Add linter workflow

.github/workflows/cd.yaml

@@ -1,6 +1,6 @@
 name: CD
 
-on:
+on: # yamllint disable-line rule:truthy
   push:
     tags:
       - 'v*'

.github/workflows/ci.yaml

@@ -1,6 +1,6 @@
 name: CI
 
-on:
+on: # yamllint disable-line rule:truthy
   push:
     branches:
       - master
@@ -16,7 +16,7 @@ env:
 
 jobs:
   build:
-    name: CI
+    name: Build
     runs-on: ubuntu-latest
 
     services:

.github/workflows/docker_release.yml

@@ -4,7 +4,7 @@ permissions:
   contents: read
   packages: write
 
-on:
+on: # yamllint disable-line rule:truthy
   workflow_call:
     inputs:
       registry:
@@ -55,8 +55,8 @@ jobs:
     steps:
       - name: Prepare
         run: |
-          platform=${{ matrix.platform }}
-          echo "PLATFORM_PAIR=${platform//\//-}" >> $GITHUB_ENV
+          platform="${{ matrix.platform }}"
+          echo "PLATFORM_PAIR=${platform//\//-}" >> "${GITHUB_ENV}"
 
       - name: Checkout
         uses: actions/checkout@v4
@@ -158,5 +158,5 @@ jobs:
       - name: Create Manifest List and Push
         working-directory: /tmp/digests
         run: |
-          docker buildx imagetools create $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
-            $(printf '${{ env.REGISTRY_IMAGE }}@sha256:%s ' *)
+          docker buildx imagetools create "$(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "${DOCKER_METADATA_OUTPUT_JSON}")" \
+            "$(printf '${{ env.REGISTRY_IMAGE }}@sha256:%s ' *)"

.github/workflows/lint.yml

@@ -0,0 +1,81 @@
+name: CI
+
+on: # yamllint disable-line rule:truthy
+  pull_request:
+    types: [opened, synchronize, reopened]
+
+jobs:
+  hadolint:
+    name: Hadolint
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Lint
+        uses: reviewdog/action-hadolint@v1
+        with:
+          reporter: github-pr-check
+          filter_mode: nofilter
+          reviewdog_flags: '-fail-level=any'
+
+  shellcheck:
+    name: ShellCheck
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Lint
+        uses: reviewdog/action-shellcheck@v1
+        with:
+          reporter: github-pr-check
+          filter_mode: nofilter
+          reviewdog_flags: '-fail-level=any'
+
+  markdownlint:
+    name: MarkdownLint
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Lint
+        uses: reviewdog/action-markdownlint@v0
+        with:
+          reporter: github-pr-check
+          filter_mode: nofilter
+          reviewdog_flags: '-fail-level=any'
+
+  yamllint:
+    name: YamlLint
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Lint
+        uses: reviewdog/action-yamllint@v1
+        with:
+          reporter: github-pr-check
+          filter_mode: nofilter
+          reviewdog_flags: '-fail-level=any'
+
+  actionlint:
+    name: ActionLint
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Lint
+        uses: reviewdog/action-actionlint@v1
+        with:
+          reporter: github-pr-check
+          filter_mode: nofilter
+          reviewdog_flags: '-fail-level=any'

.markdownlint.yaml

@@ -0,0 +1,7 @@
+# MD013/line-length : Line length : https://github.com/DavidAnson/markdownlint/blob/v0.36.1/doc/md013.md
+MD013:
+  # Number of characters
+  line_length: 140
+
+# MD028/no-blanks-blockquote : Blank line inside blockquote : https://github.com/DavidAnson/markdownlint/blob/v0.36.1/doc/md028.md
+MD028: false

.yamllint

@@ -0,0 +1,6 @@
+rules:
+  # https://yamllint.readthedocs.io/en/stable/rules.html#module-yamllint.rules.document_start
+  document-start: disable
+  line-length:
+    max: 140
+    allow-non-breakable-words: true

README.md

@@ -1,6 +1,7 @@
 # Docker Minecraft FTB
 
-A Docker image developed to launch Minecraft [FTB](https://www.feed-the-beast.com/) Modpack servers as safely, quickly and easily as possible.
+A Docker image developed to launch Minecraft [FTB](https://www.feed-the-beast.com/) Modpack servers as safely, quickly and easily as
+possible.
 
 ## Features
 
@@ -50,13 +51,16 @@ services:
 ## Notes
 
 > [!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).
+> 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.
+> 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.
+> 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
 
@@ -65,7 +69,9 @@ services:
 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`.
+> 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`
 
@@ -80,17 +86,20 @@ Default: Latest version of the configured modpack.
 
 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.
+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`.
 
 ### `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 `-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.
+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`.
 
@@ -103,7 +112,8 @@ Default: *none*
 
 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.
+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`
 
@@ -112,7 +122,8 @@ Default: `0`
 Set `1` to force a reinstallation of the modpack when the container is started.
 
 > [!WARNING]
-> This option should only be used in special cases, as constantly reinstalling the modpack significantly slows down the start of the container.
+> This option should only be used in special cases, as constantly reinstalling the modpack significantly slows down the start of the
+> container.
 
 Default: `0`
 

minecraft-ftb/data/Dockerfile

@@ -5,12 +5,13 @@ FROM debian:bookworm-slim
 ENV FTB_MODPACK_ID=0
 ENV FTB_MODPACK_VERSION_ID=0
 ENV ACCEPT_MOJANG_EULA=0
-ENV USER_JVM_ARGS=
+ENV USER_JVM_ARGS=""
 ENV AUTO_UPDATE=0
 ENV FORCE_REINSTALL=0
 
 # Set up runtime dependencies
 
+# hadolint ignore=DL3008
 RUN set -eux; \
 	apt-get update; \
 	apt-get install -y --no-install-recommends \
@@ -22,6 +23,7 @@ RUN set -eux; \
 
 # Set up container user
 
+# hadolint ignore=DL3008
 RUN set -eux; \
 	groupadd --gid 99 --system minecraft; \
 	useradd \

minecraft-ftb/data/docker-entrypoint.sh

@@ -10,11 +10,11 @@ ansi_g="\e[92m"
 ansi_r="\e[31m"
 
 echoerr() {
-    echo -e "${ansi_r}ERROR:${ansi_rst} $@" 1>&2;
+    echo -e "${ansi_r}ERROR:${ansi_rst} $*" 1>&2;
 }
 
 echoinfo() {
-    echo -e "${ansi_b}INFO:${ansi_rst} $@"
+    echo -e "${ansi_b}INFO:${ansi_rst} $*"
 }
 
 check_environment() {
@@ -51,8 +51,8 @@ fetch_modpack_info() {
     local response
     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 [${ansi_green}$1${ansi_rst}] is correct."
+    if [ -z "${response}" ] || [ "$(echo "${response}" | jq -r '.status')" != "success" ]; then
+        echoerr "Failed to fetch modpack info. Please check if the modpack id [${ansi_g}$1${ansi_rst}] is correct."
         echoerr "$(echo "${response}" | jq -r '.message')"
         return 1
     fi
@@ -63,6 +63,7 @@ fetch_modpack_info() {
 # $1 = modpack info JSON payload
 # rt = latest modpack version id
 query_latest_version_id() {
+    # shellcheck disable=SC2155
     local result=$(echo "$1" | jq -r '[.versions | sort_by(.updated) | reverse | .[] | select(.type == "Release" and .private == false) | .id][0]')
 
     if [ -z "${result}" ]; then
@@ -77,10 +78,11 @@ query_latest_version_id() {
 # $2 = modpack version id
 # rt = modpack version info JSON payload
 query_version_info() {
+    # shellcheck disable=SC2155
     local result=$(echo "$1" | jq -r ".versions[] | select(.id == $2)")
 
     if [ -z "${result}" ]; then
-        echoerr "Failed to query version info. Please check if the modpack version id [${ansi_green}$2${ansi_rst}] is correct."
+        echoerr "Failed to query version info. Please check if the modpack version id [${ansi_g}$2${ansi_rst}] is correct."
         return 1
     fi
 
@@ -132,21 +134,21 @@ patch_start_script() {
         output+="${line}\n"
     done < start.sh
 
-    if [ ! success ]; then
+    if [ ! "${success}" ]; then
         echoerr "Failed to patch 'start.sh' script."
         echoerr "Please open an issue here: https://github.com/flobernd/docker-minecraft-ftb"
         return 1
     fi
 
-    printf "${output}" > /var/lib/minecraft/start.sh
+    printf "%s" "${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 "# 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
 }
 
@@ -171,7 +173,7 @@ 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 [${ansi_green}${local_pack_id}${ansi_rst}] does not " \
+            echoerr "A modpack is already installed, but the modpack id [${ansi_g}${local_pack_id}${ansi_rst}] does not " \
                     "match the configured modpack id [${ansi_green}${target_pack_id}${ansi_rst}]."
             exit 1
         fi
@@ -208,7 +210,8 @@ if [ "$1" = "/var/lib/minecraft/start.sh" ]; then
     if [ "${local_pack_id}" -eq 0 ] || [ "${FORCE_REINSTALL}" == 1 ]; then
         echo -e "Installing modpack version '${ansi_b}${target_version_name}${ansi_rst}' [${ansi_g}${target_version_id}${ansi_rst}]"
 
-        if [ "${FORCE_REINSTALL}" != 1 ] && [ $(ls -A . | wc -l) -ne 0 ]; then
+        # shellcheck disable=SC2012
+        if [ "${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."
             echoerr "To continue, set the 'FORCE_REINSTALL' environment variable to '1' and retry."
             exit 1