Server sleep scripts. Run in the evening as a cron job.

try-to-sleep

#! /bin/bash

#
# Save as /usr/local/sbin/try-to-sleep
#
# Have cron try it regularly.
# /etc/cron.d/try-to-sleep:
# 12,27,42,57 22-23,0-5 * * * root /usr/local/sbin/try-to-sleep
#

set -o errexit
set -o noclobber
set -o nounset
set -o pipefail

STAY_AWAKE="/var/local/stay-awake"
IGNORED_CRONJOBS='^(/usr/sbin/cron|/usr/sbin/incrond|/usr/bin/atop|.* /usr/local/sbin/try-to-sleep)'
RECENT_MINUTES=15

_may_sleep=1
_log=''

_dry_run=''
_verbose=''
_debug=''


usage() {
  echo "Usage: $0 [ --dry-run | -n ] [ --verbose | -v ] [ --debug | -d ]"
}

while (( $# > 0 )); do
  case "$1" in
    --dry-run|-n)
      shift
      _dry_run=1
      ;;
    --verbose|-v)
      shift
      _verbose=1
      ;;
    --debug|-d)
      shift
      _debug=1
      ;;
    --help|-h)
      usage
      exit 0
      ;;
    *)
      usage
      exit 1
      ;;
  esac
done


doit=''
if [[ $_dry_run = 1 ]]; then
  doit=echo
fi

can_sleep() {
  [[ $_may_sleep = 1 ]]
}

dont_sleep() {
  _may_sleep=0
}

continue_checks() {
  [[ $_may_sleep = 1 ]] || [[ $_verbose = 1 ]]
}


active_connections() {
  netstat -tn | fgrep 'ESTABLISHED' || [[ $? = 1 ]]
}

running_cronjobs() {
  local pids
  pids=$( cat /sys/fs/cgroup/systemd/system.slice/*cron.service/cgroup.procs )
  if [[ -n $pids ]]; then
    ps -ho command -p $pids \
    | grep -Eiv "$IGNORED_CRONJOBS" || [[ $? = 1 ]]
  fi
}

no_rest_for_the_wicked() {
  test -f "$STAY_AWAKE"
}

log() {
  if [[ $_verbose = 1 ]]; then
    _log="${_log}${*}\n"
  fi
}

debug() {
  if [[ $_debug = 1 ]]; then
    echo "$*"
  fi
}

dont_sleep_if() {
  if continue_checks; then
    debug "dont_sleep_if $1"
    if $1; then
      debug "-> DON'T"
      log "$2"
      dont_sleep
    else
      debug "-> MAY"
    fi
  fi
}

dont_sleep_if_any() {
  if continue_checks; then
    debug "dont_sleep_if_any $1"
    local out
    out=$( $1 )
    debug "$out"
    if [[ -n $out ]]; then
      debug "-> DON'T"
      log "$2"
      dont_sleep
    else
      debug "-> MAY"
    fi
  fi
}

dont_sleep_if_running() {
  if continue_checks; then
    debug "dont_sleep_if_running $1"
    local p msg
    p="$1"
    if pidof "$p" > /dev/null ; then
      debug "-> DON'T"
      msg=${2:-"Process is running: $p"}
      log "$msg"
      dont_sleep
    else
      debug "-> MAY"
    fi
  fi
}

dont_sleep_if_recent() {
  if continue_checks; then
    debug "dont_sleep_if_recent $1"
    local file now age msg
    file="$1"
    now=$( date +'%s' )
    age=$( stat -c '%Y' "$file" )
    if (( (now - age) <= ($RECENT_MINUTES * 60) )); then
      debug "-> DON'T"
      msg=${2:-"Recently modified: $file"}
      log "$msg"
      dont_sleep
    else
      debug "-> MAY"
    fi
  fi
}


dont_sleep_if           no_rest_for_the_wicked  "Staying awake as requested"
dont_sleep_if_any       running_cronjobs        "Cron jobs are running"
dont_sleep_if_any       active_connections      "Connections are open"

dont_sleep_if_running   sftp-server
dont_sleep_if_running   btrfs
dont_sleep_if_running   btrfsck
dont_sleep_if_running   fstrim
dont_sleep_if_running   rsync
dont_sleep_if_running   snapperd
dont_sleep_if_running   tmux

dont_sleep_if_recent    /var/lib/mpd/state

echo -en "$_log"

if can_sleep; then
  $doit systemctl hybrid-sleep
elif [[ $_verbose = 1 ]]; then
  echo "Can't go to sleep yet."
fi

exit 0