143 lines
4.7 KiB
Bash
143 lines
4.7 KiB
Bash
function hide_output {
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# This function hides the output of a command unless the command fails
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# and returns a non-zero exit code.
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# Get a temporary file.
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OUTPUT=$(tempfile)
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# Execute command, redirecting stderr/stdout to the temporary file.
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$@ &> $OUTPUT
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# If the command failed, show the output that was captured in the temporary file.
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if [ $? != 0 ]; then
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# Something failed.
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echo
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echo FAILED: $@
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echo -----------------------------------------
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cat $OUTPUT
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echo -----------------------------------------
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fi
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# Remove temporary file.
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rm -f $OUTPUT
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}
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function apt_install {
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# Report any packages already installed.
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PACKAGES=$@
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TO_INSTALL=""
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ALREADY_INSTALLED=""
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for pkg in $PACKAGES; do
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if dpkg -s $pkg 2>/dev/null | grep "^Status: install ok installed" > /dev/null; then
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if [[ ! -z "$ALREADY_INSTALLED" ]]; then ALREADY_INSTALLED="$ALREADY_INSTALLED, "; fi
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ALREADY_INSTALLED="$ALREADY_INSTALLED$pkg (`dpkg -s $pkg | grep ^Version: | sed -e 's/.*: //'`)"
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else
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TO_INSTALL="$TO_INSTALL""$pkg "
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fi
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done
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# List the packages already installed.
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if [[ ! -z "$ALREADY_INSTALLED" ]]; then
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echo already installed: $ALREADY_INSTALLED
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fi
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# List the packages about to be installed.
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if [[ ! -z "$TO_INSTALL" ]]; then
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echo installing $TO_INSTALL...
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fi
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# 'DEBIAN_FRONTEND=noninteractive' is to prevent dbconfig-common from asking you questions.
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#
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# Although we could pass -qq to apt-get to make output quieter, many packages write to stdout
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# and stderr things that aren't really important. Use our hide_output function to capture
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# all of that and only show it if there is a problem (i.e. if apt_get returns a failure exit status).
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#
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# Also note that we still include the whole original package list in the apt-get command in
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# case it wants to upgrade anything, I guess? Maybe we can remove it. Doesn't normally make
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# a difference.
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DEBIAN_FRONTEND=noninteractive \
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hide_output \
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apt-get -y install $PACKAGES
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}
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function get_default_hostname {
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# Guess the machine's hostname. It should be a fully qualified
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# domain name suitable for DNS. None of these calls may provide
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# the right value, but it's the best guess we can make.
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set -- $(hostname --fqdn 2>/dev/null ||
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hostname --all-fqdns 2>/dev/null ||
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hostname 2>/dev/null)
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printf '%s\n' "$1" # return this value
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}
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function get_default_publicip {
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# Get the machine's public IP address. The machine might have
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# an IP on a private network, but the IP address that we put
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# into DNS must be one on the public Internet. Try a public
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# API, but if that fails (maybe we don't have Internet access
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# right now) then use the IP address that this machine knows
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# itself as.
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get_publicip_from_web_service 4 || get_default_privateip 4
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}
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function get_default_publicipv6 {
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get_publicip_from_web_service 6 || get_default_privateip 6
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}
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function get_publicip_from_web_service {
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# This seems to be the most reliable way to determine the
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# machine's public IP address: asking a very nice web API
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# for how they see us. Thanks go out to icanhazip.com.
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# See: https://major.io/icanhazip-com-faq/
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#
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# Pass '4' or '6' as an argument to this function to specify
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# what type of address to get (IPv4, IPv6).
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curl -$1 --fail --silent icanhazip.com 2>/dev/null
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}
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function get_default_privateip {
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# Return the IP address of the network interface connected
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# to the Internet.
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#
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# We used to use `hostname -I` and then filter for either
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# IPv4 or IPv6 addresses. However if there are multiple
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# network interfaces on the machine, not all may be for
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# reaching the Internet.
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#
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# Instead use `ip route get` which asks the kernel to use
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# the system's routes to select which interface would be
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# used to reach a public address. We'll use 8.8.8.8 as
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# the destination. It happens to be Google Public DNS, but
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# no connection is made. We're just seeing how the box
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# would connect to it. There many be multiple IP addresses
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# assigned to an interface. `ip route get` reports the
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# preferred. That's good enough for us. See issue #121.
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#
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# Also see ae67409603c49b7fa73c227449264ddd10aae6a9 and
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# issue #3 for why/how we originally added IPv6.
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#
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# Pass '4' or '6' as an argument to this function to specify
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# what type of address to get (IPv4, IPv6).
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target=8.8.8.8
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# For the IPv6 route, use the corresponding IPv6 address
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# of Google Public DNS. Again, it doesn't matter so long
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# as it's an address on the public Internet.
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if [ "$1" == "6" ]; then target=2001:4860:4860::8888; fi
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ip -$1 -o route get $target \
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| grep -v unreachable \
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| sed "s/.* src \([^ ]*\).*/\1/"
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}
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function ufw_allow {
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if [ -z "$DISABLE_FIREWALL" ]; then
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# ufw has completely unhelpful output
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ufw allow $1 > /dev/null;
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fi
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}
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function restart_service {
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hide_output service $1 restart
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}
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