Created
January 4, 2019 01:17
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Lock File Management Script
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| #!/bin/bash | |
| [[ -z $1 ]] && echo "Usage: \"$0\" [sleep interval in seconds]" && exit 99 | |
| LOCKFILE=/tmp/.${0##*/}.exclusivelock | |
| SLEEP_INTERVAL=$1 | |
| WAIT=30 | |
| declare -A LOCK_FDS=() | |
| lock() { | |
| local OP=$1 | |
| local FILE=$(readlink -f "$2") | |
| case ${OP} in | |
| quick) | |
| [[ -f ${FILE} ]] && return 1 | |
| local LOCKFD | |
| exec {LOCKFD}>"${FILE}" | |
| flock -xn "${LOCKFD}" -c 'echo "Lock Acquired"' | |
| trap "cleanup_lock ${FILE}" exit | |
| LOCK_FDS[${FILE}]=${LOCKFD} | |
| ;; | |
| shared) | |
| [[ -f ${FILE} ]] && return 1 | |
| local LOCKFD | |
| exec {LOCKFD}>${FILE} | |
| flock -s "${LOCKFD}" -c 'echo "Shared Lock Acquired"' | |
| trap "cleanup_lock ${FILE}" exit | |
| LOCK_FDS[${FILE}]=${LOCKFD} | |
| ;; | |
| hold) | |
| [[ -f ${FILE} ]] && return 1 | |
| local LOCKFD | |
| exec {LOCKFD}>${FILE} | |
| flock -x "${LOCKFD}" -c 'echo "Lock Acquired"' | |
| trap "cleanup_lock ${FILE}" exit | |
| LOCK_FDS[${FILE}]=${LOCKFD} | |
| ;; | |
| wait) | |
| [[ -f ${FILE} ]] && return 1 | |
| local LOCKFD | |
| exec {LOCKFD}>${FILE} | |
| flock -w ${WAIT} "${LOCKFD}" -c 'echo "Lock Acquired"' | |
| trap "cleanup_lock ${FILE}" exit | |
| LOCK_FDS[${FILE}]=${LOCKFD} | |
| ;; | |
| esac | |
| } | |
| cleanup_lock() { | |
| local FILE=$(readlink -f "$1") | |
| flock -u ${LOCK_FDS[${FILE}]} | |
| flock -xn ${LOCK_FDS[${FILE}]} | |
| rm -f ${FILE} | |
| } | |
| unlock() { | |
| local FILE=$(readlink -f "$1") | |
| [[ -f ${FILE} ]] || return | |
| exec ${LOCK_FDS[${FILE}]}>&- | |
| unset ${LOCK_FDS[${FILE}]} | |
| } | |
| lock quick ${LOCKFILE} || exit $? | |
| while true; do | |
| sleep $((${SLEEP_INTERVAL} - $(date +%s) % ${SLEEP_INTERVAL})) | |
| echo "Running: $(date +%s)" | |
| done |
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