41 lines
1.3 KiB
Bash
41 lines
1.3 KiB
Bash
#!/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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_log 'warn' "Lock file '${LOCK_FILE}' exists - another execution of '${SCRIPT_NAME}' 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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_log 'warn' 'Lock file older than 1 minute - removing stale lock file'
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rm -f "${LOCK_FILE}"
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fi
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sleep 5
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done
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trap _remove_lock EXIT
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_log 'trace' "Creating lock '${LOCK_FILE}'"
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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 "${LOCK_ID}" ]] && _exit_with_error "Cannot remove '${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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_log 'trace' "Removed lock '${LOCK_FILE}'"
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fi
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}
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