SSH + Sudo + Expect in Bash script: Run command with sudo in remote machine

Question

I am trying to automate the deploy of some .deb packages with an script. I want to execute sudo dpkg -i $myDeb.deb in a list of remote machines I can access with ssh.

I've tried to automate the command with 'expect' inside a bash script, but I am obviously doing something wrong because I get a number of different errors (depending on where I put the quotation marks, basically)

This is the function I have (will be called with something like: _remoteInstallation "myPackage115.deb" "192.168.1.55". I know that in the remote machine, the .deb is going to be located in $HOME/Documents/:

function _remoteInstallation(){
    local retval=1
    local debToInstall=$(basename "$1")
    local remoteMachine="$2"
    spawned=$(expect -d -c "
          set timeout 1800
          spawn "/usr/bin/ssh -t borrajax@$remoteMachine /usr/bin/sudo /usr/bin/dpkg -i /home/borrajax/Documents/$debToInstall"'
          expect {
                \"Are you sure you want to continue connecting\" { send \"yes\r\"; exp_continue }
                \"password\" { send \"myPassword\r\";  exp_continue }
                \"[sudo] password\" { send \"myPassword\r\";  exp_continue }
                default { exit 1 }
          }
    " )
    retval=$?
    return $retval
}

With the quotes in the spawned area like that, I get

expect: invalid option -- 't'

If I change it to:

 spawn /usr/bin/ssh -t borrajax@$remoteMachine '/usr/bin/sudo /usr/bin/dpkg -i /home/borrajax/Documents/$debToInstall'

It looks like is trying to run the sudo dpkg command locally (first ssh(s) to '$remoteMachine' and then runs sudo dpkg locally, like two separate commands)

With this:

spawn '/usr/bin/ssh -t borrajax@$remoteMachine \'/usr/bin/sudo /usr/bin/dpkg -i /home/borrajax/Documents/$debToInstall\''

I get that couldn't execute "'/usr/bin/ssh": no such file or directory (which is not true)

... and at this point, I ran out of ideas... :-)

Any hint will be appreciated. Thank you.

Answer 1

What I use for a similar issue is putting all the remote-script into a file, say /usr/local/bin/debinstall.sh. My suggestion for that in your case would be: Have a special directory where you drop the packages into -- let's call it /tmp/remoteinstall to have an example. Additionally, put the user you connect to into the /etc/suduers file, and permit it to execute sudo dpkg -i * without being prompted for a password. debinstall.sh then would look like this:

#!/bin/bash
cd /tmp/remoteinstall
sudo dpkg -i *.deb && rm -f *

Make this script owned by and chmod 744 /usr/local/bin/debinstall.sh.

Locally, your job would simply be to upload your .deb files and call the script:

cd /path/to/files
scp * user@remotemachine:/tmp/remoteinstall
ssh user@remotemachine /usr/local/bin/debinstall.sh

debinstall.sh would then install your packages, and afterwards empty the directory only when the install finished successfully.

In case something is missing in the $PATH, remember that neither .bashrc nor .profile are executet this way -- so you might want to either source them at the beginning of the remote script, or define the appropriate PATH there.