Nginxでmrubyを使ってredirectする時にログが出ない問題

nginx.conf

    log_format redirect_local_ltsv 
        'domain:$host\t'
        'host:$http_x_forwarded_for\t'
        'time:$time_local\t'
        'etag:$http_etag\t'
        'etag?:$http_if_none_match\t'
        'msec:$msec\t'
    ;

    log_format redirect_absolute_ltsv 
        'domain:$host\t'
        'host:$http_x_forwarded_for\t'
        'time:$time_local\t'
        'etag:$http_etag\t'
        'etag?:$http_if_none_match\t'
        'msec:$msec\t'
    ;

    log_format redirect_google_ltsv 
        'domain:$host\t'
        'host:$http_x_forwarded_for\t'
        'time:$time_local\t'
        'etag:$http_etag\t'
        'etag?:$http_if_none_match\t'
        'msec:$msec\t'
    ;

    server {
        listen       80;

        location /index.html {
            root /Users/shinichiro/;
        }

        location ~ /redirect_local/ {
            access_log logs/redirect_local_ltsv.log redirect_local_ltsv;
            mruby_access_handler /Users/shinichiro/redirect_local.rb;
        }

        location ~ /redirect_absolute/ {
            access_log logs/redirect_absolute_ltsv.log redirect_absolute_ltsv;
            mruby_access_handler /Users/shinichiro/redirect_absolute.rb;
        }

        location ~ /redirect_google/ {
            access_log logs/redirect_google_ltsv.log redirect_google_ltsv;
            mruby_access_handler /Users/shinichiro/redirect_google.rb;
        }
    }

redirect_absolute.rb

Nginx.redirect "http://sample.com/index.html" , Nginx::HTTP_MOVED_TEMPORARILY

redirect_google.rb

Nginx.redirect "https://www.google.co.jp/?gws_rd=ssl" , Nginx::HTTP_MOVED_TEMPORARILY

redirect_local.rb

Nginx.redirect "/index.html" , Nginx::HTTP_MOVED_TEMPORARILY

問題

redirect_absolute.rbを経由して、ホストを指定せずにローカル内でリダイレクトした時にログが出力されない。
他の2パターンはログに出力される。
Nginx + mrubyのバグだろうか。

解決策

とりあえずやっつける。

redirect_local.rb

var        = Nginx::Var.new
req        = Nginx::Request.new
Nginx.redirect "http://" + var.host + "/index.html" , Nginx::HTTP_MOVED_TEMPORARILY