Spring Security ApacheDSContainer should allow a zero port

ApacheDS's TcpTransport allows for a zero port, selecting any available port at startup. It does not correctly propagate that port up through the object graph, though.

For example, giving a TcpTransport a port of zero:

server = new LdapServer();
TcpTransport transport = new TcpTransport(port);
server.setTransports(transport);
server.start();

will result in a server that is listening on a random port, but server.getPort() still returns 0.

Because ApacheDS has not had a GA release in many years, it's unlikely that this enhancement will get applied to the ApacheDS project.

Still, it would be nice if ApacheDSContainer could accept 0 as a port value. One immediate benefit from this is reducing the likelihood of a port collision when multiple LDAP servers are started up simultaneously.

For this to happen, the following test would need to pass:

ApacheDSContainer container = new ApacheDSContainer("dc=springframework,dc=org",
        "classpath:test-server.ldif");
container.setPort(0);
container.afterPropertiesSet();
assertNotEquals(container.getPort(), 0);
assertNotEquals(container.server.getPort(), 0);
assertNotEquals(container.server.getPortSSL(), 0);

It may be possible to post-process the server instance in ApacheDSContainer#afterPropertiesSet into a state where the selected port is correctly returned.

Note that UnboundIdContainerTests has a test that would likely be good to port over into ApacheDSContainerTests for testing this feature.

Comment From: rwinch

Perhaps we can add another accessor on 'ApacheDsContsiner' that would be be used for getting the local port vs configured port?

Comment From: jzheaux

That could be nice, yes. I think it should be getConfiguredPort so that the same pattern can be applied to UnboundIdContainer which already supports a zero port.