A minor point:

From the Camel Book (4^th Edition, 2012, page 695), under the heading “Time Efficiency”:

• If you’re deleting characters, tr/abc//d is faster than s/[abc]//g.

So, if speed is a limiting factor, consider replacing:

# Strip out "+" and "/"
$buildID =~ s/\+//g;
$buildID =~ s/\///g;
[download]

with:

$buildID =~ tr{+/}{}d;
[download]

Hope that helps,