From: Robert Klemme <shortcutter@...>
Date: 2011-06-16T16:07:18+09:00
Subject: Re: queues? inotify? anything else?

On Wed, Jun 15, 2011 at 11:58 PM, Matt Harrison
<iwasinnamuknow@genestate.com> wrote:
> I don't even really know how to describe this problem. I know what I want
> the end result to be, but I've run into a dead end trying to figure out
> possible solutions.
>
> I've got a script which looks for files of a given type in a directory,
> processes them, then moves the result elsewhere and removes the sources.
>
> Currently, if I add another file to the directory while the script is
> running, it will not be noticed (I'm using a simple directory read).
>
> I would like to be able to add file while the script is busy and have it
> append the new filename to its list. I've considered inotify type monitoring
> but I don't know much about it and if it could be made to fit this
> single-threaded script.
>
> I've also thought about re-reading the directory after each file operation
> is complete, and adding the previously unknown filenames to the list.

In this case you would need to keep track of all files seen already so
you do not add files multiple times.

> I'm just not sure which way I should begin looking, if there's a good
> solution for this already out there, or...what.
>
> Thanks for some input

Since your script is single threaded anyway and if you do not want to
change too much you could simply wrap your whole script in a loop
which is terminated if the reading of the directory does not find any
matching files any more, e.g.

files = nil

until (files = find_files).empty?
  files.each do |f|
    process f
    move v
  end
end

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/