Space Engineers setup.sh

#! /bin/sh

# Configure an Ubuntu system for running Space Engineers. Flagrantly untested.
# Seriously, I haven't even run this once.

# TODO: Report progress to the web UI.
# TODO: Error checking/early failure.

# User data should contain:
#
#   AWS_ACCESS_KEY_ID:     The access key ID,
#   AWS_SECRET_ACCESS_KEY: secret,
#   AWS_REGION:            and AWS region for configuration of the AWS CLI.
#   GAME_EBS_VOLUME:       The EBS volume which stores the game data.
eval $(ec2metadata --user-data)

if [ -z "$AWS_ACCESS_KEY_ID" ] \
        || [ -z "$AWS_SECRET_ACCESS_KEY" ] \
        || [ -z "$AWS_REGION" ] \
        || [ -z "$GAME_EBS_VOLUME" ]
then
    echo "$0: missing configuration in user data!" 1>&2
    exit 1
fi

# The maximum amount of time for which the game can be idle (no logged-in
# players) before shutting down the server.
MAX_GAME_IDLE=$(expr 15 \* 60) # seconds
# How frequently to check the number of logged-in players, and whether or not
# our instance is about to be interrupted.
CHECK_INTERVAL=5 # seconds

# The Linux distribution we're running on...
DISTRO="$(lsb_release --id | cut -d ':' -f 2 | tr -d '[:space:]' | tr '[:upper:]' '[:lower:]')"
# ...and the codename of the release version.
RELEASE="$(lsb_release --codename | cut -d ':' -f 2 | tr -d '[:space:]' | tr '[:upper:]' '[:lower:]')"
# These are used to ensure we pull in the appropriate build of Wine.

# Tell APT where to get the newest upstream Wine build.
dpkg --add-architecture i386
wget -nc https://dl.winehq.org/wine-builds/winehq.key
apt-key add winehq.key
apt-add-repository "deb https://dl.winehq.org/wine-builds/$DISTRO/ $RELEASE main"
if [ "$DISTRO" == "ubuntu" ] && [ "$RELEASE" == "bionic" ]
then
    # Required for `libfaudio0`.
    add-apt-repository ppa:cybermax-dexter/sdl2-backport
fi

# Get the system up to date.
apt update
apt upgrade -y
# Steam prompts for license acceptance.
cat <<ACCEPT | debconf-set-selections
steam steam/license note ""
steam steam/question select "I AGREE"
ACCEPT
# xvfb/x11vnc aren't typically necessary, but are nice to have around in case
# you need to run winecfg.
apt install -y awscli \
               steamcmd \
               winehq-stable \
               winetricks \
               xvfb \
               x11vnc

# Create a user to run the game. We need to match the UID/GID which match
# the contents of the data EBS volume attached below.
groupadd --gid 1001 spaceengineers
useradd --uid 1001 \
        --gid 1001 \
        --home-dir /home/spaceengineers \
        --create-home \
        --shell /bin/bash \
        spaceengineers

# TODO: How do we securely get these environment variables into the instance?
# `ec2metadata --user-data`? https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-metadata.html
# specifically warns against using this mechanism for key injection.
# Another option would be to attach the volume via the AWS CLI from outside
# the EC2 instance. Then have this script sit at the while-loop waiting for the
# block device to show up.
aws configure set aws_access_key_id "$AWS_ACCESS_KEY_ID"
aws configure set aws_secret_access_key "$AWS_SECRET_ACCESS_KEY"
aws configure set region "$AWS_REGION"

# Game data (the game user's home directory) is stored in its own EBS volume.
# The last argument is supposed to be the attachment point, but this seems to
# be ignored. Not sure if this is because the EC2 instance type I was testing
# with pretends that EBS volumes are NVMe, or if this would happen everywhere.
# The attachment indicated by `aws ec2 describe-volumes --volume-id ...`
# incorrectly reports the same attachment point as asked for in the
# `attach-volume` invocation, so that's not helpful for determining the real
# attachment point.
aws ec2 attach-volume --instance-id $(ec2metadata --instance-id) \
                      --volume-id "$GAME_EBS_VOLUME" \
                      --device /dev/xvdf
while ! [ -e /dev/nvme1n1 ]
then
    sleep 1
fi
# TODO: Diff the output of lsblk before/after running the `attach-volume` to
# confirm the EC2 volume attachment point.
mount /dev/nvme1n1 /home/spaceengineers

# Log in as the game user.
su spaceengineers

# Update Space Engineers.
# force_install_dir needs to be an absolute path; the shell will expand ~.
steamcmd +login anonymous \
         +force_install_dir ~/spaceengineers \
         +app_update 298740 validate \
         +quit

# Launch Space Engineers. This assumes `wine64 winecfg` has already been used
# to seed a 64-bit Wine prefix, and `winetricks dotnet461` has been installed.
cd ~/spaceengineers/DedicatedServer64
wine64 SpaceEngineersDedicated.exe -console &
se_pid=$!

# TODO: Confirm successful game start.
sleep 60

# Switch login back to `ubuntu`.
exit

# Wait until we need to shut down.
last_game_activity=$(date +%s)
while true
do
    # TODO: Poll VRAGE remote management API.
    if true
    then
        last_game_activity=$(date +%s)
    fi

    # Has the game been idle for long enough to warrant termination?
    now=$(date +%s)
    if [ $(expr $now - $last_game_activity) -gt $MAX_GAME_IDLE ]
    then
        break
    fi

    # Does EC2 want to interrupt us?
    if [ "$(ec2metadata --instance-action)" != "none" ]
    then
        break
    fi

    sleep $CHECK_INTERVAL
done

# Wait for the SE server to terminate.
kill $se_pid
while kill -0 $se_pid
do
    sleep 1
done

# Shutdown should cleanly shut down everything and unmount the data EBS volume.
systemctl shutdown