views:

156

answers:

3

I've been trying to write a small library using Thor to help assist me in quick creating new projects and sites. I wrote this small method:

def ssh(cmd)
  Net::SSH.start( server_ip, user, :port => port) do |session|
    session.exec cmd
  end
end

to just assist me in running quick commands on remote servers when needed.

The problem is when I need to run a command under sudo on the remote end, the script just seems to hang on me. For example when executing this...

ssh("sudo cp #{file_from_path} #{file_to_path}" )

The script will prompt me for a password

[sudo] password for user:

But then the whole thing hhangs after typing it in.

Would anyone happen to know why it hangs exactly, and what I can do to run sudo command on a remote server under Net::SSH (or some alternative)?

*note: Before suggested, I had originally started writing this library as a recipe under Capistrano, until I came upon Thor, and thought it would be a good chance to try it out. I'm not against having to switch the whole thing back to Capistrano if needed, but I'd just be really surprised if there isn't an easy way to run sudo commands on a remote server.

+1  A: 

The first thing you might want to try is using public keys instead of passwords to login. Then also try running the command from the interactive shell.

For example:

(This part really depends on the server/client software you have)

$ ssh-keygen
$ scp .ssh/id-dsa.pub server:
$ ssh server
server$ cat id-dsa.pub >> .ssh/authorizedkeys

$ scp -c "ls"

this should work without any prompts, if the key sharing was successful.

sukru
Actually I am using public keys. The password it's prompting for isn't the password for the ssh connection, but the password for sudo to run the command. So I at least know it connects, but it hangs after I fill in the sudo password.
japancheese
You might try setting sudo not to ask for a password for the specific user.
sukru
I had tried this in the sudoers file on the remote server by adding the follower lines at the end "user ALL=(ALL) ALL", but I'm still getting prompted. Am I doing this incorrectly?
japancheese
From the manual: "By default, sudo requires that a user authenticate him or herself before running a command. This behavior can be modified via the NOPASSWD tag."
sukru
Got it working with the NOPASSWD tag. The syntax is "user ALL=NOPASSWD: ALL" for anyone looking for the info. @sukru, assuming I am using keys to access from my personal computer though, are there any inherent security risks with this method that I should be concerned with?
japancheese
+1  A: 

It's possible to set it up with net/ssh, but it's really too much effort, just execute ssh command like this:

system("ssh", "-t", "#{user}@#{host}", "sudo cp #{file_from_path} #{file_to_path}")

This -t means to allocate a tty. Without it it will still work, but your password will be seen in clear.

(I assume you intend to type sudo password manually. If not, go the authorized keys way).

taw
A: 

hello jap ,have you solved this problem??

AMIT
first, the name you want is @japancheese, not "jap". second, this is not an answer, it would have been better as a comment to the question.
Zabba