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[libremanage.git] / relay-cmd

#!/bin/bash

trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" returned $?" >&2' ERR

usage() {
  cat <<EOF
Usage: relay-cmd poweroff|poweron|reboot HOSTNAME|CHANNEL [RELAY_ID]

RELAY_ID is not needed if only 1 relay device is connected.  To
understand CHANNEL and RELAY_ID, run hidusb-relay-cmd and
hidusb-relay-cmd state.  I recommend writing a config in
/etc/relay-cmd.conf , then using HOSTNAME instead of CHANNEL and
RELAY_ID. It serves as documentation of what you connected the relay
to. Example config:

# This config is just sourced from bash, so make sure its valid bash.
# relay_id is not needed if only 1 relay is connected.
cephserver3_channel=1
cephserver3_relay_id=HURTM
cephserver2_channel=2
cephserver2_relay_id=HURTM
EOF
  exit $1
}


if (( $# < 2 )); then
  usage
fi

read action chan relay_id  <<<"$@"

if [[ -e /etc/relay-cmd.conf ]]; then
  source /etc/relay-cmd.conf
fi

# we know HOSTNAME is given if it doesn't start with a number.
if [[ $chan != [0-9]* ]]; then
  chan_var=${chan}_channel
  chan=${!chan_var}
  if [[ ! $chan ]]; then
    echo "error: channel not found in /etc/relay-cmd.conf" >&2
    exit 1
  fi
  if [[ ! $relay_id ]]; then
    relay_id_var=${chan}_relay_id
    relay=${!relay_id_var}
  fi
fi


if hidusb-relay-cmd state | grep ON; then
  printf "%s\n" "WARNING: output from hidusb-relay-cmd state shows an ON relay. this could mean another command instance is running, or it got stuck on due to an uncompleted command." >&2
fi


case $(hidusb-relay-cmd state|wc -l) in
  0)
    echo "error: got 0 lines from running hidusb-relay-cmd state" >&2
    exit 1
    ;;
  1) : ;;
  *)
    if [[ ! $relay_id ]]; then
      echo "error: more than 1 relay device, so passing its id is required" >&2
      exit 1
    fi
    ;;
esac


if [[ $relay_id ]]; then
  # leave this as an empty var if its not passed
  relay_id_arg="id=$relay_id"
fi

# verbose command
v() {
  printf "+ %s\n" "$*"
  "$@"
}


# ignore hup so we complete even if there is a connection problem.
trap '' HUP
echo "$0: doing $action. shell commands are printed to the terminal:"
case $action in
  poweroff)
    v hidusb-relay-cmd $relay_id_arg on $chan
    v sleep 6
    v hidusb-relay-cmd $relay_id_arg off $chan
    ;;
  poweron)
    v hidusb-relay-cmd $relay_id_arg on $chan
    v sleep 1
    v hidusb-relay-cmd $relay_id_arg off $chan
    ;;
  reboot)
    v hidusb-relay-cmd $relay_id_arg on $chan
    v sleep 6
    v hidusb-relay-cmd $relay_id_arg off $chan
    v sleep 1
    v hidusb-relay-cmd $relay_id_arg on $chan
    v sleep 1
    v hidusb-relay-cmd $relay_id_arg off $chan
    ;;
  *)
    echo "error: action arg not supported" >&2
    exit 1
esac
echo "$0: script ended. exiting"