backup

#!/bin/sh -l


## configure threads
threads=$(nproc || cat /proc/cpuinfo | grep -c 'core id')
[ -z "$threads" ] && threads=2

## load variables
. /etc/profile
set -a; . /etc/conf.d/dup 2>/dev/null; set +a

## checks
set -e # stop errors after sourcing dup config which can have unset vars
type dup 1>/dev/null || { echo "error: backup tool not found on system!"; exit 1; }
cd /opt/dup/repo || { echo "error: backup repository not found!"; exit 1; }
# clear known_hosts since it causes connections timeouts
[ -e .duplicacy/known_hosts ] && rm .duplicacy/known_hosts

max_runtime=${DUP_MAX_RUNTIME:-3600} # in seconds
storage=${STORAGE_NAME:-default}
dup_prune_args="-keep 0:7 -threads $threads -storage $storage"

with_timeout() {
    timeout --foreground $max_runtime $@
}

consul_check() {
    which consul &> /dev/null || { echo "consul not found."; false; }
}

## first prune
with_timeout dup prune $dup_prune_args
with_timeout dup check -fossils -resurrect -persist -threads $threads -storage $storage

# Do exclusive pruning to permanently delete chunks from remote
# It should only be enabled on very few hosts
if [ -n "$DUP_PRUNE_EXCL" ]; then
    if consul_check; then
        consul lock -shell backup '{
            set -e
            get_running() { running=$(consul kv get -recurse backup/running); n_running=$(echo -n "$running" | wc -l); }
            get_running
            while true; do
                [ "$n_running" -eq 0 ] && break
                now=$(date +%s)
                for b in $running; do
                    id=${b/:*}
                    start=${b/*:}
                    # this clears stale backups according to defined max_runtime
                    runtime=$((now-start))
                    echo "backup from ${id/backup\/running\/} running for $runtime seconds."
                    if [ $runtime -gt '"$max_runtime"' ]; then
                        consul kv delete $id
                    fi
                done
                get_running
                echo "waiting for $n_running backups to complete."
                sleep 5
            done
            # once no backups are running, execute exclusive pruning
            dup prune '"$dup_prune_args"' -a -exhaustive -exclusive
        }'
    fi
fi

# This prevents running backups during exclusive pruning
# set $DUP_NO_LOCKING to disable it
if [ -z "$DUP_NO_LOCKING" ] && consul_check; then
    id=${LOCA:-${IPv4:-$(ip a | grep inet | grep global | awk "{print \$2}")}}
    now=$(date +%s)
    [ -z "$id" ] && id="$(hostname)-$now"
    trap "consul kv delete backup/running/$id" EXIT TERM
    consul lock backup consul kv put backup/running/$id $now
fi

with_timeout dup backup -stats -threads $threads -storage $storage