nginx sharding

gistfile1.txt

server {
  listen  80;
  listen  443 ssl;
  server_name     api.domain.com;
  keepalive_timeout       5;
  root /home/rails/api.domain.com/current;

  ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
  ssl_certificate         /etc/nginx/ssl/domain.com.chained.crt;
  ssl_certificate_key     /etc/nginx/ssl/domain.key;

  access_log /var/log/nginx/api.domain.com-access.log;
  error_log /var/log/nginx/api.domain.com-error.log warn;
  error_page   500 502 503 504  /500.html;

  location ~ ^/(assets|images|javascripts|stylesheets|system|favicon\.ico|robots\.txt)/  {
    return 444;
  }

  location / {
    try_files $uri @app;
    add_header      Access-Control-Allow-Credentials        true;
    add_header      Access-Control-Allow-Origin $http_origin;
  }

  location @app {

    perl '
      sub {
        my $r = shift;
        my $request_shop_id = "";
        if ($r->request_method eq "GET") {
          if($r->args =~ /shop_id=([a-z0-9A-Z]+)/ ) {
            my $shop_id = "$1";
            my $shard_id = find_shard($shop_id);
            if($shard_id ne "") {
              $r->internal_redirect("/shard" . $shard_id . $r->uri . "?" .  $r->args);
              return;
            }
          }
          $r->internal_redirect("/shard_not_found");
        } else {
          $r->has_request_body(\&post);
        }
      };

      sub post {
        my $r = shift;
        if( $r->request_body ne "" && $r->request_body =~ /shop_id=([a-z0-9A-Z]+)/ ) {
          my $shop_id = "$1";
          my $shard_id = find_shard($shop_id);
          if($shard_id ne "") {
            $r->internal_redirect("/shard" . $shard_id . $r->uri . "?" .  $r->args);
            return;
          }
        }
        $r->internal_redirect("/shard_not_found");
      };

      sub find_shard {
        my $shop_id = shift;
        open(my $fh, "<", "/home/rails/nginx_shop_mapping.conf") or die("cant open filename");
        while(my $row = <$fh>) {
          chomp $row;
          if($row ne "") {
            @parts = split / /, $row;
            if(@parts[0] eq $shop_id) {
              close $fh;
              return $parts[1];
            }
          }
        }
        close $fh;
        return "";
      }
    ';
  }


  location /shard0 {
    rewrite    /shard0(.*) $1 break;
    proxy_pass              http://api-0;
    proxy_redirect  off;
    include /etc/nginx/api_proxy_params.conf;
  }

  location /shard1 {
    rewrite    /shard1(.*) $1 break;
    proxy_pass              http://api-1;
    proxy_redirect  off;
    include /etc/nginx/api_proxy_params.conf;
  }

  location /shard_not_found {
    return 403;
  }

}