self-hosting/minecraft/forge/Dockerfile

FROM openjdk:8-jre-slim

# Build arguments
ARG MC_VERSION
ARG FORGE_VERSION

# Install mcstatus for healthchecks
RUN apt update && \
    apt install --no-install-recommends -y python3-minimal python3-setuptools python3-pip && \
    python3 -m pip install mcstatus && \
    apt --purge remove -y python3-pip python3-setuptools && \
    apt clean

# Create worlds and config directory
WORKDIR /app
RUN mkdir worlds config

# Download installer jar
ADD "https://files.minecraftforge.net/maven/net/minecraftforge/forge/${MC_VERSION}-${FORGE_VERSION}/forge-${MC_VERSION}-${FORGE_VERSION}-installer.jar" installer.jar

# Install forge & remove installer
RUN java -jar installer.jar server --installServer && \
    rm installer.jar installer.jar.log

# Store the cache in an anonymous volume, which means it won't get stored in the other volumes
VOLUME /mc/config/cache

WORKDIR /mc/config

# Default value to keep users from eating up all ram accidentally
ENV XMX=4
ENV MC_VERSION="${MC_VERSION}"
ENV FORGE_VERSION="${FORGE_VERSION}"
# Forge doesn't use one single name, so this is needed to know the name of the executable
ENV FORGE_JAR="forge-${MC_VERSION}-${FORGE_VERSION}.jar"

# Entrypoint runs in /app/config
COPY entrypoint.sh /entrypoint.sh
WORKDIR /app/config
ENTRYPOINT /entrypoint.sh

HEALTHCHECK --interval=30s --timeout=5s --start-period=15s --retries=3 \
    CMD mcstatus localhost:25565 ping