doesn’t actually fit into
that :slight_smile:

So is using two threads is the best solution ?

22

On Thursday 17 December 2009 11:51:10 am Piyush R. wrote:

So is using two threads is the best solution ?

It depends what you mean by “best”.

The simplest solution, and hardest to get wrong, would be something like
this:

desc “Go through dictated exams and show IDs”
task(:showSomeIDs => :environment) do
interval = 0.1
last_update = 0
DictatedExam.all.each do |exam|
if Time.now - last_update >= interval
puts exam.id
last_update = Time.now
end
end
end

No threads involved at all. However, this has the problem that you could
have
several items take much faster than that interval to process, and then
one
takes a very long time – in which case, the display would stop updating
(which is good), but it would currently show the wrong id, not the id
which is
taking so long.

I don’t know that this matters in this case, but if you did want a more
accurate update, you’d probably want some sort of thread. But I’d hide
that
thread in a library, and I might not have it always poll.