Configurable plugins
What problem are you trying to solve?
I tried using the postgres plugin, but I was unable to start the postgres server as I was already running another postgres server on the machine, and so there was a port conflict. On a devbox I don't need the server to listen on a port, the postgres plugin is already configured to connect on a unix socket, so the doesn't need to open a network port.
What solution would you like?
It would be nice if the plugin could be passed a configuration that would either allow it to disable network connectivity entirely or to configure the server to listen on a different port.
Alternatives you've considered
There is the option to put a configuration in devbox.d - I'm not sure how a solution using that would work though.
There kind is a way, but the plugin code needs to be modified. You can use an initialization script to check the value of an environment variable like PG_PORT which could hold the value "none" in your case to not bind to the port. Then you set the value of that variable in devbox.json.
It's a bit confusing at first, but the execution order of env/plugin init allow for that. Check the plugin lifecycle