Actually wait let's reorder those args

Hopefully really this time

Dockerfile

@@ -1,24 +1,48 @@
+# Args
+ARG MINECRAFT_VERSION="1.16.5"
+ARG FORGE_VERSION="36.2.26"
+ARG JRE_VERSION="openjdk8-jre"
+
+ARG UID=1520
+ARG USER=minecraft
+ARG GID=1520
+ARG GROUP=minecraft
+
 # The first stage just builds up the modpack
 FROM alpine:latest AS build
 
-# Args
+# Use all of our arguments
-ARG MINECRAFT_VERSION="1.16.5"
+ARG MINECRAFT_VERSION
-ARG FORGE_VERSION="36.2.22"
+ARG FORGE_VERSION
+ARG JRE_VERSION
 
-# The actual setup work
+# Build us up the basics of the Minecraft server environment
 COPY start-server.sh /minecraft/start-server.sh
 WORKDIR /minecraft
-RUN apk add curl openjdk11-jre &&\
+RUN apk add curl "${JRE_VERSION}" &&\
 	curl -L "https://files.minecraftforge.net/maven/net/minecraftforge/forge/${MINECRAFT_VERSION}-${FORGE_VERSION}/forge-${MINECRAFT_VERSION}-${FORGE_VERSION}-installer.jar" -o installer.jar &&\
 	java -jar installer.jar --installServer &&\
 	echo "eula=true" > eula.txt &&\
 	rm installer.jar installer.jar.log && \
 	ln -s "forge-${MINECRAFT_VERSION}-${FORGE_VERSION}.jar" server.jar
 
-# The second stage is the actual container
+# Stuff them in a smaller container with fewer layers
-FROM openjdk:11
+FROM alpine:latest AS final
-RUN apt-get update && apt-get install rsync screen -y
+
+# Use only a subset of arguments
+ARG JRE_VERSION
+ARG UID
+ARG USER
+ARG GID
+ARG GROUP
+
+# Build the thing up
+RUN apk add bash curl findutils rsync screen "${JRE_VERSION}"
 WORKDIR /minecraft
 COPY --from=build /minecraft .
+RUN addgroup -g "${GID}" "${GROUP}" && \
+	adduser -h /minecraft -s /bin/sh -D -H -u "${UID}" -G "${GROUP}" "${USER}" && \
+	chown "${USER}:${GROUP}" /minecraft
+USER $USER
 CMD [ "bash", "start-server.sh" ]
 EXPOSE 25565

LICENSE

@@ -0,0 +1,7 @@
+Copyright 2021 Salt
+
+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.

README.md

@@ -7,12 +7,22 @@ A Dockerfile and some assorted scripts to build a Minecraft Forge server contain
 Deploy as expected:
 
 ```bash
-docker run -p 25565:25565 rehashedsalt/minecraft-forge:1.16.5-36.1.4-1.0.0
+docker run -p 25565:25565 rehashedsalt/minecraft-forge:1.16.5-36.2.35-openjdk11-jre-master
 ```
 
 And badda bing, badda boom, you'll have a Minecraft Forge server of whatever the tag is.
 
-The "latest" tag of each version of Minecraft is somewhere along the lines of "1.16.5-36.1.14-master". See Dockerhub for more info.
+The tag looks long and unweildy, but it's just this:
+
+```
+rehashedsalt/minecraft-forge:${MINECRAFT_VERSION}-${FORGE_VERSION}-${OPENJDK_VERSION}-${BRANCH_OR_TAG_NAME}
+```
+
+You can see what the supported combinations of tags are by looking them up in `build.sh`. Each version only supports one edition of Java and one edition of Forge. Getting CI/CD to automagically determine the latest version of Forge is on the to-do list.
+
+Admittedly, I don't use tags very often. You'd do well to target `master` as the refname if you want bleeding edge stuff.
+
+Full list of tags is available on [Dockerhub](https://hub.docker.com/r/rehashedsalt/minecraft-forge/tags).
 
 ## Server Console
 
@@ -48,6 +58,8 @@ The following arguments may be useful to pass through `$ARGS` from time to time:
 
 * `-Dfml.queryResult=confirm` - Useful when confirming through world corruption
 
+* Consider [this advice from a Forge dev](https://old.reddit.com/r/feedthebeast/comments/5jhuk9/modded_mc_and_memory_usage_a_history_with_a/) (circa 5+ years ago but still pretty relevant)
+
 ## Weird Defaults
 
 The default `server.properties` contains the following changes to better facilitate usage in a modded environment:

build.sh

@@ -2,29 +2,52 @@
 #
 # Build the Docker image for a series of different Forge versions
 #
+set -e
 
 # MC version list
-declare -a mcversions=(
+readonly -a mcversions=(
+	"1.12.2"
 	"1.16.5"
+	"1.18.2"
 )
 
 # Forge version dictionary (we only support one version per)
-declare -A forgeversions=(
+readonly -A forgeversions=(
-	["1.16.5"]="36.2.22"
+	["1.12.2"]="14.23.5.2855"
+	["1.16.5"]="36.2.35"
+	["1.18.2"]="40.1.20"
+)
+
+# JRE versions (in the form of Alpine packages)
+readonly -A jreversions=(
+	["1.12.2"]="openjdk8-jre"
+	["1.16.5"]="openjdk11-jre"
+	["1.18.2"]="openjdk11-jre"
 )
 
 # Build images
 docker buildx create --use
 for mc in ${mcversions[@]}; do
 	forge="${forgeversions[$mc]}"
-	echo "Building image for Minecraft $mc, Forge $forge, CI_COMMIT_REF_NAME of $CI_COMMIT_REF_NAME"
+	jre="${jreversions[$mc]}"
+	CI_HUB_USERNAME="${CI_HUB_USERNAME:=rehashedsalt}"
+	CI_PROJECT_NAME="${CI_PROJECT_NAME:=minecraft-forge}"
+	tag="$CI_HUB_USERNAME/$CI_PROJECT_NAME:$mc-${CI_COMMIT_REF_NAME:=bleeding}"
+	echo "Building image..."
+	echo "    Minecraft:   $mc"
+	echo "    Forge:       $forge"
+	echo "    JRE:         $jre"
+	echo "    Ref:         $CI_COMMIT_REF_NAME"
+	echo "Dockerhub tag:   $tag"
 	# --no-cache is required for clean builds
 	docker buildx build \
 		--build-arg MINECRAFT_VERSION="$mc" \
 		--build-arg FORGE_VERSION="$forge" \
+		--build-arg JRE_VERSION="$jre" \
 		--no-cache \
 		--platform linux/amd64 \
-		--tag "$CI_HUB_USERNAME/$CI_PROJECT_NAME:$mc-$forge-${CI_COMMIT_REF_NAME:=bleeding}" \
+		--progress plain \
+		--tag "$tag" \
 		--push \
 		.
 done

start-server.sh

@@ -13,10 +13,16 @@ if [ -n "$FORGE_PACK_ZIP" ]; then
 	tmpdir="$(mktemp -d)"
 	pushd "$tmpdir" > /dev/null 2>&1
 	curl -L "$FORGE_PACK_ZIP" -o pack.zip
-	unzip pack.zip
+	unzip -q pack.zip
+	ls -alh
 	directory="$(find . -type d -iname "mods" -execdir pwd \; | sort -n | head -n 1)"
+	if [ -z "$directory" ]; then
+		echo "Unable to find mods directory"
+	else
 		echo "Found modpack directory: $directory"
-	rsync -av --ignore-existing "$directory"/ /minecraft/
+	fi
+	echo "Syncing content to /minecraft"
+	rsync --no-perms --no-owner --no-group --ignore-existing "$directory"/ /minecraft/
 	popd > /dev/null 2>&1
 fi