#!/bin/bash

# Ansible managed

error_exit() {
    printf "%s\n" "$1"
    exit 1
}

RESTIC_ETC_PATH=${RESTIC_ETC_PATH:-/etc/restic}
LOCK_PATH=/run/restic

# shellcheck source=/dev/null
source "${RESTIC_ETC_PATH}/env.sh"

KEEP_LOCK=
MAX_ATTEMPTS=60
NICE="ionice -c2 nice -n19"
JOB=$1
LOCK="/run/restic/${JOB}.lock"

function finish {
    if [ -z $KEEP_LOCK ]; then
        rm -f "$LOCK"
    fi
}
trap finish EXIT

if [ ! -d $LOCK_PATH ]; then
    mkdir $LOCK_PATH
fi

if [ -z "$JOB" ]; then
    error_exit "job is missing"
fi

JOB_PATH="${RESTIC_ETC_PATH}/jobs/${JOB}"
JOB_ENV="${JOB_PATH}/env.sh"
HOOKS_PATH="${JOB_PATH}/hooks.d"

if [ ! -r "$JOB_ENV" ]; then
    error_exit "${JOB_ENV} does not exist"
fi

# shellcheck disable=SC1090
. "$JOB_ENV"

if [ -z "${REPO+x}" ]; then
    error_exit "\$REPO is not set"
fi

REPO_PATH="${RESTIC_ETC_PATH}/repos/${REPO}"
REPO_ENV="${REPO_PATH}/env.sh"

if [ ! -r "$REPO_ENV" ]; then
    error_exit "${REPO_ENV} does not exist"
fi

# shellcheck disable=SC1090
. "$REPO_ENV"

EXCLUDE_PATH="${JOB_PATH}/exclude.txt"

if [ -z "${PATHS+x}" ]; then
    error_exit "\$PATHS is not set"
fi

START="$(date +%s)"

if [ -f "$LOCK" ]; then
    pid=$(cat "$LOCK")
    if ! kill -0 "$pid" 2> /dev/null; then
        printf "removing orphaned lock, pid %d does not exist\n" "$pid"
        rm -f "$LOCK"
    else
        if [[ -f "/proc/${pid}/cmdline" ]]; then
            cmdline=$(tr "\0" " " <"/proc/${pid}/cmdline")
            if ! [[ $cmdline =~ $(basename "$0") ]]; then
                printf "removing orphaned lock, pid %d belongs to another process\n" "$pid"
                rm -f "$LOCK"
            else
                KEEP_LOCK=1
                error_exit "another job is running, pid=${pid}"
            fi
        fi
    fi
fi

echo $$ > "$LOCK"

LOCKED=$(($(date +%s) - START))

printf "job '%s' started\n" "$JOB"

if [ -d "${HOOKS_PATH}" ]; then
    printf "running '%s' job pre-hooks\n" "$JOB"
    if ! run-parts --exit-on-error -v -a pre "${HOOKS_PATH}"; then
        printf "'%s' pre-hooks failed, running post-hooks and exiting\n" "$JOB"
        run-parts --exit-on-error -v -a post "${HOOKS_PATH}"
        exit 1
    fi
fi

counter=0
sleep=1
rc=1

printf "restic started\n"
until [ $counter -eq "$MAX_ATTEMPTS" ] || [ $rc -eq 0 ]; do
    if [ -r "$EXCLUDE_PATH" ]; then
        $NICE "$RESTIC_PATH" backup -q --exclude-file="${EXCLUDE_PATH}" "${PATHS}"
    else
        $NICE "$RESTIC_PATH" backup -q "${PATHS}"
    fi

    rc=$?

    if [ $rc -eq 0 ]; then
        break
    else
        sleep=$((counter * 5))
        printf "sleeping for %d seconds (%d)\n" $sleep $counter
        sleep $sleep
    fi

    (( counter++ ))
done
printf "restic complete\n"

if [ $rc -ne 0 ] && [ $counter -eq "$MAX_ATTEMPTS" ]; then
  printf "restic job timed out, exiting\n"
else
    printf "job '%s' complete\n" "$JOB"
fi

if [ -d "${HOOKS_PATH}" ]; then
    printf "running '%s' job post-hooks\n" "$JOB"
    run-parts --exit-on-error -v -a post "${HOOKS_PATH}"
fi

END=$(date +%s)

if [ -d /var/spool/node_exporter/textfile_collector ]; then
    cat << EOF > "/var/spool/node_exporter/textfile_collector/restic.prom.$$"
node_restic_duration_seconds{restic_job="${JOB}"} $((END - START))
node_restic_lock_duration_seconds{restic_job="${JOB}"} $LOCKED
node_restic_last_run_time{restic_job="${JOB}"} $END
node_restic_retries{restic_job="${JOB}"} $counter
EOF

    if [ -f /var/spool/node_exporter/textfile_collector/restic.prom ]; then
        cat /var/spool/node_exporter/textfile_collector/restic.prom "/var/spool/node_exporter/textfile_collector/restic.prom.$$" |
        tac |
        awk '!seen[$1]++' |
        tac |
        sponge "/var/spool/node_exporter/textfile_collector/restic.prom.$$"
    fi

    mv "/var/spool/node_exporter/textfile_collector/restic.prom.$$" \
      /var/spool/node_exporter/textfile_collector/restic.prom
fi