Add project files

.github/workflows/main.yml

@@ -0,0 +1,25 @@
+name: Build Native Minecraft Server
+on: [ push, pull_request ]
+jobs:
+  build:
+    name: Build on ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+    steps:
+      - uses: actions/checkout@v2
+      - uses: graalvm/setup-graalvm@v1
+        with:
+          version: '22.2.0'
+          java-version: '17'
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+      - name: Check build.sh
+        shell: bash
+        run: shellcheck build.sh
+        if: ${{ matrix.os == 'ubuntu-latest' }}
+      - name: Build and run native Minecraft server
+        shell: bash
+        run: |
+          ./build.sh
+          ./native-minecraft-server --help

.gitignore

@@ -0,0 +1,9 @@
+/*.json
+build
+debug
+eula.txt
+logs
+native-minecraft-server
+server.properties
+sources
+world

README.md

@@ -1 +1,62 @@
-# Native Minecraft Server
+# Native Minecraft Servers with GraalVM Native Image
+
+[![Build Native Minecraft Server](https://github.com/hpi-swa/native-minecraft-server/actions/workflows/main.yml/badge.svg)](https://github.com/hpi-swa/native-minecraft-server/actions/workflows/main.yml)
+
+![Banner](./assets/graalvm_native_image_minecraft_banner.jpg)
+
+The Minecraft server is known to require a lot of CPU and memory resources and can be hard to deploy.
+This project makes it possible to compile the Minecraft server into a self-contained native executable using [GraalVM Native Image][ni].
+As such, it is supposed to require fewer CPU and memory resources, provide better startup times, and be easier and cheaper to deploy.
+
+A native Minecraft server is less than 120MB in size, and with that significantly smaller than Minecraft's `server.jar` plus a JDK required to run it.
+With [upx] compression, the size of the native executable can be reduced even further to less than 40MB, which is smaller than just the `server.jar`.
+Initial experiments also suggest competitive run-time performance with a reduced memory footprint.
+For best results, build with [GraalVM Enterprise][ee] Native Image, which provides better performance and lower memory usage than the Community Edition, and try out the [G1 GC][g1gc] and [Profile-Guided Optimizations][pgo].
+The [Oracle Cloud Free Tier][oci-free] not only provides four Ampere A1 cores and 24 GB of RAM always free, which is plenty for [hosting a Minecraft server][oci-minecraft], but also free access to GraalVM Enterprise.
+
+Check out [this blog post][blog-post] for more information.
+
+*Disclaimer: This project is meant for demonstration purposes only and intended to help the Minecraft community evaluate the use of GraalVM Native Image. Please use at your own risk.*
+
+## Getting Started
+
+1. Download GraalVM [Community][ce] or [Enterprise][ee] *(GraalVM 22.2.0 or later is required)*.  
+*Optional: make sure [upx] is on your `$PATH` to enable compression.*
+2. Download or check out this repository and run the [`build.sh`](build.sh).
+3. Launch the native Minecraft server with `./native-minecraft-server`.  
+*The first time you run the server, you will have to follow the regular procedure of accepting Minecraft's EULA.*
+
+## How It Works
+This project only contains the `build.sh` script and [reachability metadata][metadata] for building a native Minecraft server.
+The `build.sh` script first downloads Minecraft's `server.jar` and extracts jars and other resources from it.
+Afterward, it invokes GraalVM Native Image with an appropriate configuration to generate a native version of the Minecraft server.
+Finally, and only if [upx] is on the `$PATH`, the script will compress the native executable.
+
+## Limitations and Known Issues
+
+- The configuration currently only supports Minecraft `1.18.2`.
+- The server GUI is not yet supported.
+- Mods are currently not supported.
+- There is no build script for Windows yet, but the [WSL] should work.
+- The native executable sometimes fails on startup. Restarting it a few times usually helps.  
+*Error: `com.mojang.datafixers.types.templates.List$ListType cannot be cast to java.lang.Comparable`*. 
+
+## Contributions
+Please [report any issues here on GitHub][issues] and open pull requests if you'd like to contribute to the project.
+
+## License
+This project is released under the [MIT license](./LICENSE).
+
+
+[blog-post]: https://medium.com/p/1a3f6a92eb48
+[ce]: https://github.com/graalvm/graalvm-ce-builds/releases/latest
+[ee]: https://www.oracle.com/downloads/graalvm-downloads.html
+[g1gc]: https://www.graalvm.org/22.2/reference-manual/native-image/optimizations-and-performance/MemoryManagement/
+[issues]: https://github.com/hpi-swa/native-minecraft-server/issues
+[metadata]: https://www.graalvm.org/22.2/reference-manual/native-image/metadata/
+[ni]: https://www.graalvm.org/native-image/
+[oci-free]: https://www.oracle.com/cloud/free/
+[oci-minecraft]: https://blogs.oracle.com/developers/post/how-to-set-up-and-run-a-really-powerful-free-minecraft-server-in-the-cloud
+[pgo]: https://www.graalvm.org/22.2/reference-manual/native-image/guides/optimize-native-executable-with-pgo/
+[upx]: https://upx.github.io/
+[wsl]: https://docs.microsoft.com/en-us/windows/wsl/install

build.sh

@@ -0,0 +1,75 @@
+#!/usr/bin/env bash
+
+set -o errexit
+set -o nounset
+
+SERVER_JAR_DL="https://launcher.mojang.com/v1/objects/c8f83c5655308435b3dcf03c06d9fe8740a77469/server.jar"
+SCRIPT_DIR=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
+BUILD_DIR="${SCRIPT_DIR}/build"
+JAR_PATH="${BUILD_DIR}/server.jar"
+META_INF_PATH="${BUILD_DIR}/META-INF"
+BINARY_NAME="native-minecraft-server"
+NI_EXEC="${GRAALVM_HOME:-}/bin/native-image"
+readonly SERVER_JAR_DL SCRIPT_DIR BUILD_DIR JAR_PATH META_INF_PATH BINARY_NAME NI_EXEC
+
+if [[ -z "${GRAALVM_HOME:-}" ]]; then
+    echo "\$GRAALVM_HOME is not set. Please provide a GraalVM installation. Exiting..."
+    exit 1
+fi
+
+if ! command -v "${NI_EXEC}" &> /dev/null; then
+    echo "Installing GraalVM Native Image..."
+    "${GRAALVM_HOME}/bin/gu" install --no-progress native-image
+fi
+
+if [[ ! -d "${BUILD_DIR}" ]]; then
+    mkdir "${BUILD_DIR}"
+fi
+pushd "${BUILD_DIR}" > /dev/null
+
+if [[ ! -f "${JAR_PATH}" ]]; then
+    echo "Downloading Minecraft's server.jar..."
+    curl --show-error --fail --location -o "${JAR_PATH}" "${SERVER_JAR_DL}"
+fi
+
+if [[ ! -d "${META_INF_PATH}" ]]; then
+    echo "Extracting resources from Minecraft's server.jar..."
+    unzip -qq "${JAR_PATH}" "META-INF/*" -d "."
+fi
+
+if [[ ! -f "${META_INF_PATH}/classpath-joined" ]]; then
+    echo "Unable to determine classpath. Exiting..."
+    exit 1
+fi
+CLASSPATH_JOINED=$(cat "${META_INF_PATH}/classpath-joined")
+readonly CLASSPATH_JOINED
+
+if [[ ! -f "${META_INF_PATH}/main-class" ]]; then
+    echo "Unable to determine main class. Exiting..."
+    exit 1
+fi
+MAIN_CLASS=$(cat "${META_INF_PATH}/main-class")
+readonly MAIN_CLASS
+
+pushd "${META_INF_PATH}" > /dev/null
+"${NI_EXEC}" --no-fallback \
+    -H:ConfigurationFileDirectories="${SCRIPT_DIR}/configuration/" \
+    --enable-url-protocols=https \
+    --initialize-at-run-time=io.netty \
+    -H:+AllowVMInspection \
+    --initialize-at-build-time=net.minecraft.util.profiling.jfr.event \
+    -H:Name="${BINARY_NAME}" \
+    -cp "${CLASSPATH_JOINED//;/:}" \
+    "${MAIN_CLASS}"
+mv "${BINARY_NAME}" "${SCRIPT_DIR}/${BINARY_NAME}"
+popd > /dev/null # Exit $META_INF_PATH
+popd > /dev/null # Exit $BUILD_DIR
+
+if command -v upx &> /dev/null; then
+    echo "Compressing the native Minecraft server with upx..."
+    upx "${SCRIPT_DIR}/${BINARY_NAME}"
+fi
+
+echo ""
+echo "Done! The native Minecraft server is located at:"
+echo "${SCRIPT_DIR}/${BINARY_NAME}"

configuration/jni-config.json

@@ -0,0 +1,159 @@
+[
+{
+  "name":"[Lcom.sun.management.internal.DiagnosticCommandArgumentInfo;"
+},
+{
+  "name":"[Lcom.sun.management.internal.DiagnosticCommandInfo;"
+},
+{
+  "name":"com.sun.management.internal.DiagnosticCommandArgumentInfo",
+  "methods":[{"name":"<init>","parameterTypes":["java.lang.String","java.lang.String","java.lang.String","java.lang.String","boolean","boolean","boolean","int"] }]
+},
+{
+  "name":"com.sun.management.internal.DiagnosticCommandInfo",
+  "methods":[{"name":"<init>","parameterTypes":["java.lang.String","java.lang.String","java.lang.String","java.lang.String","java.lang.String","java.lang.String","boolean","java.util.List"] }]
+},
+{
+  "name":"io.netty.channel.ChannelException"
+},
+{
+  "name":"io.netty.channel.DefaultFileRegion",
+  "fields":[
+    {"name":"file"}, 
+    {"name":"transferred"}
+  ]
+},
+{
+  "name":"io.netty.channel.epoll.LinuxSocket"
+},
+{
+  "name":"io.netty.channel.epoll.Native"
+},
+{
+  "name":"io.netty.channel.epoll.NativeDatagramPacketArray$NativeDatagramPacket",
+  "fields":[
+    {"name":"count"}, 
+    {"name":"memoryAddress"}, 
+    {"name":"recipientAddr"}, 
+    {"name":"recipientAddrLen"}, 
+    {"name":"recipientPort"}, 
+    {"name":"recipientScopeId"}, 
+    {"name":"segmentSize"}, 
+    {"name":"senderAddr"}, 
+    {"name":"senderAddrLen"}, 
+    {"name":"senderPort"}, 
+    {"name":"senderScopeId"}
+  ]
+},
+{
+  "name":"io.netty.channel.epoll.NativeStaticallyReferencedJniMethods"
+},
+{
+  "name":"io.netty.channel.unix.Buffer"
+},
+{
+  "name":"io.netty.channel.unix.DatagramSocketAddress",
+  "methods":[{"name":"<init>","parameterTypes":["byte[]","int","int","int","io.netty.channel.unix.DatagramSocketAddress"] }]
+},
+{
+  "name":"io.netty.channel.unix.DomainDatagramSocketAddress",
+  "methods":[{"name":"<init>","parameterTypes":["byte[]","int","io.netty.channel.unix.DomainDatagramSocketAddress"] }]
+},
+{
+  "name":"io.netty.channel.unix.ErrorsStaticallyReferencedJniMethods"
+},
+{
+  "name":"io.netty.channel.unix.FileDescriptor"
+},
+{
+  "name":"io.netty.channel.unix.LimitsStaticallyReferencedJniMethods"
+},
+{
+  "name":"io.netty.channel.unix.PeerCredentials",
+  "methods":[{"name":"<init>","parameterTypes":["int","int","int[]"] }]
+},
+{
+  "name":"io.netty.channel.unix.Socket"
+},
+{
+  "name":"java.io.FileDescriptor",
+  "fields":[{"name":"fd"}]
+},
+{
+  "name":"java.io.IOException"
+},
+{
+  "name":"java.lang.Boolean",
+  "methods":[{"name":"getBoolean","parameterTypes":["java.lang.String"] }]
+},
+{
+  "name":"java.lang.ClassLoader",
+  "methods":[
+    {"name":"getPlatformClassLoader","parameterTypes":[] }, 
+    {"name":"loadClass","parameterTypes":["java.lang.String"] }
+  ]
+},
+{
+  "name":"java.lang.OutOfMemoryError"
+},
+{
+  "name":"java.lang.RuntimeException"
+},
+{
+  "name":"java.lang.SecurityManager",
+  "fields":[{"name":"initialized"}]
+},
+{
+  "name":"java.net.InetSocketAddress",
+  "methods":[{"name":"<init>","parameterTypes":["java.lang.String","int"] }]
+},
+{
+  "name":"java.net.PortUnreachableException"
+},
+{
+  "name":"java.nio.Buffer",
+  "fields":[
+    {"name":"limit"}, 
+    {"name":"position"}
+  ],
+  "methods":[
+    {"name":"limit","parameterTypes":[] }, 
+    {"name":"position","parameterTypes":[] }
+  ]
+},
+{
+  "name":"java.nio.DirectByteBuffer"
+},
+{
+  "name":"java.nio.channels.ClosedChannelException",
+  "methods":[{"name":"<init>","parameterTypes":[] }]
+},
+{
+  "name":"java.util.Arrays",
+  "methods":[{"name":"asList","parameterTypes":["java.lang.Object[]"] }]
+},
+{
+  "name":"jdk.internal.loader.ClassLoaders$PlatformClassLoader"
+},
+{
+  "name":"org.graalvm.jniutils.JNIExceptionWrapperEntryPoints",
+  "methods":[{"name":"getClassName","parameterTypes":["java.lang.Class"] }]
+},
+{
+  "name":"sun.management.VMManagementImpl",
+  "fields":[
+    {"name":"compTimeMonitoringSupport"}, 
+    {"name":"currentThreadCpuTimeSupport"}, 
+    {"name":"objectMonitorUsageSupport"}, 
+    {"name":"otherThreadCpuTimeSupport"}, 
+    {"name":"remoteDiagnosticCommandsSupport"}, 
+    {"name":"synchronizerUsageSupport"}, 
+    {"name":"threadAllocatedMemorySupport"}, 
+    {"name":"threadContentionMonitoringSupport"}
+  ]
+},
+{
+  "name":"sun.nio.ch.FileChannelImpl",
+  "fields":[{"name":"fd"}]
+}
+]

configuration/predefined-classes-config.json

@@ -0,0 +1,8 @@
+[
+  {
+    "type":"agent-extracted",
+    "classes":[
+    ]
+  }
+]
+

configuration/proxy-config.json

@@ -0,0 +1,2 @@
+[
+]

configuration/resource-config.json

@@ -0,0 +1,63 @@
+{
+  "resources":{
+  "includes":[
+    {
+      "pattern":"assets/.*"
+    },
+    {
+      "pattern":"data/.*"
+    },
+    {
+      "pattern":"\\QMETA-INF/MOJANGCS.SF\\E"
+    },
+    {
+      "pattern":"\\QMETA-INF/MOJANGCS.RSA\\E"
+    },
+    {
+      "pattern":"\\Qflightrecorder-config.jfc\\E"
+    },
+    {
+      "pattern":"\\QMETA-INF/libraries.list\\E"
+    },
+    {
+      "pattern":"\\QMETA-INF/native/libnetty_transport_native_epoll_x86_64.so\\E"
+    },
+    {
+      "pattern":"\\QMETA-INF/org/apache/logging/log4j/core/config/plugins/Log4j2Plugins.dat\\E"
+    },
+    {
+      "pattern":"\\QMETA-INF/services/java.nio.file.spi.FileSystemProvider\\E"
+    },
+    {
+      "pattern":"\\QMETA-INF/services/org.apache.logging.log4j.core.util.ContextDataProvider\\E"
+    },
+    {
+      "pattern":"\\QMETA-INF/services/org.apache.logging.log4j.spi.Provider\\E"
+    },
+    {
+      "pattern":"\\QMETA-INF/services/org.apache.logging.log4j.util.PropertySource\\E"
+    },
+    {
+      "pattern":"\\QMETA-INF/services/org.slf4j.spi.SLF4JServiceProvider\\E"
+    },
+    {
+      "pattern":"\\Qlog4j2.xml\\E"
+    },
+    {
+      "pattern":"\\Qoshi.architecture.properties\\E"
+    },
+    {
+      "pattern":"\\Qoshi.properties\\E"
+    },
+    {
+      "pattern":"\\Qversion.json\\E"
+    },
+    {
+      "pattern":"\\Qyggdrasil_session_pubkey.der\\E"
+    }
+  ]},
+  "bundles":[
+    { "name":"joptsimple.ExceptionMessages" },
+    { "name":"joptsimple.HelpFormatterMessages" }
+  ]
+}

configuration/serialization-config.json

@@ -0,0 +1,6 @@
+{
+  "types":[
+  ],
+  "lambdaCapturingTypes":[
+  ]
+}