I would go for the global variable, but hidden behind a
module which will not export it by default. You could call
this variable a "framework global", and is also a singleton.
package MyFramework;
use strict;
use Exporter;
use vars qw(@ISA @EXPORT @EXPORT_OK);
@ISA = qw(Exporter);
@EXPORT_OK = qw( $HANDLE );
1;
Thus, whenever you need to use it in a module, you'll
just have to put:
use MyFramework qw ( $HANDLE );
at the top of it and it'll be available for all methods in
that module. Where would you initialize this variable? As
early as possible, before any method requiring it is
executed, preferrably in a BEGIN block within the
MyFramework package itself.
This approach is equivalent to your "get_handle" method
because it ensures that the same instance will be used by
all. It also makes it easy to replace the class that
produces the handle, because it would only be invoked once in
the whole of your code, at the place where $HANDLE is
initialized.