docker-mailserver/target/scripts/helper-functions.sh
Georg Lauterbach ec8b99335e
Add changedetector functionality for ${SSL_TYPE} == manual (#2404)
Now, setups that use `SSL_TYPE=manual` will profit from the changedetector as well. Certificate changes are picked up and properly propagated.
2022-02-18 11:29:51 +01:00

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Executable file

#! /bin/bash
# TODO this file may be split up in the future
# into separate files under `target/scripts/helper/`
# which is a more fitting place
# These helpers are used by `setup-stack.sh` and `check-for-changes.sh`,
# not by anything within `helper-functions.sh` itself:
# shellcheck source=target/scripts/helpers/index.sh
. /usr/local/bin/helpers/index.sh
DMS_DEBUG="${DMS_DEBUG:=0}"
SCRIPT_NAME="$(basename "$0")" # This becomes the sourcing script name (Example: check-for-changes.sh)
LOCK_ID="$(uuid)" # Used inside of lock files to identify them and prevent removal by other instances of docker-mailserver
# file storing the checksums of the monitored files.
# shellcheck disable=SC2034
CHKSUM_FILE=/tmp/docker-mailserver-config-chksum
# ? --------------------------------------------- BIN HELPER
function errex
{
echo -e "Error :: ${*}\nAborting." >&2
exit 1
}
# `dms_panic` methods are appropriate when the type of error is a not recoverable,
# or needs to be very clear to the user about misconfiguration.
#
# Method is called with args:
# PANIC_TYPE => (Internal value for matching). You should use the convenience methods below based on your panic type.
# PANIC_INFO => Provide your own message string to insert into the error message for that PANIC_TYPE.
# PANIC_SCOPE => Optionally provide a string for debugging to better identify/locate the source of the panic.
function dms_panic
{
local PANIC_TYPE=${1}
local PANIC_INFO=${2}
local PANIC_SCOPE=${3} #optional
local SHUTDOWN_MESSAGE
case "${PANIC_TYPE:-}" in
( 'fail-init' ) # PANIC_INFO == <name of service or process that failed to start / initialize>
SHUTDOWN_MESSAGE="Failed to start ${PANIC_INFO}!"
;;
( 'no-env' ) # PANIC_INFO == <ENV VAR name>
SHUTDOWN_MESSAGE="Environment Variable: ${PANIC_INFO} is not set!"
;;
( 'no-file' ) # PANIC_INFO == <invalid filepath>
SHUTDOWN_MESSAGE="File ${PANIC_INFO} does not exist!"
;;
( 'misconfigured' ) # PANIC_INFO == <something possibly misconfigured, eg an ENV var>
SHUTDOWN_MESSAGE="${PANIC_INFO} appears to be misconfigured, please verify."
;;
( 'invalid-value' ) # PANIC_INFO == <an unsupported or invalid value, eg in a case match>
SHUTDOWN_MESSAGE="Invalid value for ${PANIC_INFO}!"
;;
( * ) # `dms_panic` was called directly without a valid PANIC_TYPE
SHUTDOWN_MESSAGE='Something broke :('
;;
esac
if [[ -n ${PANIC_SCOPE:-} ]]
then
_shutdown "${PANIC_SCOPE} | ${SHUTDOWN_MESSAGE}"
else
_shutdown "${SHUTDOWN_MESSAGE}"
fi
}
# Convenience wrappers based on type:
function dms_panic__fail_init { dms_panic 'fail-init' "${1}" "${2}"; }
function dms_panic__no_env { dms_panic 'no-env' "${1}" "${2}"; }
function dms_panic__no_file { dms_panic 'no-file' "${1}" "${2}"; }
function dms_panic__misconfigured { dms_panic 'misconfigured' "${1}" "${2}"; }
function dms_panic__invalid_value { dms_panic 'invalid-value' "${1}" "${2}"; }
function escape
{
echo "${1//./\\.}"
}
function create_lock
{
LOCK_FILE="/tmp/docker-mailserver/${SCRIPT_NAME}.lock"
while [[ -e "${LOCK_FILE}" ]]
do
_notify 'warn' "Lock file ${LOCK_FILE} exists. Another ${SCRIPT_NAME} execution is happening. Trying again shortly..."
# Handle stale lock files left behind on crashes
# or premature/non-graceful exits of containers while they're making changes
if [[ -n "$(find "${LOCK_FILE}" -mmin +1 2>/dev/null)" ]]
then
_notify 'warn' "Lock file older than 1 minute. Removing stale lock file."
rm -f "${LOCK_FILE}"
_notify 'inf' "Removed stale lock ${LOCK_FILE}."
fi
sleep 5
done
trap remove_lock EXIT
echo "${LOCK_ID}" > "${LOCK_FILE}"
}
function remove_lock
{
LOCK_FILE="${LOCK_FILE:-"/tmp/docker-mailserver/${SCRIPT_NAME}.lock"}"
[[ -z "${LOCK_ID}" ]] && errex "Cannot remove ${LOCK_FILE} as there is no LOCK_ID set"
if [[ -e "${LOCK_FILE}" ]] && grep -q "${LOCK_ID}" "${LOCK_FILE}" # Ensure we don't delete a lock that's not ours
then
rm -f "${LOCK_FILE}"
_notify 'inf' "Removed lock ${LOCK_FILE}."
fi
}
# ? --------------------------------------------- IP & CIDR
function _mask_ip_digit
{
if [[ ${1} -ge 8 ]]
then
MASK=255
elif [[ ${1} -le 0 ]]
then
MASK=0
else
VALUES=(0 128 192 224 240 248 252 254 255)
MASK=${VALUES[${1}]}
fi
local DVAL=${2}
((DVAL&=MASK))
echo "${DVAL}"
}
# Transforms a specific IP with CIDR suffix
# like 1.2.3.4/16 to subnet with cidr suffix
# like 1.2.0.0/16.
# Assumes correct IP and subnet are provided.
function _sanitize_ipv4_to_subnet_cidr
{
local DIGIT_PREFIX_LENGTH="${1#*/}"
declare -a MASKED_DIGITS DIGITS
IFS='.' ; read -r -a DIGITS < <(echo "${1%%/*}") ; unset IFS
for ((i = 0 ; i < 4 ; i++))
do
MASKED_DIGITS[i]=$(_mask_ip_digit "${DIGIT_PREFIX_LENGTH}" "${DIGITS[i]}")
DIGIT_PREFIX_LENGTH=$((DIGIT_PREFIX_LENGTH - 8))
done
echo "${MASKED_DIGITS[0]}.${MASKED_DIGITS[1]}.${MASKED_DIGITS[2]}.${MASKED_DIGITS[3]}/${1#*/}"
}
export -f _sanitize_ipv4_to_subnet_cidr
# ? --------------------------------------------- Notifications
function _notify
{
{ [[ -z ${1:-} ]] || [[ -z ${2:-} ]] ; } && return 0
local RESET LGREEN LYELLOW LRED RED LBLUE LGREY LMAGENTA
RESET='\e[0m' ; LGREEN='\e[92m' ; LYELLOW='\e[93m'
LRED='\e[31m' ; RED='\e[91m' ; LBLUE='\e[34m'
LGREY='\e[37m' ; LMAGENTA='\e[95m'
case "${1}" in
'tasklog' ) echo "-e${3:-}" "[ ${LGREEN}TASKLOG${RESET} ] ${2}" ;;
'warn' ) echo "-e${3:-}" "[ ${LYELLOW}WARNING${RESET} ] ${2}" ;;
'err' ) echo "-e${3:-}" "[ ${LRED}ERROR${RESET} ] ${2}" ;;
'fatal' ) echo "-e${3:-}" "[ ${RED}FATAL${RESET} ] ${2}" ;;
'inf' ) [[ ${DMS_DEBUG} -eq 1 ]] && echo "-e${3:-}" "[[ ${LBLUE}INF${RESET} ]] ${2}" ;;
'task' ) [[ ${DMS_DEBUG} -eq 1 ]] && echo "-e${3:-}" "[[ ${LGREY}TASKS${RESET} ]] ${2}" ;;
* ) echo "-e${3:-}" "[ ${LMAGENTA}UNKNOWN${RESET} ] ${2}" ;;
esac
return 0
}
export -f _notify
# ? --------------------------------------------- General
# Outputs the DNS label count (delimited by `.`) for the given input string.
# Useful for determining an FQDN like `mail.example.com` (3), vs `example.com` (2).
function _get_label_count
{
awk -F '.' '{ print NF }' <<< "${1}"
}
# Sets HOSTNAME and DOMAINNAME globals used throughout the scripts,
# and any subprocesses called that intereact with it.
function _obtain_hostname_and_domainname
{
# Normally this value would match the output of `hostname` which mirrors `/proc/sys/kernel/hostname`,
# However for legacy reasons, the system ENV `HOSTNAME` was replaced here with `hostname -f` instead.
#
# TODO: Consider changing to `DMS_FQDN`; a more accurate name, and removing the `export`, assuming no
# subprocess like postconf would be called that would need access to the same value via `$HOSTNAME` ENV.
#
# TODO: `OVERRIDE_HOSTNAME` was introduced for non-Docker runtimes that could not configure an explicit hostname.
# k8s was the particular runtime in 2017. This does not update `/etc/hosts` or other locations, thus risking
# inconsistency with expected behaviour. Investigate if it's safe to remove support. (--net=host also uses this as a workaround)
export HOSTNAME="${OVERRIDE_HOSTNAME:-$(hostname -f)}"
# If the container is misconfigured.. `hostname -f` (which derives it's return value from `/etc/hosts` or DNS query),
# will result in an error that returns an empty value. This warrants a panic.
if [[ -z ${HOSTNAME} ]]
then
dms_panic__misconfigured 'obtain_hostname' '/etc/hosts'
fi
# If the `HOSTNAME` is more than 2 labels long (eg: mail.example.com),
# We take the FQDN from it, minus the 1st label (aka _short hostname_, `hostname -s`).
#
# TODO: For some reason we're explicitly separating out a domain name from our FQDN,
# `hostname -d` was probably not the correct command for this intention either.
# Needs further investigation for relevance, and if `/etc/hosts` is important for consumers
# of this variable or if a more deterministic approach with `cut` should be relied on.
if [[ $(_get_label_count "${HOSTNAME}") -gt 2 ]]
then
if [[ -n ${OVERRIDE_HOSTNAME} ]]
then
# Emulates the intended behaviour of `hostname -d`:
# Assign the HOSTNAME value minus everything up to and including the first `.`
DOMAINNAME=${HOSTNAME#*.}
else
# Operates on the FQDN returned from querying `/etc/hosts` or fallback DNS:
#
# Note if you want the actual NIS `domainname`, use the `domainname` command,
# or `cat /proc/sys/kernel/domainname`.
# Our usage of `domainname` is under consideration as legacy, and not advised
# going forward. In future our docs should drop any mention of it.
#shellcheck disable=SC2034
DOMAINNAME="$(hostname -d)"
fi
fi
# Otherwise we assign the same value (eg: example.com):
# Not an else statement in the previous conditional in the event that `hostname -d` fails.
DOMAINNAME="${DOMAINNAME:-${HOSTNAME}}"
}
# Check if string input is an empty line, only whitespaces or `#` as the first non-whitespace character.
function _is_comment
{
grep -q -E "^\s*$|^\s*#" <<< "${1}"
}
# Call this method when you want to panic (emit a 'FATAL' log level error, and exit uncleanly).
# `dms_panic` methods should be preferred if your failure type is supported.
function _shutdown
{
local FATAL_ERROR_MESSAGE=$1
_notify 'fatal' "${FATAL_ERROR_MESSAGE}"
_notify 'err' "Shutting down.."
kill 1
}