#!/bin/sh -e
# Backup script to be run from pre_update_hook
# Written by Markus Armbruster, 2005-2012
# This script is in the public domain.

# Use: edit configuration variables below to taste, then set
#   pre_update_hook = /wherever/backup
# in econfig.

# Rules when running as pre_update_hook:
# Data directory is working directory.
# stdin, stdout, stderr are redirected to /dev/null
# Exit code other than zero cancels update!
#
# This script is as simple as possible, since failure cancels the
# update.

# Configuration

# How to name backups
#
# If you back up multiple games to the same directories, better change
# this to include a unique game name.
#
# Single name, keep just the last backup:
name=data
# Name with timestamp, keep all backups:
#name=data-`date +%Y-%m-%d-%H:%M`

# Where to store the backups on the local machine
#
# Storing backups on the same machine is stupid, and on the same file
# system is criminally stupid, so you better change this, unless you
# copy them to another machine.
local_dir=../backup

# Copy backups to remote machine using SSH
#
# Don't copy (are you *sure* you want to be stupid?):
remote_host=
remote_dir=
email=
#
# Do copy:
#remote_host=user@host
#remote_dir=empire/backup
#email=user@host

# End of configuration

# Create local backup directory if necessary
mkdir -p $local_dir

# Tar up the data directory
arc=$local_dir/$name.tar.gz
tar czf $arc .

# Copy the backup to another machine with SSH, in the background
#
# The obvious method requires a key that is not protected by a
# passphrase.  Trusting such keys remotely is usually a bad idea, but
# it might be tolerable if a special user runs the server, and that
# user's privileges are carefully limited.
if [ "$remote_host" ]
then
    nohup sh -c "scp -qBp '$arc' '$remote_host:$remote_dir' 2>&1 | mailx -s 'Empire backup save failed' '$email'" </dev/null >/dev/null 2>&1 &
fi
#
# A more secure alternative is to replace the scp command by something like
#    ssh -q -T -o BatchMode=yes -o IdentitiesOnly=yes -i "$HOME/.ssh/empire_id_rsa" $remote_host <"$arc"
# where $HOME/.ssh/empire_id_rsa contains a private key specifically
# created for Empire backup, without a passphrase, and authorized_keys
# on $remote_host contains the matching public key prepended by
#   command="cat >empire/backup/data-`/bin/date +%Y-%m-%d-%H:%M`.tar.gz",no-pty,no-port-forwarding