Connection to the port is busy…

If your address is in use because you’re rapidly developing and not properly closing connections, you’re not alone.

My first post here inevitably supposed to be about the issue I encountered the most while “developing” this website. The process (as usual in such situations) consisted mainly of adding a feature and restarting everything. During this constant back-and-forth, I frequently encountered the following error:

Error: Address already in use - bind(2) for 127.0.0.1:4000

It happened so often that I decided to document the solution here, so I never forget it again.

You can resolve this issue by first finding the process ID (PID) that is occupying the port:

lsof -i :4000

It will give you output something like:

COMMAND   PID USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
ruby    58101  vdk    9u  IPv4 0x4032def487f7a1bf      0t0  TCP localhost:terabase (LISTEN)

After this you can get rid off the nasty process!

kill -9 58101

And continue to create new bugs.