* Let OS allocate port number
Port availability might be tricky if some port is already in use on the
'all' interface '0.0.0.0'.
The proposed solution is to let the OS allocate the port for us using 0
as port specifier :
- first create a server instance to allocate a port number
- save port number
- close the server
- return the port number to the caller
This should be safe granted the OS doesn't reuse the port numbers on
consecutive port allocations.
see :
- about Node.js Net module : https://nodejs.org/docs/latest-v12.x/api/net.html#net_server_listen_port_host_backlog_callback
- about safety around reusing port number : https://unix.stackexchange.com/a/132524
Signed-off-by: Alexis Deruelle <alexis.deruelle@gmail.com>
