Add rcon-cli support for server interaction

.gitattributes

@@ -0,0 +1,2 @@
+* text=auto
+*.sh text eol=lf

Dockerfile

@@ -25,6 +25,13 @@ ENV RENDER_SIGNS_JOINER "<br />"
 
 ENV CONFIG_LOCATION /home/minecraft/config.py
 
+# Install rcon-cli (https://github.com/itzg/rcon-cli). Perform a checksum check
+# to make sure it hasn't changed from underneath us.
+ENV RCON_CLI_URL "https://github.com/itzg/rcon-cli/releases/download/1.4.7/rcon-cli_1.4.7_linux_amd64.tar.gz"
+ENV RCON_CLI_SHA256 "cae03daceb3c463f0979ed0586778fb236cfbb83585413a9a06b1e83bceefa20"
+ENV RCON_CLI_ARGS_PRE_RENDER ""
+ENV RCON_CLI_ARGS_POST_RENDER ""
+
 RUN apt-get update && \
     apt-get install -y wget gnupg optipng && \
     echo "deb http://overviewer.org/debian ./" >> /etc/apt/sources.list && \
@@ -36,6 +43,12 @@ RUN apt-get update && \
     useradd -m minecraft -u 1000 -g 1000 && \
     mkdir -p /home/minecraft/render /home/minecraft/server
 
+# Install rcon-cli to support issuing RCON commands before/after the render
+RUN wget "${RCON_CLI_URL}" -O "/tmp/rcon-cli.tgz" && \
+    echo "${RCON_CLI_SHA256}  /tmp/rcon-cli.tgz" | sha256sum -c - && \
+    tar -xf /tmp/rcon-cli.tgz -C /usr/local/bin rcon-cli && \
+    rm /tmp/rcon-cli.tgz
+
 COPY config/config.py /home/minecraft/config.py
 COPY entrypoint.sh /home/minecraft/entrypoint.sh
 COPY download_url.py /home/minecraft/download_url.py

README.md

@@ -36,6 +36,12 @@ docker run \
 - `CONFIG_LOCATION`
   Default Value: `/home/minecraft/config.py`. Set to a different path to override the provided configuration. This only makes sense if you have a different configuration in a volume.
 
+- `RCON_CLI_ARGS_POST_RENDER`
+  Default Value: _null_. Set to contain any [Minecraft RCON](https://wiki.vg/RCON) command you'd like to have run after the render completes. This uses [`itzg/rcon-cli`](https://github.com/itzg/rcon-cli), so please refer to that project for full list of available options. Could be used to issue `save on` to re-enable file writes once done rendering.
+
+- `RCON_CLI_ARGS_PRE_RENDER`
+  Default Value: _null_. Set to contain any [Minecraft RCON](https://wiki.vg/RCON) command you'd like to have run before the render starts. This uses [`itzg/rcon-cli`](https://github.com/itzg/rcon-cli), so please refer to that project for full list of available options. Could be used to issue `save off` to prevent file changes while rendering.
+
 - `RENDER_MAP`
   Default Value: `true`. Set to `false` if you do not want to render the map. This is useful for POI only-updates.
 

entrypoint.sh

@@ -39,6 +39,12 @@ if grep -q "texturepath" "${CONFIG_LOCATION}"; then
   cp "${NEW_LOCATION}" "${OLD_LOCATION}"
 fi
 
+if [ -n "$RCON_CLI_ARGS_PRE_RENDER" ]; then
+  echo "Running rcon-cli before starting render..."
+  # shellcheck disable=SC2086
+  rcon-cli $RCON_CLI_ARGS_PRE_RENDER
+fi
+
 # Render the Map
 if [ "$RENDER_MAP" == "true" ]; then
   overviewer.py --config "$CONFIG_LOCATION" $ADDITIONAL_ARGS
@@ -48,3 +54,9 @@ fi
 if [ "$RENDER_POI" == "true" ]; then
   overviewer.py --config "$CONFIG_LOCATION" --genpoi $ADDITIONAL_ARGS_POI
 fi
+
+if [ -n "$RCON_CLI_ARGS_POST_RENDER" ]; then
+  echo "Running rcon-cli after finishing render..."
+  # shellcheck disable=SC2086
+  rcon-cli $RCON_CLI_ARGS_POST_RENDER
+fi