Vagrant Working for the Manchester CoderDojo Minecraft Server Build

I've got a basic vagrant setup working for the Manchester CoderDojo Minecraft server build.  Instructions on the GitHub page.

Next task is to get the chunked responses working so that you can see the python output appear in the browser as the code is running.

Working on the Minecraft-Scratch Interface for the Rube Goldberg Machine

For the Rube Goldberg project at the CoderDojo I need a way to interact with Scratch from Python.  Here's my steps of how I went about it:

1. After reading around I realised that I'd have to run Scratch 1.4 and the Python interaction would come from scratchpy - https://github.com/pilliq/scratchpy
2. Installed scratch 1.4 on Windows
3. pip install scratchpy
4. Enabled Scratch remote sensing - http://wiki.scratch.mit.edu/wiki/Remote_Sensor_Connections#Enabling
5. Played with the interaction - http://youtu.be/YG99uam8pKA
6. Create new branch for scratch plugin git checkout -b scratch-plug
7. Check all tests pas
8. python setup.py test
9. Tests failed as wasn't on Rasp PI.  After some poking around I discovered that I'd installed the GPIO package on to my development virtual box environment, and so now the package was loading okay and the case that I had set up in the test file to spot the lack of GPIO wasn't working.  I deleted out the GPIO package and it all worked again...phew!
10. Making the scratch target -- use a broadcast of either "BLOCK-PRESENT" or "BLOCK-ABSENT"
11. Create a scratchplug.py module
12. Implemented the target code
13. Tested that it worked using a file source
14. Not quite sure how to make the unit tests work.  Will park that problem for now and come back to it later
15. Now to make the source method
16. The problem is that the scratch.receive() method blocks until it receives a broadcast, but the Rube Goldberg architecture needs to poll
17. The solution will be to use the multiprocessing module as shown in this answer on Stack Overflow - http://stackoverflow.com/questions/492519/timeout-on-a-python-function-call
18. Got a bit stuck coordinating the output with Queues since I didn't realise that multiprocessing had its own implementation of Queue -- you live and learn
19. Committed that on to the scratch-plug and pushed to GitHub
20. Made a quick demo of the Minecraft light going into scratch and scratch button turning on a light in Minecraft - https://www.youtube.com/watch?v=cpD-RegWybA

Python Minecraft CoderDojo -- Play Testers Sought

I've updated the sheets for the Manchester (UK) CoderDojo Python-Minecraft project.  I'm looking for play-testers.  If you are interested, take a look at this on the Minecraft Forum:

http://www.minecraftforum.net/topic/2427342-python-programming-sheets-for-coderdojo-play-testers-sought/

ScriptCraft Server Updated for Latest "classroom" Module

Walter Higgins from ScriptCraft has just added a "classroom" module to ScriptCraft. (Here's what changed on GitHub).  Here are the steps I followed to upgrade the Madlab Miners ScriptCraft server:

1. Log on to the server as the scriptcraft user
2. wget http://scriptcraftjs.org/download/2013-06-09/ScriptCraft.jar
3. Re-attach to the scriptcraft screen session  (screen -r)
4. Type "stop" at the server prompt, and wait for it to stop (takes several seconds to save the chunks from all the Multiverse worlds)
5. mv ~/ScriptCraft.jar ~/bukkit/plugins
6. Restart the server using the bash file: ./startserver.sh
7. Once the server is up login and check that you can turn on the classroom with: /js classroom.allowScripting(true)
8. Works like a charm!
   

Setting Up ScriptCraft

I've been looking at ScriptCraft as something for us to play with at the next MadLab CoderDojo.  Here are my notes on getting the server running...

(1) First I created a new "scriptcraft" user on the server
(2) I then installed Bukkit.  I'm running the "02110_1.5.2-R0.1" beta version of Bukkit so that the 1.5.2 Minecraft client works
(3) I set up a startserver.sh batch file to hold the commands to start things up
(4) I edited the server.properties file to bind Bukkit to port 25566.  There is the vanilla Minecraft server already running on the standard port 25565
(5) I changed to the plugins directory and pulled down the latest ScriptCraft.jar file


wget http://scriptcraftjs.org/download/2013-03-31/ScriptCraft.jar

(6) I then restarted the server and logged in with the Minecraft client, added my user to ops.txt,  typed

/js up().box('35:15', 4, 9, 1)

...and made myself a nice 2001: A Space Odyssey style monolith.

Minecraft 1.5.2 Server Upgrade

I've updated the Madlab Miners Minecraft server to version 1.5.2.  I followed the instructions from my previous post.

Minecraft 1.5.2 is Out

...here's the change log.  I think I'll be updating the Madlab Miners server on Saturday.

Minecraft and Minetest Update Permissions Without a Restart

Quick note to self about Minecraft and Minetest server admin tasks.

How to Update Minecraft White-List Without a Restart

This is especially needed to white-list players without shutting down the server:

1. Make the edits to the server white-list.txt
2. On the server as an op run "/whitelist reload"

More information can be found on the commands page on the Minecraft wiki.

How to Update the Minetest auth.txt Settings Without a Restart

Similar problem on Minetest: how to change the auth.txt setting on a running server without a restart:

1. The Minetest wiki page on privileges states that you should NOT edit the auth.txt file while the server is running
2. Instead us the "/grant <name> <privilege>" command to give a privilege to a player (you need the "privs" privilege to be able to do this
3. The running server will write out the update to the auth.txt file

Minecraft Server Update Time

It's time to update the minecraft server to version 1.5.  Here are the steps.

1. Log on to the server and stop the running minecraft
2. Rename the old server file:
   

   mv minecraft_server.jar minecraft_server.jar.old

3. Download the latest jar file:
   

   wget https://s3.amazonaws.com/MinecraftDownload/launcher/minecraft_server.jar

4. Restart the server
5. Once you are happy it is working you can remove the backed up server jar file

Minetest

Minetest looks very interesting as a Minecraft alternative.  Here's a very quick comparison.

I'm going to try and get a server up and running for the Madlab Miners session at the Coder Dojo this weekend.

Minecraft Running On Old Laptop

I've been setting up the Minecraft client on an old Dell Inspiron 1300 laptop running Windows XP. The basic installed failed complaining that I had a bad video card driver. The solution was to go into Control Panel, click Display, pick Settings, Advanced. Under that menu find Troubleshoot and turn down the hardware acceleration settings. Mine worked at just less than halfway turned on. In order to get the client to run without too much lag I had turn turn the render distance down and turn off other fancy graphics options.

Minecraft Mod Manager Website Wish

I seem to have become the Minecraft system support person for lots of son #1's friends. The trouble is that they all want mods installed and while not that difficult, you need to be able to unpack JAR files in order to do that. This is well beyond the technical grasp of most Minecraft parents it seems. What I really want is a web site where you can just click a few buttons and it will install the mods. I'm going to see if I can contact the person who writes MineSwitcher to use that as a starting point.

Setting Up A Minecraft Server

#1 and #2 sons are both addicted to Minecraft. In our "Dad and son techie evening" this week #1 son said that he wanted to set up a Minecraft server. It was actually very easy.

1. Follow the instructions from the Minecraft Wiki to get the Java files on to the server
2. I had to reduce the memory footprint as I'm installing it on the Rimuhosting VPS server that is quite restricted on RAM. I went for starting with 500 megs and maximum of 800 megs
3. Set up a white list file with the users we want to allow
4. Kick off the server: java -Xms500M -Xmx800M -jar minecraft_server.jar nogui

For now I just kept the server running in a screen session on the server. I do have a shopping list of things to tidy up:

• Set it up properly to start at boot time following the Debian init.d approach
• Set up logrotate to manage the log file
• I really must set up iptables or equivalent to give me a suitable firewall

Minecraft Mod Manager

Son #1 has got hugely into Minecraft recently. As a result son #2 is now interested in it also, but that's a different story. I've been roped in as the tech support to install all the "mods". Installing mods involves unpacking and repacking the contents of the minecraft.jar file and moving resources about in your minecraft folder. This is too tricky for a nine-year-old to do reliably at the moment. I've started writing a python script to automate the process. I had a quick goolge to see if I could find someone solving this problem already but didn't find anything.