bup-backup-sync/bup-sync-trigger.sh

#!/bin/bash -e

# Parse CLI and set options
repoFile="$(dirname "$0")/repos"
dryRun=''
preventSleep=''
suspend=''

varDir=/var/lib/bup-backup-trigger
triggerFile="$varDir/trigger"
lockFile="$varDir/lock"
log="/var/log/bup-sync.log"

mkdir -p "$varDir"

while [ $# -gt 0 ]
do
    case "$1" in
        --repos|-r)
            repoFile="$2"
            shift
            ;;
        --dry|--dry-run|-d)
            dryRun=y
            ;;
        --lock)
            touch "$lockFile"
            exit 0
            ;;
        --unlock)
            rm -f "$lockFile"
            exit 0
            ;;
        --no-sleep)
            preventSleep=y
            ;;
        --suspend)
            suspend=y
            ;;
        --log)
            log="$2"
            shift
            ;;
        *)
            echo "Cannot understand parameter \"$1\". Aborting." >&2
            exit 1
            ;;
    esac
    shift
done

if [ "$log" != '-' ]
then
    exec >> "$log"
fi

# Do some safety checks

if [ ! -r "$repoFile" ]
then
    echo "Cannot read the file $repoFile. Exiting" >&2
    exit 1
fi

# if [ -f "$lockFile" ]
# then
#     echo "The lock file exists. Skipping for now ($(date))"
#     exit 0
# fi

# Define the needed functions

getNextDate() {
    python << EOF
import datetime

now = datetime.date.today()
weekday = now.weekday()
oneDay = datetime.timedelta(days=1)
mondayThisWeek = now - oneDay * weekday
mondayNextWeek = mondayThisWeek + oneDay * 7
dt = datetime.datetime.fromisoformat(mondayNextWeek.isoformat())
dt = dt.replace(hour=4, minute=45)
print(int(dt.astimezone(datetime.timezone.utc).timestamp()))
EOF
}

updateTriggerFile() {
    getNextDate > "$triggerFile"
}

triggerLiesInPast() {
    if [ ! -f "$triggerFile" ]
    then
        return 0
    fi

    local now=$(date +%s)
    local triggered=$(cat "$triggerFile")
    if [ $now -gt "$triggered" ]
    then
        return 0
    else
        return 1
    fi
}

getNextStart() {
    date -d "@$(cat "$triggerFile")" "+%Y-%m-%d %H:%M"
}

goToSleep() {
    nextStart=$(getNextStart)
    echo "Going to sleep until $nextStart"
    rtcwake --mode disk --date "$nextStart"
}

if ! triggerLiesInPast
then
    echo "The timestamp in the trigger event lies in the future. Waiting further."
    exit 0
fi

if [ -n "$suspend" ]
then
    if [ -f "$lockFile" -o -n "$preventSleep" ]
    then
        echo "Failed to go to sleep while lock file is present or sleep prevention given."
        exit 1
    else
        goToSleep
        exit 0
    fi
fi

echo "The backup script is triggered."

while read line
do
    echo "Processing line $line"
    if [ -n "$dryRun" ]
    then
        echo "Shipping to call script $line as in dry mode."
    else
        $line
    fi
done <<< $(cat "$repoFile" | grep -v '^#' | sed '/^\W*$/d')

if [ -n "$dryRun" ]
then
    echo "Not updating the trigger timestamp. The value would be $(getNextDate)."
    echo "Sleep mode entry is skipped as well."
else
    updateTriggerFile

    if [ -n "$preventSleep" ]
    then
        echo "Not going to sleep as prevented by CLI argument"
    else
        if [ -f "$lockFile" ]
        then
            echo "Skipping sleeping due to lock file existence."
        else
            goToSleep
        fi
    fi
fi