Where to put Settings-Variables?

Hello!

I am developing a small web-based application (customer-frontend).

It used to be quite small so that I keeped everything in one file (index.pl). In the head I defined all the variables etc. and that was it.

But now the application is getting a bit more complex with some scripts being only run from the command line and having nothing to do with the web-interface yet still sharing some common library.

So I decided to put some stuff into modules.

The problem that I now come up with is:
Where do I put the variables?

Before I just declared them as:
my $mysql_host = 'localhost';
[...]

Now I have several packages and they in turn use these variables as well.
I now use a self-written script which reads the variables from a textfile. And I put all this into a Module called Settings.pm.
So my call to a setting would be:
$Settings::value{'key'}
e.g.
$Settings::value{'mysql_host'}

But I am not too sure if this is the right way.

Do you have any hints to to deal with these settings properly?

Thanks in advance!
.