anchor.diff:      # Generate a configuration file in /etc/containers for each
       # container so that container@.target can get the container
       # configuration.
  -    environment.etc = mapAttrs' (name: cfg: nameValuePair "containers/${name}.conf"
  +    environment.etc =
  +      let mkPortStr = p: p.protocol + ":" + (toString p.hostPort) + ":" + (if p.containerPort == null then toString p.hostPort else toString p.containerPort); 
  +      in mapAttrs' (name: cfg: nameValuePair "containers/${name}.conf"
         { text =
             ''
               SYSTEM_PATH=${cfg.path}
  
positive.code:           extraFlags+=" --network-bridge=$HOST_BRIDGE"
          fi
          if [ -n "$HOST_PORT" ]; then
  	  OIFS=$IFS
  	  IFS=","
            for i in $HOST_PORT
  	  do
                extraFlags+=" --port=$i"
  	  done
  	  IFS=$OIFS
          fi
        fi
  
  
negative.code:       '';
      };
  
      forwardPorts = mkOption {
        type = types.listOf (types.submodule {
          options = {
            protocol = mkOption {
              type = types.str;
              default = "tcp";
              description = "The protocol specifier for port forwarding between host and container";
            };
            hostPort = mkOption {
              type = types.int;
              description = "Source port of the external interface on host";
            };
            containerPort = mkOption {
              type = types.nullOr types.int;
              default = null;
              description = "Target port of container";
            };
          };
        });
        default = [];
        example = [ { protocol = "tcp"; hostPort = 8080; containerPort = 80; } ];
        description = ''
          List of forwarded ports from host to container. Each forwarded port is specified by protocol, hostPort and containerPort. By default, protocol is tcp and hostPort and containerPort are assumed to be the same if containerPort is not explicitly given. 
        '';
      };
  
  