Modifying ssh connection command when running code --remote

[kamurani]

I am working on a tool that programmatically calls an instance of code to open a new window, and logs into a remote server over SSH.

The command looks something like this:

code --remote ssh-remote+mainserver-t5 "/path/to/remote/dir"

Dissecting that a bit, ssh-remote+mainserver-t5 is parsed and mainserver-t5 is treated as the HostName. However, I need to use an SSH jump host in order to get to the target node. So, I am using ProxyJump and using a login node (called mainserver) in order to reach the target node, t5.

As there are many target nodes that I could be assigned (t0 .. t99) and I don't wish to add a separate ProxyJump entry in my ~/.ssh/config file; I have generalised all of these with a single wildcard match.

~/.ssh/config looks like:

### My login node 
Host mainserver
  HostName my.server.example.com
  User user1 

### A specific target node 
Host t1
  HostName t1
  ProxyJump mainserver

### Placeholder for *any* arbitrary target node with wildcard matching... 
# Uses `-` character as delim 
# e.g. `ssh mainserver-t2` 
Host *-* 
  ProxyCommand ssh $(echo %h | cut -d- -f1) nc $(echo %h | cut -d- -f2) %p

Therefore, when VScode runs the SSH connection, it treats mainserver-t5 as any old hostname; but under the hood, SSH parses out mainserver and t5 (as per the wildcard-matching entry in the config file) and provides the connection via a ProxyJump.

I would prefer users of my program to not need to add this placeholder to their ~/.ssh/config, and therefore I'm looking for a way to directly modify the ssh command that is used under the hood by VScode.

Upon viewing some verbose debug output, I can see the actual command that is run after doing code --remote:

[09:26:12.233] Spawned 63186
[09:26:12.234] Using connect timeout of 62 seconds
[09:26:12.343] > local-server-1> Running ssh connection command: ssh -v -T -D 56023 -o ConnectTimeout=60 mainserver-t5
[09:26:12.345] > local-server-1> Spawned ssh, pid=63206
[09:26:12.364] stderr> OpenSSH_9.8p1, LibreSSL 3.3.6

Is there an easy way to directly modify this command? In which case, I could simply append the -J option and provide the two hostnames as required; rather than relying on this argument being given by the ProxyJump entry in the config file.

Thanks in advance!