For #19: added PVP env var options

* also adding a marker env var for MCCY to reference

minecraft-server/Dockerfile

@@ -25,9 +25,10 @@ WORKDIR /data
 
 CMD [ "/start" ]
 
-ENV UID 1000
+# Special marker ENV used by MCCY management tool
+ENV MC_IMAGE=YES
+
+ENV UID=1000
 ENV MOTD A Minecraft Server Powered by Docker
-ENV LEVEL world
 ENV JVM_OPTS -Xmx1024M -Xms1024M
-ENV TYPE VANILLA
-ENV VERSION LATEST
+ENV TYPE=VANILLA VERSION=LATEST LEVEL=world PVP=true

minecraft-server/README.md

@@ -170,6 +170,13 @@ docker run -d -e 'MOTD=My Server' ...
 If you leave it off, the last used or default message will be used. _The example shows how to specify a server
 message of the day that contains spaces by putting quotes around the whole thing._
 
+### PVP Mode
+
+By default servers are created with player-vs-player (PVP) mode enabled. You can disable this with the `PVP`
+environment variable set to `false`, such as
+
+    docker run -d -e PVP=false ...
+
 ### World Save Name
 
 You can either switch between world saves or run multiple containers with different saves by using the `LEVEL` option,

minecraft-server/start-minecraft.sh

@@ -84,6 +84,10 @@ if [ ! -e server.properties ]; then
     sed -i "/level-seed\s*=/ c level-seed=$SEED" /data/server.properties
   fi
 
+  if [ -n "$PVP" ]; then
+    sed -i "/pvp\s*=/ c pvp=$PVP" /data/server.properties
+  fi
+
   if [ -n "$MODE" ]; then
     case ${MODE,,?} in
       0|1|2|3)