Add /plugins mount for external bukkit plugins

Add TYPE=BUKKIT documentation

minecraft-server/Dockerfile

@@ -14,7 +14,8 @@ RUN useradd -M -s /bin/false --uid 1000 minecraft \
   && mkdir /data \
   && mkdir /config \
   && mkdir /mods \
-  && chown minecraft:minecraft /data /config /mods
+  && mkdir /plugins
+  && chown minecraft:minecraft /data /config /mods /plugins
 
 EXPOSE 25565
 
@@ -24,6 +25,7 @@ COPY start-minecraft.sh /start-minecraft
 VOLUME ["/data"]
 VOLUME ["/mods"]
 VOLUME ["/config"]
+VOLUME ["/plugins"]
 COPY server.properties /tmp/server.properties
 WORKDIR /data
 

minecraft-server/README.md

@@ -146,6 +146,57 @@ This works 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.
 
+## Running a Bukkit/Spigot server
+
+Enable Bukkit/Spigot server mode by adding a `-e TYPE=BUKKIT -e VERSION=1.8` or `-e TYPE=SPIGOT -e VERSION=1.8` to your command-line.
+
+The VERSION option should be set to 1.8, as this is the only version of CraftBukkit and Spigot currently
+available.  The latest build in this branch will be used.
+
+    $ docker run -d -v /path/on/host:/data \
+        -e TYPE=SPIGOT -e VERSION=1.8 \
+        -p 25565:25565 -e EULA=TRUE --name mc itzg/minecraft-server
+
+You can install Bukkit plugins in two ways.
+
+### Using the /data volume
+
+This is the easiest way if you are using a persistent `/data` mount.
+
+To do this, you will need to attach the container's `/data` directory
+(see "Attaching data directory to host filesystem”).
+Then, you can add plugins to the `/path/on/host/plugins` folder you chose. From the example above,
+the `/path/on/host` folder contents look like:
+
+```
+/path/on/host
+├── plugins
+│   └── ... INSTALL PLUGINS HERE ...
+├── ops.json
+├── server.properties
+├── whitelist.json
+└── ...
+```
+
+If you add plugins while the container is running, you'll need to restart it to pick those
+up:
+
+    docker stop mc
+    docker start mc
+
+### Using separate mounts
+
+This is the easiest way if you are using an ephemeral `/data` filesystem,
+or downloading a world with the `WORLD` option.
+
+There is one additional volume that can be mounted; `/plugins`.  
+Any files in this filesystem will be copied over to the main
+`/data/plugins` filesystem before starting Minecraft.
+
+This works well if you want to have a common set of plugins in a separate 
+location, but still have multiple worlds with different server requirements
+in either persistent volumes or a downloadable archive.
+
 ## Using Docker Compose
 
 Rather than type the server options below, the port mappings above, etc

minecraft-server/start-minecraft.sh

@@ -289,6 +289,11 @@ do
     cp -rf "$c" /data/config
   fi
 done
-
+if [ "$TYPE" = "SPIGOT" ]; then
+  echo Copying any Bukkit plugins over
+  if [ -d /plugins ]; then
+    cp -r /plugins /data
+  fi
+fi
 
 exec java $JVM_OPTS -jar $SERVER