#!/bin/bash
#
# Script Evobackup client
# See https://gitea.evolix.org/evolix/evobackup
#
# Authors: Evolix <info@evolix.fr>,
#          Gregory Colpart <reg@evolix.fr>,
#          Romain Dessort <rdessort@evolix.fr>,
#          Benoit Série <bserie@evolix.fr>,
#          Tristan Pilat <tpilat@evolix.fr>,
#          Victor Laborie <vlaborie@evolix.fr>,
#          Jérémy Lecour <jlecour@evolix.fr>
#          and others.
#
# Licence: AGPLv3
#
# /!\ DON'T FORGET TO SET "MAIL" and "SERVERS" VARIABLES

##### Configuration ###################################################

VERSION="22.12"

# email adress for notifications
MAIL=jdoe@example.com

# list of hosts (hostname or IP) and SSH port for Rsync
SERVERS="node0.backup.example.com:2XXX node1.backup.example.com:2XXX"

# explicit PATH
PATH=/sbin:/usr/sbin:/bin:/usr/bin:/usr/local/sbin:/usr/local/bin

# Should we fallback on other servers when the first one is unreachable?
SERVERS_FALLBACK=${SERVERS_FALLBACK:-1}

# timeout (in seconds) for SSH connections
SSH_CONNECT_TIMEOUT=${SSH_CONNECT_TIMEOUT:-90}

# We use /home/backup : feel free to use your own dir
LOCAL_BACKUP_DIR="/home/backup"

# You can set "linux" or "bsd" manually or let it choose automatically
SYSTEM=$(uname | tr '[:upper:]' '[:lower:]')

# Store pid in a file named after this program's name
PROGNAME=$(basename "$0")
PIDFILE="/var/run/${PROGNAME}.pid"

# Customize the log path if you have multiple scripts and with separate logs
LOGFILE="/var/log/evobackup.log"

# Full Rsync log file, reset each time
RSYNC_LOGFILE="/var/log/${PROGNAME}.rsync.log"

HOSTNAME=$(hostname)

DATE_FORMAT="%Y-%m-%d %H:%M:%S"

# Enable/disable local tasks (default: enabled)
: "${LOCAL_TASKS:=1}"
# Enable/disable sync tasks (default: enabled)
: "${SYNC_TASKS:=1}"

CANARY_FILE="/zzz_evobackup_canary"

# Source paths can be customized
# Empty lines, and lines containing # or ; are ignored
# NOTE: remember to single-quote paths if they contain globs (*)
#       and you want to defer expansion
RSYNC_INCLUDES="
/etc
/root
/var
/home
"

# Excluded paths can be customized
# Empty lines, and lines beginning with # or ; are ignored
# NOTE: remember to single-quote paths if they contain globs (*)
#       and you want to defer expansion
RSYNC_EXCLUDES="
/dev
/proc
/run
/sys
/tmp
/usr/doc
/usr/obj
/usr/share/doc
/usr/src
/var/apt
/var/cache
'/var/db/munin/*.tmp'
/var/lib/amavis/amavisd.sock
/var/lib/amavis/tmp
/var/lib/amavis/virusmails
'/var/lib/clamav/*.tmp'
/var/lib/elasticsearch
/var/lib/metche
/var/lib/mongodb
'/var/lib/munin/*tmp*'
/var/lib/mysql
/var/lib/php/sessions
/var/lib/php5
/var/lib/postgres
/var/lib/postgresql
/var/lib/sympa
/var/lock
/var/run
/var/spool/postfix
/var/spool/smtpd
/var/spool/squid
/var/state
/var/tmp
lost+found
'.nfs.*'
'lxc/*/rootfs/tmp'
'lxc/*/rootfs/usr/doc'
'lxc/*/rootfs/usr/obj'
'lxc/*/rootfs/usr/share/doc'
'lxc/*/rootfs/usr/src'
'lxc/*/rootfs/var/apt'
'lxc/*/rootfs/var/cache'
'lxc/*/rootfs/var/lib/php5'
'lxc/*/rootfs/var/lib/php/sessions'
'lxc/*/rootfs/var/lock'
'lxc/*/rootfs/var/run'
'lxc/*/rootfs/var/state'
'lxc/*/rootfs/var/tmp'
/home/mysqltmp
"


##### FUNCTIONS #######################################################

local_tasks() {
    log "START LOCAL_TASKS"

    # You can comment or uncomment sections below to customize the backup

    ## OpenLDAP : example with slapcat
    # slapcat -n 0 -l ${LOCAL_BACKUP_DIR}/config.ldap.bak
    # slapcat -n 1 -l ${LOCAL_BACKUP_DIR}/data.ldap.bak
    # slapcat -l ${LOCAL_BACKUP_DIR}/ldap.bak

    ## MySQL

    ## Purge previous dumps
    # rm -f  ${LOCAL_BACKUP_DIR}/mysql.*.gz
    # rm -rf ${LOCAL_BACKUP_DIR}/mysql
    # rm -rf ${LOCAL_BACKUP_DIR}/mysqlhotcopy
    # rm -rf /home/mysqldump
    # find ${LOCAL_BACKUP_DIR}/ -type f -name '*.err' -delete

    ## example with global and compressed mysqldump
    # mysqldump --defaults-extra-file=/etc/mysql/debian.cnf -P 3306 \
    #  --opt --all-databases --force --events --hex-blob 2> ${LOCAL_BACKUP_DIR}/mysql.bak.err | gzip --best > ${LOCAL_BACKUP_DIR}/mysql.bak.gz
    # last_rc=$?
    # if [ ${last_rc} -ne 0 ]; then
    #     error "mysqldump (global compressed) returned an error ${last_rc}, check ${LOCAL_BACKUP_DIR}/mysql.bak.err"
    #     rc=101
    # fi

    ## example with compressed SQL dump (with data) for each databases
    # mkdir -p -m 700 ${LOCAL_BACKUP_DIR}/mysql/
    # for i in $(mysql --defaults-extra-file=/etc/mysql/debian.cnf -P 3306 -e 'show databases' -s --skip-column-names \
    # | grep --extended-regexp --invert-match "^(Database|information_schema|performance_schema|sys)"); do
    #     mysqldump --defaults-extra-file=/etc/mysql/debian.cnf --force -P 3306 --events --hex-blob $i 2> ${LOCAL_BACKUP_DIR}/${i}.err | gzip --best > ${LOCAL_BACKUP_DIR}/mysql/${i}.sql.gz
    #     last_rc=$?
    #     if [ ${last_rc} -ne 0 ]; then
    #         error "mysqldump (${i} compressed) returned an error ${last_rc}, check ${LOCAL_BACKUP_DIR}/${i}.err"
    #         rc=102
    #     fi
    # done

    ## Dump all grants (requires 'percona-toolkit' package)
    # mkdir -p -m 700 ${LOCAL_BACKUP_DIR}/mysql/
    # pt-show-grants --flush --no-header 2> ${LOCAL_BACKUP_DIR}/mysql/all_grants.err > ${LOCAL_BACKUP_DIR}/mysql/all_grants.sql
    # last_rc=$?
    # if [ ${last_rc} -ne 0 ]; then
    #     error "pt-show-grants returned an error ${last_rc}, check ${LOCAL_BACKUP_DIR}/mysql/all_grants.err"
    #     rc=103
    # fi

    # Dump all variables
    # mysql -A -e"SHOW GLOBAL VARIABLES;" 2> ${LOCAL_BACKUP_DIR}/MySQLCurrentSettings.err > ${LOCAL_BACKUP_DIR}/MySQLCurrentSettings.txt
    # last_rc=$?
    # if [ ${last_rc} -ne 0 ]; then
    #     error "mysql (variables) returned an error ${last_rc}, check ${LOCAL_BACKUP_DIR}/MySQLCurrentSettings.err"
    #     rc=104
    # fi

    ## example with SQL dump (schema only, no data) for each databases
    # mkdir -p -m 700 ${LOCAL_BACKUP_DIR}/mysql/
    # for i in $(mysql --defaults-extra-file=/etc/mysql/debian.cnf -P 3306 -e 'show databases' -s --skip-column-names \
    # | grep --extended-regexp --invert-match "^(Database|information_schema|performance_schema|sys)"); do
    #     mysqldump --defaults-extra-file=/etc/mysql/debian.cnf --force -P 3306 --no-data --databases $i 2> ${LOCAL_BACKUP_DIR}/${i}.schema.err > ${LOCAL_BACKUP_DIR}/mysql/${i}.schema.sql
    #     last_rc=$?
    #     if [ ${last_rc} -ne 0 ]; then
    #         error "mysqldump (${i} schema) returned an error ${last_rc}, check ${LOCAL_BACKUP_DIR}/${i}.schema.err"
    #         rc=105
    #     fi
    # done

    ## example with *one* uncompressed SQL dump for *one* database (MYBASE)
    # mkdir -p -m 700 ${LOCAL_BACKUP_DIR}/mysql/MYBASE
    # chown -RL mysql ${LOCAL_BACKUP_DIR}/mysql/
    # mysqldump --defaults-extra-file=/etc/mysql/debian.cnf --force -Q \
    # --opt --events --hex-blob --skip-comments -T ${LOCAL_BACKUP_DIR}/mysql/MYBASE MYBASE 2> ${LOCAL_BACKUP_DIR}/mysql/MYBASE.err
    # last_rc=$?
    # if [ ${last_rc} -ne 0 ]; then
    #     error "mysqldump (MYBASE) returned an error ${last_rc}, check ${LOCAL_BACKUP_DIR}/mysql/MYBASE.err"
    #     rc=106
    # fi

    ## example with two dumps for each table (.sql/.txt) for all databases
    # for i in $(echo SHOW DATABASES | mysql --defaults-extra-file=/etc/mysql/debian.cnf -P 3306 \
    # | grep --extended-regexp --invert-match "^(Database|information_schema|performance_schema|sys)" ); do
    #     mkdir -p -m 700 /home/mysqldump/$i ; chown -RL mysql /home/mysqldump
    #     mysqldump --defaults-extra-file=/etc/mysql/debian.cnf --force -P 3306 -Q --opt --events --hex-blob --skip-comments \
    #  --fields-enclosed-by='\"' --fields-terminated-by=',' -T /home/mysqldump/$i $i 2> /home/mysqldump/$i.err"
    #     last_rc=$?
    #     if [ ${last_rc} -ne 0 ]; then
    #         error "mysqldump (${i} files) returned an error ${last_rc}, check /home/mysqldump/$i.err"
    #         rc=107
    #     fi
    # done

    ## example with mysqlhotcopy
    # mkdir -p -m 700 ${LOCAL_BACKUP_DIR}/mysqlhotcopy/
    # mysqlhotcopy MYBASE ${LOCAL_BACKUP_DIR}/mysqlhotcopy/ 2> ${LOCAL_BACKUP_DIR}/mysqlhotcopy/MYBASE.err
    # last_rc=$?
    # if [ ${last_rc} -ne 0 ]; then
    #     error "mysqlhotcopy returned an error ${last_rc}, check ${LOCAL_BACKUP_DIR}/mysqlhotcopy/MYBASE.err"
    #     rc=108
    # fi

    ## example for multiples MySQL instances
    # mysqladminpasswd=$(grep -m1 'password = .*' /root/.my.cnf|cut -d" " -f3)
    # grep --extended-regexp "^port\s*=\s*\d*" /etc/mysql/my.cnf | while read instance; do
    #     instance=$(echo "$instance"|awk '{ print $3 }')
    #     if [ "$instance" != "3306" ]
    #     then
    #         mysqldump -P $instance --opt --all-databases --hex-blob -u mysqladmin -p$mysqladminpasswd 2> ${LOCAL_BACKUP_DIR}/mysql.${instance}.err | gzip --best > ${LOCAL_BACKUP_DIR}/mysql.${instance}.bak.gz
    #         last_rc=$?
    #         if [ ${last_rc} -ne 0 ]; then
    #             error "mysqldump (instance ${instance}) returned an error ${last_rc}, check ${LOCAL_BACKUP_DIR}/mysql.${instance}.err"
    #             rc=107
    #         fi
    #     fi
    # done

    ## PostgreSQL

    ## Purge previous dumps
    # rm -rf ${LOCAL_BACKUP_DIR}/pg.*.gz
    # rm -rf ${LOCAL_BACKUP_DIR}/pg-backup.tar
    # rm -rf ${LOCAL_BACKUP_DIR}/postgresql/*

    ## example with pg_dumpall (warning: you need space in ~postgres)
    # su - postgres -c "pg_dumpall > ~/pg.dump.bak"
    # mv ~postgres/pg.dump.bak ${LOCAL_BACKUP_DIR}/

    ## another method with gzip directly piped
    # (
    #    cd /var/lib/postgresql;
    #    sudo -u postgres pg_dumpall | gzip > ${LOCAL_BACKUP_DIR}/pg.dump.bak.gz
    # )

    ## example with all tables from MYBASE excepts TABLE1 and TABLE2
    # pg_dump -p 5432 -h 127.0.0.1 -U USER --clean -F t --inserts -f ${LOCAL_BACKUP_DIR}/pg-backup.tar -t 'TABLE1' -t 'TABLE2' MYBASE

    ## example with only TABLE1 and TABLE2 from MYBASE
    # pg_dump -p 5432 -h 127.0.0.1 -U USER --clean -F t --inserts -f ${LOCAL_BACKUP_DIR}/pg-backup.tar -T 'TABLE1' -T 'TABLE2' MYBASE

    ## example with compressed PostgreSQL dump for each databases
    # mkdir -p -m 700 ${LOCAL_BACKUP_DIR}/postgresql
    # chown postgres:postgres ${LOCAL_BACKUP_DIR}/postgresql
    # (
    #    cd /var/lib/postgresql
    #    dbs=$(sudo -u postgres psql -U postgres -lt | awk -F\| '{print $1}' |grep -v template*)
    #    for databases in $dbs ; do sudo -u postgres /usr/bin/pg_dump --create -U postgres -d $databases | gzip --best -c > ${LOCAL_BACKUP_DIR}/postgresql/$databases.sql.gz ; done
    # )

    ## MongoDB

    ## don't forget to create use with read-only access
    ## > use admin
    ## > db.createUser( { user: "mongobackup", pwd: "PASS", roles: [ "backup", ] } )
    ## Purge previous dumps
    # rm -rf ${LOCAL_BACKUP_DIR}/mongodump/
    # mkdir -p -m 700 ${LOCAL_BACKUP_DIR}/mongodump/
    # mongodump --quiet -u mongobackup -pPASS -o ${LOCAL_BACKUP_DIR}/mongodump/
    # if [ $? -ne 0 ]; then
    #   echo "Error with mongodump!"
    # fi

    ## Redis

    ## Purge previous dumps
    # rm -rf ${LOCAL_BACKUP_DIR}/redis/
    # rm -rf ${LOCAL_BACKUP_DIR}/redis-*
    ## Copy dump.rdb file for each found instance
    # for instance in $(find /var/lib/ -mindepth 1 -maxdepth 1 '(' -type d -o -type l ')' -name 'redis*'); do
    #     if [ -f "${instance}/dump.rdb" ]; then
    #         name=$(basename $instance)
    #         mkdir -p ${LOCAL_BACKUP_DIR}/${name}
    #         cp -a "${instance}/dump.rdb" "${LOCAL_BACKUP_DIR}/${name}"
    #         gzip "${LOCAL_BACKUP_DIR}/${name}/dump.rdb"
    #     fi
    # done

    ## ElasticSearch

    ## Take a snapshot as a backup.
    ## Warning: You need to have a path.repo configured.
    ## See: https://wiki.evolix.org/HowtoElasticsearch#snapshots-et-sauvegardes
    # curl -s -XDELETE "localhost:9200/_snapshot/snaprepo/snapshot.daily" >> "${LOGFILE}"
    # curl -s -XPUT "localhost:9200/_snapshot/snaprepo/snapshot.daily?wait_for_completion=true" >> "${LOGFILE}"
    ## Clustered version here
    ## It basically the same thing except that you need to check that NFS is mounted
    # if ss | grep ':nfs' | grep -q 'ip\.add\.res\.s1' && ss | grep ':nfs' | grep -q 'ip\.add\.res\.s2'
    # then
    #     curl -s -XDELETE "localhost:9200/_snapshot/snaprepo/snapshot.daily" >> "${LOGFILE}"
    #     curl -s -XPUT "localhost:9200/_snapshot/snaprepo/snapshot.daily?wait_for_completion=true" >> "${LOGFILE}"
    # else
    #     echo 'Cannot make a snapshot of elasticsearch, at least one node is not mounting the repository.'
    # fi
    ## If you need to keep older snapshot, for example the last 10 daily snapshots, replace the XDELETE and XPUT lines by :
    # for snapshot in $(curl -s -XGET "localhost:9200/_snapshot/snaprepo/_all?pretty=true" | grep -Eo 'snapshot_[0-9]{4}-[0-9]{2}-[0-9]{2}' | head -n -10); do
    #     curl -s -XDELETE "localhost:9200/_snapshot/snaprepo/${snapshot}" | grep -v -Fx '{"acknowledged":true}'
    # done
    # date=$(/bin/date +%F)
    # curl -s -XPUT "localhost:9200/_snapshot/snaprepo/snapshot_${date}?wait_for_completion=true" >> "${LOGFILE}"

    ## RabbitMQ

    ## export config
    # rabbitmqadmin export ${LOCAL_BACKUP_DIR}/rabbitmq.config >> "${LOGFILE}"

    ## MegaCli config

    # megacli -CfgSave -f ${LOCAL_BACKUP_DIR}/megacli_conf.dump -a0 >/dev/null

    ## Dump network routes with mtr and traceroute (warning: could be long with aggressive firewalls)
    network_targets="8.8.8.8 www.evolix.fr travaux.evolix.net"
    mtr_bin=$(command -v mtr)
    if [ -n "${mtr_bin}" ]; then
        for addr in ${network_targets}; do
            ${mtr_bin} -r "${addr}" > "${LOCAL_BACKUP_DIR}/mtr-${addr}"
        done
    fi
    traceroute_bin=$(command -v traceroute)
    if [ -n "${traceroute_bin}" ]; then
        for addr in ${network_targets}; do
            ${traceroute_bin} -n "${addr}" > "${LOCAL_BACKUP_DIR}/traceroute-${addr}" 2>&1
        done
    fi

    server_state_dir="${LOCAL_BACKUP_DIR}/server-state"

    dump_server_state_bin=$(command -v dump-server-state)
    if [ -z "${dump_server_state_bin}" ]; then
        error "dump-server-state is missing"
        rc=1
    else
        if [ "${SYSTEM}" = "linux" ]; then
            ${dump_server_state_bin} --all --force --dump-dir "${server_state_dir}"
            last_rc=$?
            if [ ${last_rc} -ne 0 ]; then
                error "dump-server-state returned an error ${last_rc}, check ${server_state_dir}"
                rc=1
            fi
        else
            ${dump_server_state_bin} --all --force --dump-dir "${server_state_dir}"
            last_rc=$?
            if [ ${last_rc} -ne 0 ]; then
                error "dump-server-state returned an error ${last_rc}, check ${server_state_dir}"
                rc=1
            fi
        fi
    fi

    ## Dump rights
    # getfacl -R /var  > ${server_state_dir}/rights-var.txt
    # getfacl -R /etc  > ${server_state_dir}/rights-etc.txt
    # getfacl -R /usr  > ${server_state_dir}/rights-usr.txt
    # getfacl -R /home > ${server_state_dir}/rights-home.txt

    log "STOP LOCAL_TASKS"
}
build_rsync_main_cmd() {
    ###################################################################
    # /!\ WARNING /!\ WARNING /!\ WARNING /!\ WARNING /!\ WARNING /!\ #
    ###################################################################
    # DO NOT USE COMMENTS in rsync lines                              #
    # DO NOT ADD WHITESPACES AFTER \ in rsync lines                   #
    # It breaks the command and destroys data                         #
    # You should not modify this, unless you are really REALLY sure   #
    ###################################################################

    # Create a temp file for excludes and includes
    includes_file="$(mktemp --tmpdir "${PROGNAME}.includes.XXXXXX")"
    excludes_file="$(mktemp --tmpdir "${PROGNAME}.excludes.XXXXXX")"
    # … and add them to the list of files to delete at exit
    temp_files="${includes_file} ${excludes_file}"
    trap "rm -f ${temp_files}" EXIT

    # Store includes/excludes in files
    # without blank lines of comments (# or ;)
    echo "${RSYNC_INCLUDES}" | sed -e 's/\s*\(#\|;\).*//; /^\s*$/d' > "${includes_file}"
    echo "${RSYNC_EXCLUDES}" | sed -e 's/\s*\(#\|;\).*//; /^\s*$/d' > "${excludes_file}"

    # Rsync command
    cmd="$(command -v rsync)"

    # Rsync main options
    cmd="${cmd} --archive"
    cmd="${cmd} --itemize-changes"
    cmd="${cmd} --quiet"
    cmd="${cmd} --stats"
    cmd="${cmd} --human-readable"
    cmd="${cmd} --relative"
    cmd="${cmd} --partial"
    cmd="${cmd} --delete"
    cmd="${cmd} --delete-excluded"
    cmd="${cmd} --force"
    cmd="${cmd} --ignore-errors"
    cmd="${cmd} --log-file=${RSYNC_LOGFILE}"
    cmd="${cmd} --rsh='ssh -p ${SSH_PORT} -o \"ConnectTimeout ${SSH_CONNECT_TIMEOUT}\"'"

    # Rsync excludes
    while read line ; do
        cmd="${cmd} --exclude ${line}"
    done < "${excludes_file}"

    # Rsync local sources
    cmd="${cmd} ${default_includes}"
    while read line ; do
        cmd="${cmd} ${line}"
    done < "${includes_file}"

    # Rsync remote destination
    cmd="${cmd} root@${SSH_SERVER}:/var/backup/"

    # output final command
    echo "${cmd}"
}
build_rsync_canary_cmd() {
    # Rsync command
    cmd="$(command -v rsync)"
    # Rsync options
    cmd="${cmd} --rsh='ssh -p ${SSH_PORT} -o \"ConnectTimeout ${SSH_CONNECT_TIMEOUT}\"'"
    # Rsync local source
    cmd="${cmd} ${CANARY_FILE}"
    # Rsync remote destination
    cmd="${cmd} root@${SSH_SERVER}:/var/backup/"

    # output final command
    echo "${cmd}"
}
sync_tasks() {
    n=0
    server=""
    if [ "${SERVERS_FALLBACK}" = "1" ]; then
        # We try to find a suitable server
        while :; do
            server=$(pick_server "${n}")
            test $? = 0 || exit 2

            if test_server "${server}"; then
                break
            else
                server=""
                n=$(( n + 1 ))
            fi
        done
    else
        # we force the server
        server=$(pick_server "${n}")
    fi

    SSH_SERVER=$(echo "${server}" | cut -d':' -f1)
    SSH_PORT=$(echo "${server}" | cut -d':' -f2)

    log "START SYNC_TASKS - server=${server}"

    # default paths, depending on system
    if [ "${SYSTEM}" = "linux" ]; then
        default_includes="/bin /boot /lib /opt /sbin /usr"
    else
        default_includes="/bsd /bin /sbin /usr"
    fi

    # reset Rsync log file
    if [ -n "$(command -v truncate)" ]; then 
        truncate -s 0 "${RSYNC_LOGFILE}"
    else
        printf "" > "${RSYNC_LOGFILE}"
    fi

    # Build the final Rsync command
    rsync_main_cmd=$(build_rsync_main_cmd)

    # … log it
    log "SYNC_TASKS - Rsync main command : ${rsync_main_cmd}"

    # … execute it
    eval "${rsync_main_cmd}"

    rsync_main_rc=$?

    # Copy last lines of rsync log to the main log
    tail -n 30 "${RSYNC_LOGFILE}" >> "${LOGFILE}"

    if [ ${rsync_main_rc} -ne 0 ]; then
        error "rsync returned an error ${rsync_main_rc}, check ${LOGFILE}"
        rc=201
    else
        # Build the canary Rsync command
        rsync_canary_cmd=$(build_rsync_canary_cmd)

        # … log it
        log "SYNC_TASKS - Rsync canary command : ${rsync_canary_cmd}"

        # … execute it
        eval "${rsync_canary_cmd}"
    fi

    log "STOP SYNC_TASKS - server=${server}"
}

# Call test_server with "HOST:PORT" string
# It will return with 0 if the server is reachable.
# It will return with 1 and a message on stderr if not.
test_server() {
    item=$1
    # split HOST and PORT from the input string
    host=$(echo "${item}" | cut -d':' -f1)
    port=$(echo "${item}" | cut -d':' -f2)

    # Test if the server is accepting connections
    ssh -q -o "ConnectTimeout ${SSH_CONNECT_TIMEOUT}" "${host}" -p "${port}" -t "exit"
    # shellcheck disable=SC2181
    if [ $? = 0 ]; then
        # SSH connection is OK
        return 0
    else
        # SSH connection failed
        new_error=$(printf "Failed to connect to \`%s' within %s seconds" "${item}" "${SSH_CONNECT_TIMEOUT}")
        log "${new_error}"
        SERVERS_SSH_ERRORS=$(printf "%s\\n%s" "${SERVERS_SSH_ERRORS}" "${new_error}" | sed -e '/^$/d')

        return 1
    fi
}
# Call pick_server with an optional positive integer to get the nth server in the list.
pick_server() {
    increment=${1:-0}
    list_length=$(echo "${SERVERS}" | wc -w)

    if [ "${increment}" -ge "${list_length}" ]; then
        # We've reached the end of the list
        new_error="No more server available"
        log "${new_error}"
        SERVERS_SSH_ERRORS=$(printf "%s\\n%s" "${SERVERS_SSH_ERRORS}" "${new_error}" | sed -e '/^$/d')

        # Log errors to stderr
        printf "%s\\n" "${SERVERS_SSH_ERRORS}" >&2
        return 1
    fi

    # Extract the day of month, without leading 0 (which would give an octal based number)
    today=$(/bin/date +%e)
    # A salt is useful to randomize the starting point in the list
    # but stay identical each time it's called for a server (based on hostname).
    salt=$(hostname | cksum | cut -d' ' -f1)
    # Pick an integer between 0 and the length of the SERVERS list
    # It changes each day
    item=$(( (today + salt + increment) % list_length ))
    # cut starts counting fields at 1, not 0.
    field=$(( item + 1 ))

    echo "${SERVERS}" | cut -d' ' -f${field}
}
log() {
    msg="${1:-$(cat /dev/stdin)}"
    pid=$$
    printf "[%s] %s[%s]: %s\\n" \
        "$(/bin/date +"${DATE_FORMAT}")" "${PROGNAME}" "${pid}" "${msg}" \
        >> "${LOGFILE}"
}
error() {
    msg="${1:-$(cat /dev/stdin)}"
    pid=$$
    printf "[%s] %s[%s]: %s\\n" \
        "$(/bin/date +"${DATE_FORMAT}")" "${PROGNAME}" "${pid}" "${msg}" \
        >&2
}

main() {
    START_EPOCH=$(/bin/date +%s)
    log "START GLOBAL - VERSION=${VERSION} LOCAL_TASKS=${LOCAL_TASKS} SYNC_TASKS=${SYNC_TASKS}"

    # shellcheck disable=SC2174
    mkdir -p -m 700 ${LOCAL_BACKUP_DIR}

    ## Force umask
    umask 077

    ## Initialize variable to store SSH connection errors
    SERVERS_SSH_ERRORS=""

    ## Verify other evobackup process and kill if needed
    if [ -e "${PIDFILE}" ]; then
        pid=$(cat "${PIDFILE}")
        # Does process still exist ?
        if kill -0 "${pid}" 2> /dev/null; then
            # Killing the childs of evobackup.
            for ppid in $(pgrep -P "${pid}"); do
                kill -9 "${ppid}";
            done
            # Then kill the main PID.
            kill -9 "${pid}"
            printf "%s is still running (PID %s). Process has been killed" "$0" "${pid}\\n" >&2
        else
            rm -f "${PIDFILE}"
        fi
    fi
    echo "$$" > "${PIDFILE}"

    # Initialize a list of files to delete at exit
    # Any file added to the list will also be deleted at exit
    temp_files="${PIDFILE}"

    # shellcheck disable=SC2064
    trap "rm -f ${temp_files}" EXIT

    # Update canary to keep track of each run
    update-evobackup-canary --who "${PROGNAME}"

    if [ "${LOCAL_TASKS}" = "1" ]; then
        local_tasks
    fi

    if [ "${SYNC_TASKS}" = "1" ]; then
        sync_tasks
    fi

    STOP_EPOCH=$(/bin/date +%s)

    if [ "${SYSTEM}" = "openbsd" ]; then
        start_time=$(/bin/date -f "%s" -j "${START_EPOCH}" +"${DATE_FORMAT}")
        stop_time=$(/bin/date -f "%s" -j "${STOP_EPOCH}" +"${DATE_FORMAT}")
    else
        start_time=$(/bin/date --date="@${START_EPOCH}" +"${DATE_FORMAT}")
        stop_time=$(/bin/date --date="@${STOP_EPOCH}" +"${DATE_FORMAT}")
    fi
    duration=$(( STOP_EPOCH - START_EPOCH ))

    log "STOP GLOBAL - start='${start_time}' stop='${stop_time}' duration=${duration}s"

    tail -20 "${LOGFILE}" | mail -s "[info] EvoBackup - Client ${HOSTNAME}" ${MAIL}
}

# set all programs to C language (english)
export LC_ALL=C

# Error on unassigned variable
set -u

# Default return-code (0 == succes)
rc=0

# execute main funciton
main

exit ${rc}