feat: ✨ Add memory limit calculations & server setup/updates

.dockerignore

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+.gitignore
+.dockerignore
+Dockerfile
+LICENSE
+README.md
+.vscode
+.git
+.history/
+*.vsix

Dockerfile

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+FROM eclipse-temurin:22-alpine
+
+COPY --from=golang:1.22-alpine /usr/local/go/ /usr/local/go/
+ENV PATH="/root/go/bin:/usr/local/go/bin:${PATH}"
+
+RUN go install github.com/nothub/mrpack-install@v0.16.10
+
+VOLUME /server
+
+COPY entrypoint.sh /entrypoint.sh
+
+ENTRYPOINT [ "/entrypoint.sh" ]

entrypoint.sh

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+#!/bin/sh
+
+MEMSIZE=$(grep MemTotal /proc/meminfo | awk '{print $2 * 1024}')
+MEMLIMIT=$(cat /sys/fs/cgroup/memory/memory.limit_in_bytes)
+MEMLIMIT=$((MEMLIMIT<MEMSIZE ? MEMLIMIT : MEMSIZE))
+MEMOFFSET=1073741824
+SERVER_MEM=$((MEMLIMIT-MEMOFFSET))
+
+if [ -e "/server/modpack.json" ]; then
+    mrpack-install --server-dir /server --server-file server.jar update "$@" <<EOF
+y
+EOF
+else
+    mrpack-install --server-dir /server --server-file server.jar "$@"
+fi
+
+cd /server
+echo "eula=true" > /server/eula.txt
+cat eula.txt
+java -Xms$SERVER_MEM -Xmx$SERVER_MEM -XX:+UseG1GC \
+     -XX:+ParallelRefProcEnabled -XX:MaxGCPauseMillis=200 \
+     -XX:+UnlockExperimentalVMOptions -XX:+DisableExplicitGC \
+     -XX:+AlwaysPreTouch -XX:G1NewSizePercent=30 \
+     -XX:G1MaxNewSizePercent=40 -XX:G1HeapRegionSize=8M \
+     -XX:G1ReservePercent=20 -XX:G1HeapWastePercent=5 \
+     -XX:G1MixedGCCountTarget=4 -XX:InitiatingHeapOccupancyPercent=15 \
+     -XX:G1MixedGCLiveThresholdPercent=90 -XX:G1RSetUpdatingPauseTimePercent=5 \
+     -XX:SurvivorRatio=32 -XX:+PerfDisableSharedMem -XX:MaxTenuringThreshold=1 \
+     -Dusing.aikars.flags=https://mcflags.emc.gs -Daikars.new.flags=true \
+     -jar server.jar