Command line arguments to repl/rebel-remote don't work

[toburger]

The same command line args as applied to repl/remote do not work with repl/rebel-remote.
--host and --port do not have any effect.

[practicalli-johnny]

Maybe I am missing something but I havent been able to replicate the issue you have been experiencing

Are the more details you can supply, e.g. the command used, any network infrastructure being navigated or a project that recreates the issue.

Thanks.

[toburger]

After investigating a bit more I think I've found the "real" cause of the problem:

The remote NREPL gets registered with the host localhost (see the printed out nrepl://localhost:44947):

When i execute a netcat command I can't reach the service:

So I think I have to startthe nrepl-Server with the actual host name. The repl/... commands do have a parameter to specify the host name?

[practicalli-johnny]

Ah yes, I remember the --bind is a server option is required to set the hostname that the nrepl server starts on. If --bind is not set, the default locahost IP address is used

❯ clojure -M:repl/rebel --bind 192.168.0.212 --port 44445
WARNING: abs already refers to: #'clojure.core/abs in namespace: clojure.test.check.generators, being replaced by: #'clojure.test.check.generators/abs
nREPL server started on port 44445 on host 192.168.0.212 - nrepl://192.168.0.212:44445
[Rebel readline] Type :repl/help for online help info
user=> 

When connecting via the --connect option, the --host option is the client argument that specifies the address set by --bind on the server

Its quite easy to get --host and --bind confused.

The nrepl docs provide some other options, including defining a configuration file.

[toburger]

Ah, that's exactly what happened! I've tried it with --host and nothing happened so I thought there is no option for that! 😅 Thanks for the hint!

Now the repl/remote works like a charm. But the repl/rebel-remote doesn't seem to use the --host argument.

Sorry, I had to hide the host for security reasons but I can assure that the they go to the same host.

[practicalli-johnny]

Update: sorry, I forgot that --connect was already included in the alias... try using nrepl as a client alone, without rebel readline
https://nrepl.org/nrepl/usage/clients.html#using-the-built-in-client

I believe the --connect option is also required as well as the --host and --port options

clojure -M:repl/rebel-remote --connect --host hostname --port 8083

I dont have a remote setup at the moment to test.

If the above doesnt work, then try using nrepl directly as a remote REPL client
https://nrepl.org/nrepl/usage/clients.html#using-the-built-in-client

[practicalli-johnny]

I have only managed to get a remote connection by first establishing an SSH forwarding connection. This only seems to work with nrepl connect command locally, using the :repl/rebel-remote rebel readline alias does not seem to know about the remote repl state :(

The Cider docs recommend using a TLS approach

Remote server

Start the REPL process on the remote machine, specifying the port

clojure -M:repl/basic --port 1234

SSH tunnel

Create an ssh local forward tunnel to the remote machine

ssh -L :1234:192.168.0.212:1234 practicalli@192.168.0.238 -N -v

This will prompt for the user password, e.g. practicalli is the name of the user account on the remote machine.

192.168.0.212 is the IP address of the local machine and 192.168.0.238 is the IP address of the remote machine (replace with your own IP addresses)

Local connection

On the local machine (in a separate terminal prompt), connect to the local port and and nrepl commands will be sent via SSH to the REPL process running on the remote server.

clojure -M:repl/basic --connect --host localhost --port 1234

Testing

At the REPL prompt on the remote server, define a var, e.g.

(def remote-value 42)

At the REPL prompt on the local server, evaluate the var name

remote-value

This should display the value 42 in the local repl prompt.

The process is simpler if using Emacs cider-connect-clj to connect to the remote repl :)

[practicalli-johnny]

If using Emacs Cider as the local REPL connection, define a local SSH connection in the .ssh/config file.

Host gkar-repl
  HostName 192.168.0.238
  # IdentityFile /home/practicalli/.local/joint-clojure-machine.pem
  User practicalli
  PasswordAuthentication yes
  LocalForward 1234 localhost:1234
  Port 22

Uncomment the IdentityFile if there are pem certificates available. Otherwise Emacs Cider will prompt for the user account password on the remote machine.

In Emacs, run the cider-connect-clj command and select the Host definition from the list of connections, e.g. gkar-repl or enter the IP address of the remote server

Enter the port, e.g 1234

Emacs cider should connect to the remote repl state.

[toburger]

Thanks for the thorough testing!
I've managed to connect via SSH tunnel and Cider and it works!

But in summary we can definitely say that repl/rebel-remote ignores --host and --port parameters.

Which is fine for me if I know the limitations but on the other hand the command is misleading as it implies that it is possible to connect to a remote REPL.

[practicalli-johnny]

Marked the alias as DEPRECATED and will move to the deps-deprecated.edn file by the next release