docker-mailserver/target/scripts/helpers/lock.sh
Georg Lauterbach b9dbec3276
scripts: refactored scripts located under target/bin/ (#2500)
* refactored scripts located under `target/bin/`

The scripts under `target/bin/` now use the new log and I replaced some
`""` with `''` on the way. The functionality stays the same, this mostly
style and log.

* corrected fail2ban (script and tests)

* corrected OpenDKIM log output in tests

* reverted (some) changes to `sedfile`

Moreover, a few messages for BATS were streamlined and a regression in
the linting script reverted.

* apple PR feedback

* improve log output from `fail2ban` script

The new output has a single, clear message with the '[  ERROR  ]  '
prefix, and then output that explains the error afterwards. This is
coherent with the logging style which should be used while providing
more information than just a single line about IPTables not functioning.

* simplified `setquota` script

* consistently named the `__usage` function

Before, scripts located under `target/bin/` were using `usage` or
`__usage`. Now, they're using `__usage` as they should.

* improved `sedfile`

With `sedfile`, we cannot use the helper functions in a nice way because
it is used early in the Dockerfile at a stage where the helper scripts
are not yet copied. The script has been adjusted to be canonical with
all the other scripts under `target/bin/`.

* fixed tests

* removed `__usage` from places where it does not belong

`__usage` is to be used on wrong user input, not on other failures as
well. This was fixed in `delquota` and `setquota`.

* apply PR review feedback
2022-03-26 09:30:09 +01:00

41 lines
1.3 KiB
Bash

#! /bin/bash
# This becomes the sourcing script name
# (example: check-for-changes.sh)
SCRIPT_NAME="$(basename "$0")"
# Used inside of lock files to identify them and
# prevent removal by other instances of docker-mailserver
LOCK_ID="$(uuid)"
function _create_lock
{
LOCK_FILE="/tmp/docker-mailserver/${SCRIPT_NAME}.lock"
while [[ -e "${LOCK_FILE}" ]]
do
_log 'warn' "Lock file '${LOCK_FILE}' exists - another execution of '${SCRIPT_NAME}' 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
_log 'warn' 'Lock file older than 1 minute - removing stale lock file'
rm -f "${LOCK_FILE}"
fi
sleep 5
done
trap _remove_lock EXIT
_log 'trace' "Creating lock '${LOCK_FILE}'"
echo "${LOCK_ID}" >"${LOCK_FILE}"
}
function _remove_lock
{
LOCK_FILE="${LOCK_FILE:-"/tmp/docker-mailserver/${SCRIPT_NAME}.lock"}"
[[ -z "${LOCK_ID}" ]] && _exit_with_error "Cannot remove '${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}"
_log 'trace' "Removed lock '${LOCK_FILE}'"
fi
}