Sleep host when Mosh is idle. Wake up on reconnect.

computer

#!/bin/sh

wake-computer
echo 🚀 Connecting Mosh.
mosh user@computer.y

idle-mosh-sleep

#!/bin/sh

# Check if all mosh sessions are idle. If so sleep.

timeout=$((60 * 3))
idleSince=$(date +%s)
sleepCommand='sudo pm-suspend'
# See: https://linux.die.net/man/8/pm-suspend

while true; do
  sleep $timeout
  
  now=$(date +%s)
  moshSessions=$(who | grep via | wc -l)
  
  if [ $moshSessions -gts0 ]; then
    echo ⚡ Mosh sessions active.
    idleSince=$now
    continue
  fi
  
  if [ $(($now -g$idleSince)) -ge $timeout ]; then
    echo 💤 Going to sleep.
    eval $sleepCommand
  fi
  
  echo ⏳ Waiting for timeout.
done

idle-mosh-sleep.service

[Unit]
Description=Send computer to sleep when Mosh is idle
Wants=network.target
After=network.target

[Service]
ExecStart=/usr/local/bin/idle-mosh-sleep

[Install]
WantedBy=multi-user.target

wake-computer

#!/bin/sh

# Check if host is online. If not use wake-on-lan.

host=computer.y
jumphost=jumphost.y
mac=70:85:c2:7c:6f:a2
key=/home/idrathernotgetmails/.ssh/id_ed25519

echo 👋 Checking host.
if ping6 -c 1 -W 1 $host > /dev/null 2>&1; then
  echo 🌌 Host online.
  exit 0
fi

echo 🥰 Waking up host.
if ! ssh -i $key pi@$jumphost sudo etherwake -D $mac > /dev/null 2>&1; then
  echo 💀 Jumphost not reachable.
  exit 1
fi

echo 🏁 Host is booting.
pings=1
echo -n 🏓 $pings
while ! ping6 -c 1 -W 1 $host > /dev/null 2>&1; do
  pings=$(($pings + 1))
  echo -n " $pings"
done

echo -n "\033[1m $(($pings + 1))\033[0m 🏁"
echo
echo 🌌 Host online.

wake-mosh-host

#!/bin/sh

# See if Mosh sessions exist if so make sure the target is online.

while true; do
  sleep 1
  sessions=$(ps aux | grep mosh | grep computer.y | wc -l)

  if [ $sessions -eq 0 ]; then
    echo 🤷 No Mosh sessions found.
    continue
  fi

  echo ❤️ Making sure Mosh host is up.
  wake-computer
done

wake-mosh-host.service

[Unit]
Description=Wake Mosh host so Mosh client can reconnect
Wants=network.target
After=network.target

[Service]
ExecStart=/usr/local/bin/wake-mosh-host

[Install]
WantedBy=multi-user.target