The startup line printed config.bind_addr, so BIND_ADDR=127.0.0.1:0 - ask the OS for whichever port is free - always logged ":0" instead of whatever port actually opened. Reads listener.local_addr() instead, the resolved address axum's Listener trait already has once the bind succeeds. Needed by the next commit's dev-instance.sh, which has no other way to discover the port it just asked the OS to pick. Change-Id: I9cc00f99059ba746b8293fd2814ae726a2c5d5be