alpine-overlay/kubezero/zdt-base/cb_lock.sh

68 lines
1.2 KiB
Bash
Raw Normal View History

MUTEX=mutex
MUTEX_OWNER=$HOSTNAME
MUTEX_TIMEOUT=600
release_lock() {
local S3LOCK=$1
rm -f $MUTEX
aws s3 rm $S3LOCK
}
# Lock not timed out and we own it: 0
# Lock not timed out and someone else owns it: 1
# Lock timed out: 2
verify_lock() {
local S3LOCK=$1
aws s3 cp $S3LOCK $MUTEX
_host=$(grep "MUTEX_OWNER=" $MUTEX | sed -e 's/MUTEX_OWNER=//')
_time=$(grep "MUTEX_TIME=" $MUTEX | sed -e 's/MUTEX_TIME=//')
# Check for timestamp and timeout
let timepassed=$(date -u +%s)-$_time
[ $timepassed -gt $MUTEX_TIMEOUT ] && return 2
[ "$_host" == "$MUTEX_OWNER" ] && return 0
return 1
}
aquire_lock() {
local S3LOCK=$1
echo "MUTEX_OWNER=${MUTEX_OWNER}" > $MUTEX
echo "MUTEX_TIME=$(date -u +%s)" >> $MUTEX
aws s3 cp $MUTEX $S3LOCK
# verify we actually got the lock
sleep 2
verify_lock $S3LOCK
}
check_lock() {
local S3LOCK=$1
aws s3 ls $S3LOCK && rc=$? || rc=$?
# No LOCK ? -> get it !
if [ $rc -ne 0 ]; then
aquire_lock $S3LOCK
else
verify_lock $S3LOCK && rc=$? || rc=$?
# Lock timeout -> we get it
if [ $rc -eq 2 ]; then
aquire_lock $S3LOCK
# we already own it
elif [ $rc -eq 0 ]; then
return 0
# someone else has a valid lock
else
return 1
fi
fi
}