ssh_tunnel gives "Waiting for connection on port ... " message about ssh HOT 6 CLOSED

R is single threaded so indeed you cannot run a tunnel and a client in the same R. But you can use something like the processx or callr to start a background R process for the tunnel:

proc <- callr::r_bg(function(){
  session <- ssh::ssh_connect('your.server.org')
  ssh::ssh_tunnel(session)
})

Or you can try the same thing with the sys package which prints progress to the parent R session:

str <- "session <- ssh::ssh_connect('dev.opencpu.org');ssh::ssh_tunnel(session)"
R <- R.home('bin/R')
pid <- sys::exec_background(R, c("-e", str))

from ssh.

Hi all, thanks for this useful discussion. I'm trying to connect to a postgres db using the code below.

cmd <- 'session <- ssh::ssh_connect("user@host");ssh::ssh_tunnel(session, port = 5555, target = "127.0.0.1:5432")'
pid <- sys::r_background(args = c("-e", cmd))

con <- DBI::dbConnect(
  RPostgres::Postgres(),
  dbname = "dbname",
  host = "127.0.0.1",
  port = 5555,
  user = "user",
  password = "pwd"
)

The tunnel sets up fine but when I run dbConnect I get the following message in the console:

client connected!
\ Tunneled 145 bytes...tunnel closed!
> 
> 
Error: could not connect to server: Connection reset by peer
	Is the server running on host "127.0.0.1" and accepting
	TCP/IP connections on port 5555?
Warning message:
Disconnecting from unused ssh session. Please use ssh_disconnect()

It seems that the tunnel is disconnecting before the connection code has a chance to run inside it? It's strange because if I open the same tunnel in the terminal and then run the connection code in R it works.

Is there any way to prevent the tunnel closing? Thanks!

from ssh.

I'm having same issue, getting around by opening a different R session and connecting there. But would be great to not have to use that workaround.

from ssh.

@jeroen Do you have any suggestion on how to make the background process prompt for the password of an ssh key?

In my setup I'd like to use

ssh_connect('[email protected]', keyfile = '~/.ssh/id_rsa')

However, using your solution with callr or sys does not work, as the background process cannot raise the password prompt that unlocks the ssh key.

from ssh.

Did you try setting your passphrase in the password argument in ssh_connect ()? If you are on linux or macos the best solution is it load your key in ssh-agent.

ssh_agent_add("~/.ssh/id_rsa")

Once the key is loaded in the agent, the you should be able to connect to your servers without passing a keyfile or passphrase.

from ssh.

@jeroen Awesome, ssh_agent_add works perfect. Thank you!!

A minor thing is that establishing the ssh tunnel takes a bit of time, but more than it takes for R to proceed. Do you have any idea how I could make sure R waits for the tunnel to be established before proceeding? At the moment I'm using Sys.sleep(1), but this doesn't seem quite right.

ssh::ssh_agent_add()
proc <- callr::r_bg(function(){
  session <- ssh::ssh_connect('[email protected]')
  ssh::ssh_tunnel(session, port = 5555, target = paste0('localhost:', 3306))
})
Sys.sleep(1)
con <- DBI::dbConnect(RMySQL::MySQL(),
                      username = 'user',
                      host = '127.0.0.1',
                      port = 5555,
                      password = rstudioapi::askForPassword('Database password'),
                      dbname = 'dbname')

from ssh.