Narrow the port range, assigned to monitors and/or clients

[gikari]

I'm trying to set up Docker environment with RoboCup server, clients and monitors. Monitor is a GUI app and therefore it cannot be easily run in docker. Because of that, I need to expose some ports of the server, so that is can connect from outside of Docker network.

Unfortunately after the connection to the default 6000 port, the server assigns a new port to the monitor, which is random in a possible range from 30000 to 60000 or may be even more. Because of that fact, I need to bind a lot of ports, when setting up a docker container. This is a very slow operation and because of that I cannot create a docker container in a reasonable time (See also).

To fix that issue, I propose to narrow the port range, which is assigned to the monitor and/or clients. For example a range with 100 ports would be sufficient. It is relatively fast, when running a docker container, to bind them, covers 22 players and additionally a lot of monitors.

If that range is too low for some reason, it would be nice at least make the range configurable.

[hidehisaakiyama]

As you mentioned, the monitor connection is one of the problems. I'm not so familiar with network programming, I'm not sure assigning the port range is a better solution or not. However, it would be nice we separate the monitor port from the player's one.

Another idea is a proxy client. Now, I'm planning to develop a simple proxy client that transfers the monitor message via TCP/IP.

[bandreghetti]

@gikari I don't know if you still need it but we have done something very similar in https://github.com/rcssggb/ggb-demo by exposing the X11 server to the container running rcssmonitor using the xhost utility. Feel free to reach out if you have any questions! I also believe an option to limit the port range would be a nice feature to make easier working with rcss in containers.