login.sh

#!/bin/bash

set -e

readonly LASTPASS_KEY_LABEL='ssh_private_key'

function usage {
    echo 'Usage: '
    echo 'pivotal_login <lastpass username> [options...]'
    echo
    echo "Beginner's guide"
    echo 'Your first time, run:'
    echo 'pivotal_login donald.knuth@pivotal.io -t 8 --import-private-key /mnt/path/to/private_key --save-alias dk'
    echo 'The next times, run:'
    echo 'pivotal_login dk [-t <hours>]'
    echo
    echo 'List of options:'
    echo 'To specify a number of hours for which you want to stay logged in:'
    echo '--time-in-hours <hours> (-t for short)'
    echo "To not be prompted to login to lastpass if you're already logged in:"
    echo '-n'
    echo 'To import your private key and write it to lastpass, use the option:'
    echo '--import-private-key <path to private key> (-k for short)'
    echo 'To save your username and settings with a short alias, use:'
    echo '--save-alias <xx>'
    echo 'Then, you can run "pivotal_login <xx>"'
    echo
    echo 'To logout, just run '
    echo 'pivotal_login --logout (-o for short)'
}

POSITIONAL=("$@")
HOURS=1
IMPORT_KEY='false'
LOGIN_TO_LASTPASS='true'

USERNAME="$1"

if [[ -z "$USERNAME" ]]; then
    echo 'You need to specify your lastpass username or an alias as the first argument.'
    echo
    usage
    exit 2
fi

case $USERNAME in
    -h|--help)
        usage
        exit 0
        ;;
esac

shift # skip username

while [[ $# -gt 0 ]]
do
    key="$1"

    case $key in
	-t|--time-in-hours)
	    HOURS="$2"
	    shift # past argument
	    shift # past value
	    ;;
	-k|--import-private-key)
	    IMPORT_KEY='true'
	    KEY_FILE_PATH="$2"
	    shift # past argument
	    shift # past value
	    ;;
        -n)
            LOGIN_TO_LASTPASS='false'
            shift
            ;;
        --save-alias)
            SAVE_ALIAS="$2"
            shift
            shift
            ;;
	-h|--help)
	    usage
	    exit 0
	    ;;
	*)    # unknown option
	    echo "unrecognized option \"$1\""
	    exit 6
	    ;;
    esac
done
set -- "${POSITIONAL[@]}" # restore positional parameters

function fetch_private_key {
    set +x
    KEY=`lpass show "$LASTPASS_KEY_LABEL" --notes 2> /dev/null`
    return $?
}

function import_private_key {
    LPASS_USERNAME="$1"
    KEY_FILE_PATH="$2"

    if [[ ! -f "$KEY_FILE_PATH" ]]; then
        echo "The file \"$KEY_FILE_PATH\" doesn't exist."
	exit 3
    fi

    if fetch_private_key ; then
	echo "There already is a note called \"$LASTPASS_KEY_LABEL\" in your lastpass vault."
	echo 'Aborting'
	exit 4
    fi

    cat "$KEY_FILE_PATH" | lpass add --non-interactive --notes "$LASTPASS_KEY_LABEL"
    if [[ $? ]]; then
	echo 'Your private key was successfully saved in your lastpass vault!'
    else
	echo "Your private key couldn't be saved to lastpass. Aborting."
	exit 5
    fi
}

readonly STORE="${HOME}/.pivotal_login"

function save_alias {
    ALIAS=$1
    LP_USER=$2
    if [[ ! -f "$STORE" ]]; then
        touch $STORE
    fi
    if grep "^${ALIAS}#" "$STORE"; then
        echo "The alias ${ALIAS} is already taken. Pick another one or delete it from ${STORE}"
        exit 7
    fi
    if echo "$ALIAS" | grep -e '#' -e '@'; then
        echo 'The alias cannot contain the characters # or @.'
        exit 8
    fi
    echo "${ALIAS}#${LP_USER} -t ${HOURS}" >> "${STORE}"
}

function find_alias {
    ALIAS=$1

    STORE_LINE=$(grep "^${ALIAS}#" "${STORE}")
    if [[ "$?" = 0 ]]; then
        ALIAS_OPTIONS=$(echo "$STORE_LINE" | cut -d# -f2)
    else
        echo "The alias \"$ALIAS\" cannot be found."
        exit 9
    fi
}

function options_from_username {
    USERNAME=$1

    if echo "$USERNAME" | grep '@' > /dev/null; then
        LPASS_USERNAME=$1
    else
        find_alias $USERNAME
        OPTIONS="$ALIAS_OPTIONS"
    fi
}

function logout {
    set -e
    /usr/bin/ssh-add -D
    lpass logout -f
    echo 'You sucessfully logged out!'
    exit 0
}

if [[ "$USERNAME" = '-o' || "$USERNAME" = "--logout" ]]; then
    logout
fi

options_from_username "$USERNAME"

if [[ -n "$OPTIONS" ]]; then
    shift # get rid of alias
    options=($OPTIONS $@)
    $0 ${options[@]}
    exit $?
fi

if [[ ${LOGIN_TO_LASTPASS} = 'true' ]]; then
    export LPASS_AGENT_TIMEOUT=$((HOURS * 60 * 60))
    lpass login "${LPASS_USERNAME}"
    unset LPASS_AGENT_TIMEOUT
fi

if [[ "$IMPORT_KEY" = 'true' ]]; then
    import_private_key "$LPASS_USERNAME" "$KEY_FILE_PATH"
fi

if ! fetch_private_key ; then
    echo "Your private key couldn't be found in lastpass."
    echo "Set it to be able to login."
    exit 1
fi

if [[ -n ${SAVE_ALIAS} ]]; then
    save_alias "$SAVE_ALIAS" "$LPASS_USERNAME"
fi

ps -p $SSH_AGENT_PID > /dev/null || eval "$(ssh-agent)"

/usr/bin/ssh-add -D
/usr/bin/ssh-add -t "${HOURS}H" - <<< "${KEY}"
echo "Identity added for ${HOURS} hours"

unset KEY