Add REMOVE_OLD_CONFIGS to clear old configs before modpack install (#4266)

docs/mods-and-plugins/index.md

@@ -66,6 +66,8 @@ You can also specify the `REMOVE_OLD_MODS_DEPTH` (default is 16) variable to onl
 
 For example: `-e REMOVE_OLD_MODS=TRUE -e REMOVE_OLD_MODS_INCLUDE="*.jar" -e REMOVE_OLD_MODS_DEPTH=1` will remove all old jar files that are directly inside the `plugins/` or `mods/` directory.
 
+To remove all files in the `/data/config` directory before a modpack is downloaded and unpacked, set `REMOVE_OLD_CONFIGS=TRUE`. This is useful when a modpack update would otherwise override locally customized configuration files. The removal process can be fine tuned with `REMOVE_OLD_CONFIGS_INCLUDE` and `REMOVE_OLD_CONFIGS_EXCLUDE` (comma separated lists of file glob patterns, defaults to `*` so everything is removed) and `REMOVE_OLD_CONFIGS_DEPTH` (default 16). The target directory can be changed with `CONFIG_OUT_DIR` (default `/data/config`).
+
 These paths work well if you want to have a common set of modules in a separate location, but still have multiple worlds with different server requirements in either persistent volumes or a downloadable archive.
 
 !!! information "Multiple source directories"

scripts/start-setupModpack

@@ -9,6 +9,11 @@ set -e -o pipefail
 : "${PLUGINS_FILE:=}"
 : "${REMOVE_OLD_MODS_DEPTH:=1} "
 : "${REMOVE_OLD_MODS_INCLUDE:=*.jar,*-version.json}"
+: "${REMOVE_OLD_CONFIGS:=false}"
+: "${CONFIG_OUT_DIR:=/data/config}"
+: "${REMOVE_OLD_CONFIGS_DEPTH:=16}"
+: "${REMOVE_OLD_CONFIGS_INCLUDE:=*}"
+: "${REMOVE_OLD_CONFIGS_EXCLUDE:=}"
 : "${CF_USE_HTTP2:=false}" # CF downloads are faster with HTTP 1.1
 : "${MODRINTH_LOADER:=}"
 
@@ -25,6 +30,10 @@ if isTrue "${REMOVE_OLD_MODS}" && [ -z "${MODS_FILE}" ]; then
   rm -f "$sum_file"
 fi
 
+if isTrue "${REMOVE_OLD_CONFIGS}"; then
+  removeOldConfigs "$CONFIG_OUT_DIR"
+fi
+
 function handlePackwiz() {
   # If packwiz url passed, bootstrap packwiz and update mods before other modpack processing
   if [[ "${PACKWIZ_URL:-}" ]]; then

scripts/start-utils

@@ -547,6 +547,23 @@ function removeOldMods {
   fi
 }
 
+function removeOldConfigs {
+  if [ -d "$1" ]; then
+    log "Removing old configs including='${REMOVE_OLD_CONFIGS_INCLUDE}' excluding='${REMOVE_OLD_CONFIGS_EXCLUDE}' up to depth=${REMOVE_OLD_CONFIGS_DEPTH}"
+    args=(
+      --delete
+      --type file
+      --min-depth=1 --max-depth "${REMOVE_OLD_CONFIGS_DEPTH}"
+      --name "${REMOVE_OLD_CONFIGS_INCLUDE}"
+      --exclude-name "${REMOVE_OLD_CONFIGS_EXCLUDE}"
+    )
+    if ! isDebugging; then
+      args+=(--quiet)
+    fi
+    mc-image-helper find "${args[@]}" "$1"
+  fi
+}
+
 function get() {
   mc-image-helper get "$@"
 }

tests/setuponlytests/remove-old-configs/docker-compose.yml

@@ -0,0 +1,43 @@
+services:
+  # copies an existing config into /data before mc starts, so REMOVE_OLD_CONFIGS
+  # has an old config to remove once the modpack config is installed
+  seed:
+    restart: "no"
+    image: ${IMAGE_TO_TEST:-itzg/minecraft-server}
+    entrypoint: ["bash", "-c", "mkdir -p /data/config && cp /seed/config/stale.txt /data/config/ && chown -R 1000:1000 /data"]
+    volumes:
+      - ./seed:/seed
+      - ./data:/data
+
+  web:
+    image: nginx
+    volumes:
+      - ./configs.zip:/usr/share/nginx/html/configs.zip:ro
+    healthcheck:
+      test: ["CMD", "curl", "--fail", "http://localhost/configs.zip"]
+      interval: 3s
+      timeout: 5s
+      retries: 3
+
+  mc:
+    restart: "no"
+    image: ${IMAGE_TO_TEST:-itzg/minecraft-server}
+    depends_on:
+      seed:
+        condition: service_completed_successfully
+      web:
+        condition: service_healthy
+    environment:
+      EULA: "true"
+      SETUP_ONLY: "true"
+      GENERIC_PACKS: http://web/configs.zip
+      REMOVE_OLD_CONFIGS: "true"
+      LOG_TIMESTAMP: "true"
+      # the following are only used to speed up test execution
+      TYPE: CUSTOM
+      CUSTOM_SERVER: /servers/fake.jar
+      VERSION: 1.18.1
+      DEBUG: "true"
+    volumes:
+      - ./data:/data
+      - ./fake.jar:/servers/fake.jar

tests/setuponlytests/remove-old-configs/seed/config/stale.txt

@@ -0,0 +1 @@
+old

tests/setuponlytests/remove-old-configs/verify.sh

@@ -0,0 +1,3 @@
+# verify that the old config was removed and the new one from the pack was installed
+mc-image-helper assert fileNotExists config/stale.txt
+mc-image-helper assert fileExists config/opt.yml