40 lines
1.3 KiB
Bash
40 lines
1.3 KiB
Bash
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#! /bin/bash
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# This becomes the sourcing script name
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# (example: check-for-changes.sh)
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SCRIPT_NAME="$(basename "$0")"
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# Used inside of lock files to identify them and
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# prevent removal by other instances of docker-mailserver
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LOCK_ID="$(uuid)"
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function _create_lock
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{
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LOCK_FILE="/tmp/docker-mailserver/${SCRIPT_NAME}.lock"
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while [[ -e "${LOCK_FILE}" ]]
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do
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_notify 'warn' "Lock file ${LOCK_FILE} exists. Another ${SCRIPT_NAME} execution is happening. Trying again shortly..."
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# Handle stale lock files left behind on crashes
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# or premature/non-graceful exits of containers while they're making changes
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if [[ -n "$(find "${LOCK_FILE}" -mmin +1 2>/dev/null)" ]]
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then
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_notify 'warn' "Lock file older than 1 minute. Removing stale lock file."
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rm -f "${LOCK_FILE}"
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_notify 'inf' "Removed stale lock ${LOCK_FILE}."
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fi
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sleep 5
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done
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trap _remove_lock EXIT
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echo "${LOCK_ID}" > "${LOCK_FILE}"
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}
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function _remove_lock
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{
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LOCK_FILE="${LOCK_FILE:-"/tmp/docker-mailserver/${SCRIPT_NAME}.lock"}"
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[[ -z "${LOCK_ID}" ]] && _errex "Cannot remove ${LOCK_FILE} as there is no LOCK_ID set"
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if [[ -e "${LOCK_FILE}" ]] && grep -q "${LOCK_ID}" "${LOCK_FILE}" # Ensure we don't delete a lock that's not ours
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then
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rm -f "${LOCK_FILE}"
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_notify 'inf' "Removed lock ${LOCK_FILE}."
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fi
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}
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