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