function apt_install { # Report any packages already installed. PACKAGES=$@ TO_INSTALL="" for pkg in $PACKAGES; do if dpkg -s $pkg 2>/dev/null | grep "^Status: install ok installed" > /dev/null; then echo $pkg is already installed \(`dpkg -s $pkg | grep ^Version: | sed -e "s/.*: //"`\) else TO_INSTALL="$TO_INSTALL""$pkg " fi done # List the packages about to be installed. if [[ ! -z "$TO_INSTALL" ]]; then echo installing $TO_INSTALL... fi # 'DEBIAN_FRONTEND=noninteractive' is to prevent dbconfig-common from asking you questions. DEBIAN_FRONTEND=noninteractive apt-get -qq -y install $PACKAGES > /dev/null; } function get_default_hostname { # Guess the machine's hostname. It should be a fully qualified # domain name suitable for DNS. None of these calls may provide # the right value, but it's the best guess we can make. set -- $(hostname --fqdn 2>/dev/null || hostname --all-fqdns 2>/dev/null || hostname 2>/dev/null) printf '%s\n' "$1" # return this value } function get_default_publicip { # Get the machine's public IP address. The machine might have # an IP on a private network, but the IP address that we put # into DNS must be one on the public Internet. Try a public # API, but if that fails (maybe we don't have Internet access # right now) then use the IP address that this machine knows # itself as. get_publicip_from_web_service || get_publicip_fallback } function get_publicip_from_web_service { # This seems to be the most reliable way to determine the # machine's public IP address: asking a very nice web API # for how they see us. Thanks go out to icanhazip.com. curl --fail --silent icanhazip.com 2>/dev/null } function get_publicip_fallback { # Return the IP address that this machine knows itself as. # It certainly may not be the IP address that this machine # operates as on the public Internet. The machine might # have multiple addresses if it has multiple network adapters. set -- $(hostname --ip-address 2>/dev/null) \ $(hostname --all-ip-addresses 2>/dev/null) while (( $# )) && is_loopback_ip "$1"; do shift done printf '%s\n' "$1" # return this value } function is_loopback_ip { # helper for get_publicip_fallback [[ "$1" == 127.* ]] } function ufw_allow { if [ -z "$DISABLE_FIREWALL" ]; then # ufw has completely unhelpful output ufw allow $1 > /dev/null; fi }