wrapper script to run remote command over ssh

ssh-exec

#!/usr/bin/env bash
# -----------------------------------------------------------------------------
# @author  Sreekanth S
# -----------------------------------------------------------------------------
#

function binary_exists() {
    which ${1} &> /dev/null
}

function log_error() {
    tput bold
    tput setaf 1
    printf "===> "
    tput setaf 7
    printf "Error: ${1}\n"
    tput sgr0
}

function log_info() {
    tput bold
    tput setaf 2
    printf "===> "
    tput setaf 7
    printf "$1\n"
    tput sgr0
}

function generate_and_copy_keys() {
    # check for dir exists. If not, then create it.
    if [ ! -d "${my_key_dir}" ]; then
        mkdir -p `dirname ${my_priv_key_file}`
    fi

    if [ ! -f "${my_priv_key_file}" -o ! -f "${my_pub_key_file}" ]; then
        log_info "Generating SSH keys.."
        # ssh-keygen -t rsa -N cgn -C "A comment.. usually an email is enough here..." -f ${my_priv_key_file}
        # echo -e 'y' | ssh-keygen -q -t rsa -N "" -f ${my_priv_key_file}
        ssh-keygen -q -t rsa -N "" -f ${my_priv_key_file}
        if [ $? -ne 0 ]; then
            log_error "Failed to generate keys. Exiting.."
            exit 2
        else
            log_info "Done.."
        fi
    fi

    log_info "Copying SSH public key to the remote machine.."
    if binary_exists ssh-copy-id ; then
        log_info "Using ssh-copy-id.."
        ssh-copy-id -i ${my_pub_key_file} -p ${port} ${user}@${remote_host}
    else
        cat ${my_pub_key_file} | ssh -p ${port} ${user}@${remote_host} "cat >> .ssh/authorized_keys"
    fi
    if [ $? -ne 0 ]; then
        log_error "Failed to copy public key to the target machine. Exiting.."
        exit 3
    else
        log_info "Done.."
    fi
}

function run_remote_command() {
    if [ "$#" -eq 0 ]; then
        log_info "Did you forget to provide the command ?"
        log_info "Let me leave you in remote's shell, take your time to enter the command."
        log_info "But, Don't forget to exit from remote shell.."
    fi
    ssh -tq -i ${my_priv_key_file} -o "PasswordAuthentication no" -p ${port} ${user}@${remote_host} $@
}

function show_help() {
    show_version
    echo -e "Usage:"
    echo -e "\t$(basename $0) [-v] [-p <port>] [<user>@]<hostname> [<command>]"
    echo -e "\t$(basename $0) -h"
    echo -e "\t$(basename $0) -V"
    echo -e "Options:"
    echo -e "\t-h           show this usage info"
    echo -e "\t-p <port>    specify SSH remote port [default: 22]"
    echo -e "\t-V           show version"
    echo -e "\t-v           verbose"
}

function show_version() {
    echo "$(basename $0) 1.0.0"
}

function parse_args() {
    while getopts "hp:Vv" opt; do
        case "$opt" in
            h) show_help; exit 0 ;;
            p) port=$OPTARG ;;
            V) show_version; exit 0 ;;
            v) verbose=1 ;;
            *) exit 129 ;;
        esac
    done

    shift $((OPTIND-1))
    [ "$1" = "--" ] && shift

    user=$(echo $1 | awk -F'@' '{print $1}')
    remote_host=$(echo $1 | awk -F'@' '{print $2}')

    if [ -z "${remote_host}" ]; then
        remote_host=${user}
        user=$USER
    fi

    shift

    if [ -z "${remote_host}" ]; then
        log_error "Remote hostname or ip address not provided"
        exit 1
    fi

    cmd=$@
}

######## Main ########

OPTIND=1
verbose=0
remote_host=""
user=""
port=22
cmd=""

parse_args $@

my_key_dir=${HOME}/.ssh/keys/${remote_host}
my_priv_key_file=${my_key_dir}/id_rsa_${user}
my_pub_key_file=${my_priv_key_file}.pub

run_remote_command "echo $HOSTNAME" > /dev/null
if [ $? -ne 0 ]; then
    generate_and_copy_keys
fi

run_remote_command ${cmd}