RCON commands feature (#1391)

Co-authored-by: christopher blodgett <christopher.blodgett@gmail.com>

Dockerfile

@@ -72,8 +72,9 @@ COPY --chmod=644 files/server.properties /tmp/server.properties
 COPY --chmod=644 files/log4j2.xml /tmp/log4j2.xml
 COPY --chmod=755 files/autopause /autopause
 COPY --chmod=755 files/autostop /autostop
+COPY --chmod=755 files/rconcmds /rconcmds
 
-RUN dos2unix /start* /autopause/* /autostop/*
+RUN dos2unix /start* /autopause/* /autostop/* /rconcmds/*
 
 ENTRYPOINT [ "/start" ]
 HEALTHCHECK --start-period=1m CMD mc-health

README.md

@@ -1657,6 +1657,50 @@ To also include the timestamp with each log, set `LOG_TIMESTAMP` to "true". The
 [init] 2022-02-05 16:58:33+00:00 Starting the Minecraft server...
 ```
 
+### Use RCON commands
+
+Feature is used run commands when the server starts, client connects, or client disconnects.
+**Notes:**
+* On clinet connect we only know there was a connection, and not who connected. RCON commands will need to be used for that.
+* Using '|-' is preferred for yaml, this make sure only the correct new lines are in place for the commands.
+
+**On Server Start:**
+
+```yaml
+      RCON_CMDS_STARTUP:  |-
+        /gamerule doFireTick false
+```
+
+**On Client Connection:**
+
+```yaml
+      RCON_CMDS_ON_CONNECT:  |-
+        /team join New @a[team=]
+```
+
+**On Client Disconnect:**
+
+```yaml
+      RCON_CMDS_ON_DISCONNECT:  |-
+        /gamerule doFireTick true
+```
+
+**Example of rules for new players**
+
+Uses team NEW and team OLD to track players on the server. So move player with no team to NEW, run a command, move them to team OLD.
+[Reference Article](https://www.minecraftforum.net/forums/minecraft-java-edition/redstone-discussion-and/2213523-detect-players-first-join)
+
+```yaml
+      RCON_CMDS_STARTUP:  |-
+        /gamerule doFireTick false
+        /team add New
+        /team add Old
+      RCON_CMDS_ON_CONNECT: |-
+        /team join New @a[team=]
+        /give @a[team=New] diamond_block
+        /team join Old @a[team=New]
+```
+
 ## Autopause
 
 ### Description

examples/docker-compose-rconcmd.yml

@@ -0,0 +1,24 @@
+version: '3'
+
+services:
+  minecraft:
+    image: ${IMAGE_TO_TEST:-itzg/minecraft-server}
+    ports:
+      - "25565:25565"
+    volumes:
+      - "mc:/data"
+    environment:
+      EULA: "TRUE"
+      # YAML Heredoc, be sure to use '|-' this will remove the first newline and final new line.
+      # This is versus '|' that will leaving with two empty strings at top and bottom.
+      RCON_CMDS_STARTUP:  |-
+        /gamerule doFireTick false
+        /team add New
+        /team add Old
+      RCON_CMDS_ON_CONNECT: |-
+        /team join New @a[team=]
+        /give @a[team=New] diamond_block
+        /team join Old @a[team=New]
+    restart: unless-stopped
+volumes:
+  mc: {}

files/autopause/autopause-fcns.sh

@@ -20,12 +20,16 @@ mc_server_listening() {
   mc-monitor status --host localhost --port "$SERVER_PORT" --timeout 10s >& /dev/null
 }
 
-java_clients_connected() {
+java_clients_connections() {
   local connections
   if java_running ; then
     connections=$(mc-monitor status --host localhost --port "$SERVER_PORT" --show-player-count)
   else
     connections=0
   fi
-  (( connections > 0 ))
+  echo $connections
+}
+
+java_clients_connected() {
+  (( $(java_clients_connections) > 0 ))
 }

files/rconcmds/rcon-cmds-daemon.sh

@@ -0,0 +1,75 @@
+#!/bin/bash
+
+: "${RCON_CMDS_STARTUP:=}"
+: "${RCON_CMDS_ON_CONNECT:=}"
+: "${RCON_CMDS_ON_DISCONNECT:=}"
+: "${RCON_CMDS_PERIOD:=10}"
+
+# needed for the clients connected function residing in autopause
+# shellcheck source=/autopause/autopause-fcns.sh
+. /autopause/autopause-fcns.sh
+
+# shellcheck source=start-utils
+. ${SCRIPTS:-/}start-utils
+
+run_command(){
+  rcon_cmd="$1"
+  logRcon "running - $rcon_cmd"
+  output=$(rcon-cli "$rcon_cmd")
+  logRcon "$output"
+}
+
+
+# wait for java process to be started
+while :
+do
+  if java_process_exists ; then
+    break
+  fi
+  sleep 0.1
+done
+
+CLIENTCONNECTIONS=0
+STATE=INIT
+
+while :
+do
+  case X$STATE in
+  XINIT)
+    # Server startup
+    if mc_server_listening ; then
+      logRcon "MCServer is listening, running startup"
+      if [[ "$RCON_CMDS_STARTUP" ]]; then
+        while read -r cmd; do
+          run_command "$cmd"
+        done <<< "$RCON_CMDS_STARTUP"
+      fi
+      if [[ -z "$RCON_CMDS_ON_CONNECT" ]] && [[ -z "$RCON_CMDS_ON_DISCONNECT" ]]; then
+        logRcon "No addition rcon commands are given, stopping rcon cmd service"
+        exit 0
+      fi
+      STATE=II
+    fi
+    ;;
+  XII)
+    # Main Loop looking for connections 
+    CURR_CLIENTCONNECTIONS=$(java_clients_connections)
+    if (( CURR_CLIENTCONNECTIONS > CLIENTCONNECTIONS )) && [[ "$RCON_CMDS_ON_CONNECT" ]]; then
+        logRcon "Clients have Connected, running connect cmds"
+        while read -r cmd; do
+          run_command "$cmd"
+        done <<< "$RCON_CMDS_ON_CONNECT"
+    elif (( CURR_CLIENTCONNECTIONS < CLIENTCONNECTIONS )) && [[ "$RCON_CMDS_ON_DISCONNECT" ]]; then
+        logRcon "Clients have Disconnected, running disconnect cmds"
+        while read -r cmd; do
+          run_command "$cmd"
+        done <<< "$RCON_CMDS_ON_DISCONNECT"
+    fi
+    CLIENTCONNECTIONS=$CURR_CLIENTCONNECTIONS
+    ;;
+  *)
+    logRcon "Error: invalid state: $STATE"
+    ;;
+  esac
+  sleep "$RCON_CMDS_PERIOD"
+done

scripts/start-configuration

@@ -8,6 +8,10 @@ IFS=$'\n\t'
 : "${EULA:=}"
 : "${PROXY:=}"
 : "${RCON_PASSWORD_FILE:=}"
+: "${RCON_CMDS_STARTUP:=}"
+: "${RCON_CMDS_ON_CONNECT:=}"
+: "${RCON_CMDS_ON_DISCONNECT:=}"
+: "${RCON_CMDS_PERIOD:=10}"
 
 shopt -s nullglob
 
@@ -124,6 +128,12 @@ if isTrue "${ENABLE_AUTOSTOP}"; then
   ${SCRIPTS:-/}start-autostop
 fi
 
+if [[ "$RCON_CMDS_STARTUP" ]] || [[ "$RCON_CMDS_ON_CONNECT" ]] || [[ "$RCON_CMDS_ON_DISCONNECT" ]]; then
+  log "Starting RCON commands"
+  # shellcheck source=start-rconcmds
+  ${SCRIPTS:-/}start-rconcmds
+fi
+
 if versionLessThan 1.7; then
   echo "
 MC_HEALTH_EXTRA_ARGS=(

scripts/start-rconcmds

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+# shellcheck source=start-utils
+. "${SCRIPTS:-/}start-utils"
+
+: "${RCON_CMDS_STARTUP:=}"
+: "${RCON_CMDS_ON_CONNECT:=}"
+: "${RCON_CMDS_ON_DISCONNECT:=}"
+: "${RCON_CMDS_PERIOD:=10}"
+: "${SERVER_PORT:=25565}"
+export RCON_CMDS_STARTUP
+export RCON_CMDS_ON_CONNECT
+export RCON_CMDS_ON_DISCONNECT
+export RCON_CMDS_PERIOD
+export SERVER_PORT
+
+log "Rcon cmds functionality enabled"
+
+isDebugging && set -x
+
+if ! [[ $RCON_CMDS_PERIOD =~ ^[0-9]+$ ]]; then
+  RCON_CMDS_PERIOD=10
+  export RCON_CMDS_PERIOD
+  log "Warning: RCON_CMDS_PERIOD is not numeric, set to 10 (seconds)"
+fi
+if [ "$RCON_CMDS_PERIOD" -eq "0" ] ; then
+  RCON_CMDS_PERIOD=10
+  export RCON_CMDS_PERIOD
+  log "Warning: RCON_CMDS_PERIOD must not be 0, set to 10 (seconds)"
+fi
+
+/rconcmds/rcon-cmds-daemon.sh &

scripts/start-utils

@@ -117,6 +117,10 @@ function logAutostopAction() {
   echo "[$(date -Iseconds)] [Autostop] $*"
 }
 
+function logRcon() {
+  echo "[Rcon loop] $*"
+}
+
 function normalizeMemSize() {
   local scale=1
   case ${1,,} in