Put it in your derived class instead (and turn it into a class method.)

package MyConf;

...

BEGIN { 
    __PACKAGE__->_load_config;
}
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That will call _load_config (as a method) in your parent class, which will call config_file_path in your child class.

i see. in that case, i could just have the following line in my subclass:

BEGIN { __PACKAGE__->load_config('path/to/my.conf') }
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i prefer to not knowing that kind of detail in the parent class. another way that may look cleaner is

package BaseConf;

sub config_file_path { croak "must implemeted in subclass" }

sub load_config {
    my $self = shift;
    my $conf_file = $self->config_file_path;
    croak "unable to find $conf_file" unless -e $conf_file and -r $con
+f_file;

    my $cfg = Config::Tiny->read( $conf_file );
    croak "read config file '$conf_file' failed: $Config::Tiny::errstr
+" unless $cfg;
    return $cfg;
}

ub get {
    my $self = shift;
    my $cfg  = $self->load_config;
    croak "invalid method called $_[0]" if not exists $cfg->{_}->{ $_[
+0] };
    return $cfg->{_}->{ $_[0] };
}
sub import { ... } 
sub AUTOLOAD { .. } 

package MyConf;
use base 'BaseConf';

sub config_file_path { return "path/to/my.conf" }
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in plain CGI, Config::Tiny object is created for every config directive in sub import {}. maybe bad for performance. i am not sure if the same C::T object gets shared under mod_perl env.