my @dimensions = qw/ page_path /;
my @metrics = qw/ pageviews unique_pageviews avg_time_on_page entrances exits /;

.
.
.
 (get the data into $res, this works fine)

foreach my $r (@{ $res->rows }){
      my @line;
      foreach my $get ( @dimensions, @metrics ){
        my $get_method = "get_$get";
        push @line, $r->{$get_method}->(); # this is wrong
      }
      push @report, join( "\t", @line);
    }