my $tt = Template->new(
        {
            INCLUDE_PATH => $BASE_DIR . '/root/src/',
            INTERPOLATE  => 1,
        }
    ) || die "$Template::ERROR\n";
    $tt->process( $email_args{text_template},    

##</code><code>##

package Sam::Constants;
use Template;

our $tt = Template->new(                              # export me
        {
            INCLUDE_PATH => $BASE_DIR . '/root/src/',
            INTERPOLATE  => 1,
            CONSTANTS => { ... },
            VARIABLES => { ... },
        }
    ) || die "$Template::ERROR\n";

##</code><code>##

package Sam::Constants;
my @defaults_all = (... );
sub foo { return Template->new( @_ , @defaults_all, DEFAULTS_foo ) };
sub bar { return Template->new( @_ , @defaults_all, DEFAULTS_bar ) };

... # other file
use Sam::Constants qw/foo/;
my $tt = foo(LOCAL_CFG);
$tt->process();