Add USER_JVM_ARGS

flobernd · Nov 18, 2024 · 9f6c220 · 9f6c220
1 parent ed5b345
commit 9f6c220
Show file tree

Hide file tree

Showing 5 changed files with 102 additions and 44 deletions.
diff --git a/README.md b/README.md
@@ -1,29 +1,32 @@
 # Docker Minecraft FTB
 
-A Docker image for running [FTB](https://www.feed-the-beast.com/) Minecraft servers.
+A Docker image developed to launch Minecraft [FTB](https://www.feed-the-beast.com/) Modpack servers as safely, quickly and easily as possible.
 
-### Example
+## Features
+
+- Supports all "Feed The Beast" (FTB) [modpacks](https://www.feed-the-beast.com/modpacks?sort=featured)
+- Configurable modpack versions
+  - Allows pinning to a specific modpack version (see `FTB_MODPACK_VERSION_ID`)
+  - Installs the latest version of the modpack, if no specific version is configured
+- Supports automatic modpack upgrades on container start (see `AUTO_UPDATE`)
+- Supports unattended installation (see `ACCEPT_MOJANG_EULA`)
+- Supports configuration of user-defined JVM arguments as part of the container configuration (see `USER_JVM_ARGS`)
+- Drops `root` privileges after setting up the container and runs the server as an unprivileged user
+
+## Example
 
 ```bash
 docker run -itd --name minecraft-ftb \
     -v "/docker_data/minecraft:/var/lib/minecraft" \
     -e "FTB_MODPACK_ID=126" \
     -e "ACCEPT_MOJANG_EULA=1" \
+    -e "USER_JVM_ARGS=-Xms1G -Xmx4G" \
     -p "25565:25565" \
     --stop-timeout=60 \
     ghcr.io/flobernd/minecraft-ftb
 ```
 
-> [!WARNING]
-> The server process does not shut down gracefully, if no TTY is present. Please pass the `--tty`/`-t` switch (Docker) or use `tty: true` (Docker Compose).
-
-> [!WARNING]
-> It is strongly recommended to set the `stop-timeout` / `stop_grace_period` to at least `60` seconds to avoid data loss when stopping the container.
-
-> [!NOTE]
-> It is recommended to pass the `--interactive`/`-i` switch (Docker) or use `stdin_open: true` (Docker Compose) to be able to use the server console after attaching to the container.
-
-### Docker Compose Example
+## Docker Compose Example
 
 ```yaml
 services:
@@ -35,24 +38,36 @@ services:
     stdin_open: true
     stop_grace_period: 1m
     environment:
-      - "FTB_MODPACK_ID=126"
-      - "ACCEPT_MOJANG_EULA=1"
+      FTB_MODPACK_ID: 126
+      ACCEPT_MOJANG_EULA: 1
+      USER_JVM_ARGS: "-Xms1G -Xmx4G"
     volumes:
       - ./minecraft:/var/lib/minecraft:rw
     ports:
       - 25565:25565
 ```
 
-### Environment
+## Notes
 
-#### `FTB_MODPACK_ID`
+> [!WARNING]
+> The server process does not shut down gracefully, if no TTY is present. Please pass the `--tty`/`-t` switch (Docker) or use `tty: true` (Docker Compose).
+
+> [!WARNING]
+> It is strongly recommended to set the `stop-timeout` (Docker) / `stop_grace_period` (Docker Compose) to at least `60` seconds to avoid data loss when stopping the container.
+
+> [!NOTE]
+> It is recommended to pass the `--interactive`/`-i` switch (Docker) or use `stdin_open: true` (Docker Compose) to be able to use the server console after attaching to the container.
+
+## Environment
+
+### `FTB_MODPACK_ID`
 
 The FTB modpack ID (*required*).
 
 > [!NOTE]
 > The modpack ID and the version ID are displayed on the right-hand side of the modpack info page. For example, the [Direwolf20 1.21 modpack](https://www.feed-the-beast.com/modpacks/126-ftb-presents-direwolf20-121) has the ID `126` and the latest version, as of today, is `12599`.
 
-#### `FTB_MODPACK_VERSION_ID`
+### `FTB_MODPACK_VERSION_ID`
 
 The FTB modpack version ID.
 
@@ -61,23 +76,38 @@ The FTB modpack version ID.
 
 Default: Latest version of the configured modpack.
 
-#### `ACCEPT_MOJANG_EULA`
+### `ACCEPT_MOJANG_EULA`
 
 Set `1` to automatically agree to the [Mojang EULA](https://account.mojang.com/documents/minecraft_eula).
 
 This option enables unattended installation. Otherwise, an interactive session must be used to accept the EULA after installation, or the `eula.txt` must be edited manually and the container restarted.
 
 Default: `0`.
 
-#### `AUTO_UPDATE`
+### `USER_JVM_ARGS`
+
+Optional, user-defined JVM arguments.
+
+Use the `-Xms` switch to configure the minimum amount of memory used by the JVM. `-Xms1G` sets the minimum amount of memory to 1 GB. The `M` suffix can be used to specify the amount of memory in megabytes instead of gigabytes.
+
+Use the `-Xmx` switch to configure the maximum amount of memory used by the JVM. `-Xms4G` sets the maximum amount of memory to 4 GB. The `M` suffix can be used to specify the amount of memory in megabytes instead of gigabytes.
+
+To specify multiple arguments, combine them with spaces: `-Xms1G -Xmx4G`.
+
+> [!WARNING]
+> Using this option causes the `user_jvm_args.txt` file to be overwritten when the container is started.
+
+Default: *none*
+
+### `AUTO_UPDATE`
 
 Set `1` to automatically update the modpack when the container is started.
 
 If `FTB_MODPACK_VERSION_ID` is set, the configured version number is used, otherwise the latest version of the modpack is determined automatically.
 
 Default: `0`
 
-#### `FORCE_REINSTALL`
+### `FORCE_REINSTALL`
 
 Set `1` to force a reinstallation of the modpack when the container is started.
 

diff --git a/minecraft-ftb/data/Dockerfile b/minecraft-ftb/data/Dockerfile
@@ -4,11 +4,10 @@ FROM debian:bookworm-slim
 
 ENV FTB_MODPACK_ID=0
 ENV FTB_MODPACK_VERSION_ID=0
-
 ENV ACCEPT_MOJANG_EULA=0
-
-ENV JAVA_MEMORY_MIN=
-ENV JAVA_MEMORY_MAX=
+ENV USER_JVM_ARGS=
+ENV AUTO_UPDATE=0
+ENV FORCE_REINSTALL=0
 
 # Set up runtime dependencies
 

diff --git a/minecraft-ftb/data/docker-entrypoint.sh b/minecraft-ftb/data/docker-entrypoint.sh
@@ -1,10 +1,20 @@
 #!/bin/bash
 
 set -o pipefail
+set -o nounset
 set -e
 
+ansi_rst="\e[0m"
+ansi_b="\e[94m"
+ansi_g="\e[92m"
+ansi_r="\e[31m"
+
 echoerr() {
-    echo "ERROR: $@" 1>&2;
+    echo -e "${ansi_r}ERROR:${ansi_rst} $@" 1>&2;
+}
+
+echoinfo() {
+    echo -e "${ansi_b}INFO:${ansi_rst} $@"
 }
 
 check_environment() {
@@ -17,7 +27,7 @@ check_environment() {
     do
         if [ -z "${!value}" ]; then
             missing=true
-            echoerr "Missing mandatory environment variable: '${value}'"
+            echoerr "Missing mandatory environment variable: '${ansi_b}${value}${ansi_rst}'"
         fi
     done
 
@@ -42,7 +52,7 @@ fetch_modpack_info() {
     response=$(curl --fail --connect-timeout 30 --max-time 30 --no-progress-meter "https://api.modpacks.ch/public/modpack/$1") || exit $?
 
     if [ -z "${response}" ] || [ $(echo "${response}" | jq -r '.status') != "success" ]; then
-        echoerr "Failed to fetch modpack info. Please check if the modpack id [$1] is correct."
+        echoerr "Failed to fetch modpack info. Please check if the modpack id [${ansi_green}$1${ansi_rst}] is correct."
         echoerr "$(echo "${response}" | jq -r '.message')"
         return 1
     fi
@@ -70,7 +80,7 @@ query_version_info() {
     local result=$(echo "$1" | jq -r ".versions[] | select(.id == $2)")
 
     if [ -z "${result}" ]; then
-        echoerr "Failed to query version info. Please check if the modpack version id [$2] is correct."
+        echoerr "Failed to query version info. Please check if the modpack version id [${ansi_green}$2${ansi_rst}] is correct."
         return 1
     fi
 
@@ -108,18 +118,18 @@ patch_start_script() {
     # We have to make sure the `start.sh` script uses `exec` to launch the server. SIGINT and
     # other signals would not be forwarded to the Java process otherwise.
 
-    regex='^("jre/.+/bin/java" .+ nogui)$'
-    output=""
-    success=false
+    local regex='^("jre/.+/bin/java" .+ nogui)$'
+    local output=""
+    local success=false
 
-    while IFS="" read -r line || [ -n "$line" ]
+    while IFS="" read -r line || [ -n "${line}" ]
     do
         if [[ $line =~ $regex ]]; then
             output+="exec "
             success=true
         fi
 
-        output+="$line\n"
+        output+="${line}\n"
     done < start.sh
 
     if [ ! success ]; then
@@ -128,7 +138,16 @@ patch_start_script() {
         return 1
     fi
 
-    printf "$output" > start.sh
+    printf "${output}" > /var/lib/minecraft/start.sh
+}
+
+update_user_jvm_args() {
+    if [ -z "${USER_JVM_ARGS}" ]; then
+        exit 0
+    fi
+
+    printf "# Generated by "docker-minecraft-ftb"; DO NOT EDIT.\n\n" > /var/lib/minecraft/user_jvm_args.txt
+    printf "%s" "${USER_JVM_ARGS}" | xargs -n 1 printf "%s\n" >> /var/lib/minecraft/user_jvm_args.txt
 }
 
 if [ "$1" = "/var/lib/minecraft/start.sh" ]; then
@@ -152,7 +171,8 @@ if [ "$1" = "/var/lib/minecraft/start.sh" ]; then
         fi
 
         if [ "${local_pack_id}" -ne "${target_pack_id}" ]; then
-            echoerr "A modpack is already installed, but the modpack id [${local_pack_id}] does not match the configured modpack id [${target_pack_id}]."
+            echoerr "A modpack is already installed, but the modpack id [${ansi_green}${local_pack_id}${ansi_rst}] does not " \
+                    "match the configured modpack id [${ansi_green}${target_pack_id}${ansi_rst}]."
             exit 1
         fi
     fi
@@ -162,7 +182,7 @@ if [ "$1" = "/var/lib/minecraft/start.sh" ]; then
     modpack_info=$(fetch_modpack_info "${target_pack_id}")
     modpack_name=$(echo "${modpack_info}" | jq -r '.name')
 
-    echo "Selected modpack '${modpack_name}' [${target_pack_id}]"
+    echo -e "Selected modpack '${ansi_b}${modpack_name}${ansi_rst}' [${ansi_g}${target_pack_id}${ansi_rst}]"
 
     # Query latest version
 
@@ -186,7 +206,7 @@ if [ "$1" = "/var/lib/minecraft/start.sh" ]; then
     # Install modpack
 
     if [ "${local_pack_id}" -eq 0 ] || [ "${FORCE_REINSTALL}" == 1 ]; then
-        echo "Installing modpack version '${target_version_name}' [${target_version_id}]"
+        echo -e "Installing modpack version '${ansi_b}${target_version_name}${ansi_rst}' [${ansi_g}${target_version_id}${ansi_rst}]"
 
         if [ "${FORCE_REINSTALL}" != 1 ] && [ $(ls -A . | wc -l) -ne 0 ]; then
             echoerr "The destination directory is not empty. Installing the modpack could lead to data loss."
@@ -207,15 +227,19 @@ if [ "$1" = "/var/lib/minecraft/start.sh" ]; then
     # Prevent modpack downgrade
 
     if [ "${local_version_id}" -gt "${target_version_id}" ]; then
-        echoerr "Detected downgrade from version '${local_version_name}' [${local_version_id}] to '${target_version_name}' [${target_version_id}]."
+        echoerr "Detected downgrade from version " \
+                "'${ansi_b}${local_version_name}${ansi_rst}' [${ansi_g}${local_version_id}${ansi_rst}] to " \
+                "'${ansi_b}${target_version_name}${ansi_rst}' [${ansi_g}${target_version_id}${ansi_rst}]."
         echoerr "To continue, set the 'FORCE_REINSTALL' environment variable to '1' and retry."
         exit 1
     fi
 
     # Upgrade modpack
 
     if [ "${local_version_id}" -lt "${target_version_id}" ]; then
-        echo "Upgrading modpack from version '${local_version_name}' [${local_version_id}] to '${target_version_name}' [${target_version_id}]."
+        echo -e "Upgrading modpack from version " \
+                "'${ansi_b}${local_version_name}${ansi_rst}' [${ansi_g}${local_version_id}${ansi_rst}] to " \
+                "'${ansi_b}${target_version_name}${ansi_rst}' [${ansi_g}${target_version_id}${ansi_rst}]."
 
         get_and_run_installer "${target_pack_id}" "${target_version_id}"
         local_version_id="${target_version_id}"
@@ -225,7 +249,7 @@ if [ "$1" = "/var/lib/minecraft/start.sh" ]; then
     # Show info, if a newer version is available
 
     if [ "${local_version_id}" -lt "${latest_version_id}" ]; then
-        echo "INFO: A newer version '${latest_version_name}' [${latest_version_id}] is available."
+        echoinfo "A newer version '${ansi_b}${latest_version_name}${ansi_rst}' [${ansi_g}${latest_version_id}${ansi_rst}] is available."
     fi
 
     # Accept Mojang EULA
@@ -235,11 +259,14 @@ if [ "$1" = "/var/lib/minecraft/start.sh" ]; then
         chown minecraft:minecraft eula.txt
     fi
 
-    # TODO: Set- or update memory arguments in user_jvm_args.txt
+    # Set- or update JVM arguments in `user_jvm_args.txt`
+
+    update_user_jvm_args
 
     # Start modpack
 
-    echo "Starting modpack '${modpack_name}' (${target_pack_id}) version '${local_version_name}' [${local_version_id}]"
+    echo -e "Starting modpack '${ansi_b}${modpack_name}${ansi_rst}' [${ansi_g}${target_pack_id}${ansi_rst}] " \
+            "version '${ansi_b}${local_version_name}${ansi_rst}' [${ansi_g}${local_version_id}${ansi_rst}]"
 fi
 
 # Execute command on behalf of the 'minecraft' user

diff --git a/minecraft-ftb/docker-compose.yml b/minecraft-ftb/docker-compose.yml
@@ -7,8 +7,9 @@ services:
     stdin_open: true
     stop_grace_period: 1m
     environment:
-      - "FTB_MODPACK_ID=126"
-      - "ACCEPT_MOJANG_EULA=1"
+      FTB_MODPACK_ID: 126
+      ACCEPT_MOJANG_EULA: 1
+      USER_JVM_ARGS: "-Xms1G -Xmx4G"
     volumes:
       - ./volume:/var/lib/minecraft:rw
     ports:

diff --git a/minecraft-ftb/run.sh b/minecraft-ftb/run.sh
@@ -6,6 +6,7 @@ docker run -it --rm --name minecraft-ftb \
     -v "$SCRIPT_DIR/volume:/var/lib/minecraft" \
     -e "FTB_MODPACK_ID=126" \
     -e "ACCEPT_MOJANG_EULA=1" \
+    -e "USER_JVM_ARGS=-Xms1G -Xmx4G" \
     -p "25565:25565" \
     --stop-timeout=60 \
     flobernd/minecraft-ftb