autoreject.sh

#!/bin/sh

# The MIT License (MIT)
# Copyright (c) 2016 Chris Olstrom <[email protected]>

# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

WORKDIR=${WORKDIR:-"${PWD}"}
LOGS=${LOGS:-"${WORKDIR}/logs"}
FML_SERVER_LOG=${LOGS}/${FML_SERVER_LOG:-'fml-server-latest.log'}
MOD_LIST=${WORKDIR}/${MOD_LIST:-'autoreject.modlist'}

fml_server_log_exists() {
    test -f "${FML_SERVER_LOG}"
}

suggest_client_only_mods() {
    if fml_server_log_exists
    then
	cat >&2 <<EOF
According to ${FML_SERVER_LOG}, the following are client-only mods and
can be safely disabled:

EOF
	awk '/client side only/ { print $7 }' "${FML_SERVER_LOG}"

	cat >&2 <<EOF

If this list looks satisfactory, you can write it to ${MOD_LIST} like so:

${0} >${MOD_LIST} 2>/dev/null

EOF
    else
	cat >&2 <<EOF

Precondition Failed: ${FML_SERVER_LOG} must exist.
====================

What happened?
--------------

Expected ${FML_SERVER_LOG} to be a log file, but found nothing (not
even an empty file).

Why did this happen?
--------------------

- Logs are generated when your server runs. If you haven't launched it
  yet (or if you have deleted or disabled logs), this is why you have
  no logs.

- If you are logging to somewhere other than ${LOGS}, try running:

env LOGS=/path/to/your/logs ${0}

Recommended Action
------------------

Launch the server at least once.

EOF
	return 111
    fi
}

modlist_exists() {
    test -f "${MOD_LIST}"
}

remove_mods() {
    if modlist_exists
    then
	cat ${MOD_LIST} | while read -r MOD
	do
	    rm -vf mods/${MOD}-*.jar
	done
    else
	cat >&2 <<EOF

Precondition Check Failed: ${MOD_LIST} must exist
=========================

What happened?
--------------

Expected to find a list of (zero or more) mods to remove at
${MOD_LIST}, but found nothing (not even an empty file).

Why did this happen?
--------------------

- You may need to create this file, if you haven't already.

- If your list of mods to remove is somewhere other than ${MOD_LIST},
  try running:

env MOD_LIST=path/to/your/mod.list ${0}

Recommended Action
------------------

- Create an empty file at ${MOD_LIST} if you have no mods you want to
  remove.

- Place a list of mods to remove at ${MOD_LIST}. This should be a
  file containing one mod to remove per line.

EOF
	return 111
    fi
}

main() {
    remove_mods || suggest_client_only_mods
}

main

What is it?

A maintenance script for modded Minecraft servers. It reads a list of mods to remove from a file, and removes them.

When would I want this?

• When updating modpacks, this provides a repeatable process for removing mods from a pack, without relying on human memory.
• It can trivially be invoked from an update script or deployment system.
• It is configured entirely through environment, making it more usable in containerized deployments, or continuous integration systems (a pipeline that consumes a base modpack and produces a modified pack, for instance).

Notable Features

• It can parse Minecraft server logs and generate a list of client-only mods suitable for removal (a common server-side change).