Add ability to list current listening TCP ports

[mattrpav]

For remote management operations, it is helpful to be able to specify a management-only port so that the "application" port can be shutdown during long running database management operations such as an upgrade or restore.

1. Support the ability to have multiple TCP or SSL port listeners
2. Add the ability to start and stop TCP or SSL port listeners remotely

[katzyn]

Support the ability to have multiple TCP or SSL port listeners

You can start as many listeners as you need.

import org.h2.tools.Server;
// .....
Server s1 = Server.createTcpServer("-tcpPort", "5001", "-tcpPassword", "password1");
Server s2 = Server.createTcpServer("-tcpPort", "5002", "-tcpPassword", "password2");
s1.start();
s2.start();
// .....
s1.stop();
// .....
s1.start();

Add the ability to start and stop TCP or SSL port listeners remotely

You can stop a TCP server remotely with

Server.shutdownTcpServer("tcp://localhost:5002", "password2", true, false);

but unfortunately you can't start it in this way, but you can create a special database and create a user-defined function in it that will launch Server.createTcpServer(…).start() as a workaround.

[mattrpav]

@katzyn this is very helpful, thank you! I'll close this ticket after testing it out.

[mattrpav]

@katzyn I'm able to start and stop TcpServer instances using functions, thank you!

Follow-up question-- is it possible to get a list of TcpServer instances/listeners? I'm not finding not see anything in INFORMATION_SCHEMA, or a way to get a handle to the data within the TcpServer.SERVERS map.

If not, would you be open to accepting a patch for this functionality?

Thanks

[katzyn]

No, it isn't currently possible.

Personally I don't think that this information should be available for everyone who has any access to any database via INFORMATION_SCHEMA.

Perhaps we need a better infrastructure for such tasks.

[mattrpav]

@katzyn How about a static listPorts() method on TcpServer that listed the port numbers? It wouldn't be readily available in INFORMATION_SCHEMA, and users would have to define the custom function to access remotely. The security would effectively mirror what's there to write functions to start and stop listeners.

[mattrpav]

@katzyn I created a simple PR (#1989) to add a method to list the ports

[katzyn]

Unfortunately, your PR looks more like a hack and not like a proper implementation that we want to maintain. TcpServer is not a part of H2's API, it may be modified in any version without a warning.

I think we need to design a new secure management infrastructure that will be able to replace the management_db and cover all databases and all components of the server.

[mattrpav]

What would make this change less "like a hack"?