002_provision_pi

#!/usr/bin/env bash

set -euo pipefail -o errtrace

SSH_KEY_TO_AUTHORIZE="$HOME/.ssh/id_ed25519.pub"
SSH_KEY_TO_ADD="$HOME/standard_raspberry_pi_key/id_ed25519.pub"
OLD_HOSTNAME="raspberrypi"
NEW_HOSTNAME="$OLD_HOSTNAME"

USER_NAME=""
PASSWORD=""
GIT_USER_EMAIL=''
GIT_USER_NAME=''
ENABLE_SPI=false
PRIV_SSH_KEY_FILE=''

# Make things require as little user input as possible.
# dont warn about hostkey not existing, don't add host key to known_hosts file since this may be a short lived
# "raspberrypi.local" host if we are changing the hostname anyway. Else subsequent hosts with the same name
# will have SSH errors if another machine's host key is already present under the "rapberrypi.local" hostname.
SSH_OPTS="-o StrictHostKeyChecking=no -o 'UserKnownHostsFile /dev/null'"

usage(){
    echo "Usage: $(basename "${0}") -u <USER_NAME> -p <PASSWORD> [-i <SSH_KEY_TO_AUTHORIZE>] [-j <SSH_KEY_TO_ADD>] [-h <NEW_HOSTNAME>] [-g <OLD_HOSTNAME>] [-e <GIT_USER_EMAIL>] [-f <GIT_USER_NAME>] [-s]"
    echo "Run this from laptop."
    echo "  -u USER_NAME            : User name for the raspberry pi's user account."
    echo "  -p PASSWORD             : Password for the raspberry pi's user account."
    echo "  -i SSH_KEY_TO_AUTHORIZE : path to ssh key to add to authorized_keys for passwordless login on raspberry pi"
    echo "                            Defaults to: $SSH_KEY_TO_AUTHORIZE"
    echo "  -j SSH_KEY_TO_ADD       : path to ssh key to copy to ~/.ssh on the raspberry pi. If you specify the public"
    echo "                            key path, the corresponding private key will also be copied and vice versa."
    echo "                            Defaults to: $SSH_KEY_TO_ADD"
    echo "  -h NEW_HOSTNAME         : Change the raspberry pi's hostname. Defaults to $OLD_HOSTNAME."
    echo "  -g OLD_HOSTNAME         : Defaults to $OLD_HOSTNAME"
    echo "  -e GIT_USER_EMAIL       : email address for git"
    echo "  -f GIT_USER_NAME        : user name for git"
    echo "  -s                      : Enable SPI"

    exit 1
}

main(){
    trap 'fail $? $LINENO' ERR

    parseOpts "$@"

    setupSsh
    provisionPi

    info "\\nDone provisioning raspberry pi!"
}

parseOpts(){
    while getopts ":u:p:i:j:h:g:e:f:s" opt; do
        case ${opt} in
            u) USER_NAME=${OPTARG} ;;
            p) PASSWORD=${OPTARG} ;;
            i) SSH_KEY_TO_AUTHORIZE=${OPTARG} ;;
            j) SSH_KEY_TO_ADD=${OPTARG} ;;
            h)
                if [[ "$OPTARG" =~ ^[a-z]([a-z0-9-]*[a-z0-9])?$ ]]; then
                    NEW_HOSTNAME=${OPTARG}
                else
                    warn "Invalid hostname."
                    usage
                fi
                ;;
            g) OLD_HOSTNAME=${OPTARG} ;;
            e) GIT_USER_EMAIL=${OPTARG} ;;
            f) GIT_USER_NAME=${OPTARG} ;;
            s) ENABLE_SPI=true ;;
            \?)
                warn "Invalid option: -$OPTARG"
                usage
                ;;
            :)
                warn "Option -$OPTARG requires an argument."
                usage
                ;;
            *) usage ;;
          esac
    done

    # Validation
    local has_usage_errors
    has_usage_errors=false
    if [ -z "$USER_NAME" ]; then
        has_usage_errors=true
        warn "Please supply a user name for the raspberry pi's user account with the flag: -u"
    fi
    if [ -z "$PASSWORD" ]; then
        has_usage_errors=true
        warn "Please supply a password for the raspberry pi's user account with the flag: -p"
    fi
    if [[ $has_usage_errors == "true" ]]; then
        usage
    fi
}

setupSsh(){
    info "\\nAuthorizing passwordless ssh with $SSH_KEY_TO_AUTHORIZE..."
    info "When asked for a password, please enter the raspberry pi's password: $PASSWORD\\n"

    local hostname_for_ssh
    hostname_for_ssh=$(getHostnameForSsh "$OLD_HOSTNAME")
    eval "ssh-copy-id $SSH_OPTS -i $SSH_KEY_TO_AUTHORIZE $USER_NAME@$hostname_for_ssh"

    if [[ ${SSH_KEY_TO_ADD} == *.pub ]]; then
        PUB_SSH_KEY_TO_ADD="$SSH_KEY_TO_ADD"
        PRIV_SSH_KEY_TO_ADD="${PUB_SSH_KEY_TO_ADD%.pub}"
    else
        PRIV_SSH_KEY_TO_ADD="$SSH_KEY_TO_ADD"
        PUB_SSH_KEY_TO_ADD="$PRIV_SSH_KEY_TO_ADD".pub
    fi
    PRIV_SSH_KEY_FILE=$(basename "$PRIV_SSH_KEY_TO_ADD")

    destination="$USER_NAME@$hostname_for_ssh:~/.ssh"
    info "\\nCopying $PUB_SSH_KEY_TO_ADD and $PRIV_SSH_KEY_TO_ADD to $destination..."
    eval "scp $SSH_OPTS $PUB_SSH_KEY_TO_ADD $PRIV_SSH_KEY_TO_ADD $destination"
}

provisionPi(){
    info "\\nProvisioning raspberry pi..."

    local hostname_for_ssh
    hostname_for_ssh=$(getHostnameForSsh "$OLD_HOSTNAME")
    provision_cmd="ssh $SSH_OPTS $USER_NAME@$hostname_for_ssh -- "
    provision_cmd+="'curl https://raw.githubusercontent.com/dasl-/pitools/main/provision_pi > provision_pi && "
    provision_cmd+="chmod a+x provision_pi && "
    provision_cmd+="./provision_pi -p $PASSWORD -h $NEW_HOSTNAME -i ~/.ssh/$PRIV_SSH_KEY_FILE -e $GIT_USER_EMAIL -f $GIT_USER_NAME -r "
    if [[ ${ENABLE_SPI} == "true" ]]; then
        provision_cmd+="-s "
    fi
    provision_cmd+="'"
    info "Running: $provision_cmd"
    eval "$provision_cmd"
}

getHostnameForSsh(){
    local hostname_for_ssh;
    hostname_for_ssh=$1

    # If it matches the hostname regex, assume its a hostname that we're supposed to append '.local' to.
    if [[ "$hostname_for_ssh" =~ ^[a-z]([a-z0-9-]*[a-z0-9])?$ ]]; then
        hostname_for_ssh="$hostname_for_ssh.local"
    fi

    # Otherwise, assume it's an IP address that we don't append '.local' to.
    echo "$hostname_for_ssh"
}

fail(){
    local exit_code=$1
    local line_no=$2
    local script_name
    script_name=$(basename "${BASH_SOURCE[0]}")
    die "Error in $script_name at line number: $line_no with exit code: $exit_code"
}

info(){
    echo -e "\x1b[32m$*\x1b[0m" # green stdout
}

warn(){
    echo -e "\x1b[33m$*\x1b[0m" # yellow stdout
}

die(){
    echo
    echo -e "\x1b[31m$*\x1b[0m" >&2 # red stderr
    exit 1
}

main "$@"