Close an exiseting SSH tunnel before creating a new one with cider-connect

[JMacLulich]

I have had this problem for a long long time.

And with GPT-4 I finally got motivated enough to try and solve it.

My problem is when I cider-connect to a remote host via SSH it creates a tunnel -- that's fine.

Every subsequent connect to a different host uses the same tunnel which is tunneling to the first host.

It's so very annoying, I have to manually tear down the tunnel and re-establish it to connect to the right remote host.

I wanted a cider function that would look for existing SSH connections on the same port and tear them down so that a new one to the right remote host is established.

GPT-4 got me this far, but the var cider--connections is not defined (as is maybe others) and I don't know how ot proceed from here.

Any advice would be great (my emacs lisp is very basic, because I've actively tried to avoid it).

p.s. if possible I would love it to to host auto-completion the same way cider-connect already does, but cider-known-hosts seems to be nil.

(defun cider-connect-and-close-existing ()
  "Connect to a REPL, closing existing connections on the same port."
  (interactive)
  (if (boundp 'cider-known-hosts)
      (let ((hostname (completing-read "Host: " cider-known-hosts))
            (port (read-number "Port: " 7777))) ; Change the default port to 7777
        (let ((existing-connections (seq-filter
                                     (lambda (connection)
                                       (and (equal (cider--remote-host connection) hostname)
                                            (equal (cider--remote-port connection) port)))
                                     (cider--connections))))
          (dolist (conn existing-connections)
            (message "Closing existing connection to %s:%s" hostname port)
            (cider--close-connection conn)))
        (cider-connect-clj hostname port))
    (message "cider-known-hosts is not available, define your own list of known hosts.")))

(global-set-key (kbd "C-c C-o") 'cider-connect-and-close-existing)

[vemv]

Created #3537 - let's see what we can do about it!