Overall the instructions on code.google.com are really good, so this is just a dump to remind me of the Ubuntu specific stuff I did on a pristine Ubuntu installation…


sudo apt-get install sun-java6-jdk
sudo apt-get install ruby-full rubygems


This installs only rubygems 1.3.1 but appengine needs 1.3.5.

ERROR: Error installing google-appengine:
bundler requires RubyGems version >= 1.3.5


sudo gem install rubygems-update
sudo /var/lib/gems/1.8/bin/update_rubygems
sudo gem install google-appengine


Et voilà! Ten minutes later I have a running hello world in the cloud

The usual problem: you want to kill a process.

$ ps aux | grep randomprocessname
psycho 20429 0.0 0.0 11824 1580 pts/7 S+ 12:00 0:00 /bin/bash ./randomprocessname
psycho 20528 0.0 0.0 4188 740 pts/17 R+ 12:00 0:00 grep randomprocessname
$ pkill -9 randomprocessname
WTF? Kill that sucker!
$ pkill -9 randomprocessname
No typo... Am I crazy?
$ pgrep randomprocessname
What's wrong?
$ pgrep randomprocessna
20429
$ pkill -9 randomprocessna

For some arcane reason pgrep/pkill matches only the first 15 characters.

Quite some time has passed since the last time I wrote something on this blog, mostly because I did little non-work related worth mentioning.

But last week I helped Damon to finally support JRuby on his Android Scripting Environment (ASE).

• Downloaded JRuby sources (jruby-1.2.0RC1) from http://www.jruby.org/download.
• Patched the build.xml to not include doc/index.html from dynalang.jar otherwise dx will complain about an HTML page in the ruby-complete.jar.
  
  

  $ diff -r jruby-1.2.0RC1 jruby-1.2.0RC1.patched/
  Only in jruby-1.2.0RC1.patched/: build
  diff -r jruby-1.2.0RC1/build.xml jruby-1.2.0RC1.patched/build.xml
  42c42
  <
  ---
  >
  238c238,240
  <         <zipfileset src="${build.lib.dir}/dynalang-0.3.jar"/>
  ---
  >         <zipfileset src="${build.lib.dir}/dynalang-0.3.jar">
  >           <exclude name="**/doc/index.html"/>
  >         </zipfileset>
  268c270,272
  <         <zipfileset src="${build.lib.dir}/dynalang-0.3.jar"/>
  ---
  >         <zipfileset src="${build.lib.dir}/dynalang-0.3.jar">
  >           <exclude name="**/doc/index.html"/>
  >         </zipfileset>
  387c391,393
  <         <zipfileset src="${build.lib.dir}/dynalang-0.3.jar"/>
  ---
  >         <zipfileset src="${build.lib.dir}/dynalang-0.3.jar">
  >           <exclude name="**/doc/index.html"/>
  >         </zipfileset>

• Downloaded the JSON sources from http://rubyforge.org/frs/?group_id=953 and put them in lib/ruby/1.8/json/
• Copied android.rb to lib/ruby/1.8/.
• Built jar-complete (ant jar-complete) and added jruby-complete.jar to eclipse project.
• Connected the bits and pieces in com.google.ase.interpreter.jruby

But beware! The new ASE apk is HUGE (4.6M) and JRuby is fairly slow. But it works

Last week I added the 1gb data plan to my Simyo contract to use the SIM with my Christmas G1. I tried a few configurations I found online for simyo but they did not work for me. After some frustration I tried an eplus configuration and this one finally worked for me:


Name: does not matter
APN: internet.eplus.de
Proxy: <empty>
Port: <empty>
Username: eplus
Password: <empty>
Server: <empty>
MMSC: <empty>
MMS proxy: <empty>
MMC: 262
MNC: 03
APN type: <empty>


Update:

The recommended configuration is:


Name: does not matter
APN: internet.eplus.de
Proxy: <empty>
Port: <empty>
Username: simyo
Password: simyo
Server: <empty>
MMSC: <empty>
MMS proxy: <empty>
MMC: 262
MNC: 03
APN type: <empty>


After the initial success with the eplus configuration, I had some problems with it, too. But I guess these errors were internal eplus network hiccups because they were gone without me changing anything and now both configs work.

A few days ago I finally upgraded my (== my employer’s) Macbook Pro from Tiger to Leopard. Everything worked flawless except for one crazy problem: I could not use to tab key the way I used to in forms. My usual routine of quickly entering username, tab, password, tab, hit return did not work anymore. I searched through the Firefox settings but couldn’t find the “Drive psycho crazy”-option.

But thanks to the omniscient internet I found a solution. At the bottom of the “Keyboard & Mouse” preferences page is a setting which allows you to navigate only between text boxes or between all controls. I don’t know who came up with the great idea that the default should be “text boxes and lists only”, but I guess the mighty Steve knows what he is doing.

Last week I cross-compiled miniruby to Android (more details on that adventure later). I asked some time ago about JRuby on Android and it seems like Charles Nutter finally managed to run JRuby on Android.

# cat test.rb
require 'java'
import java.lang.System

class Ruboto
  def greet(who)
    puts "Hello, #{who}!"
  end
end

name = System.get_property('java.runtime.name')
Ruboto.new.greet(name)

# dalvikvm -classpath ruboto.jar org.jruby.Main -X-C test.rb
Hello, Android Runtime!

This leaves only one question: where can I get ruboto.jar to start playing around with it

Seems like nowadays I only write blog posts in response to other blog articles… But I hope this is better than not writing at all. Ted Neward asks if code reviews do actually work because evidence suggests, that the scientific review process does not. Read the rest of this entry »

I stumbled over a great essay on pair-programming (via James Shore).

Rod Hilton explains it much better than I could ever do, why you should Pair-Program. But I haven’t heard about the “ping-pong pairing”:

When doing Test-Driven Development, one of the things we do is called “ping-pong pairing”. So the other developer will write a test, then make it compile but fail. Then he passes the keyboard to me. I implement the feature just enough to make the test pass, then I write another failing test and pass it back.

I have to try this on Monday…

Sometimes you want to reset a database to its virgin state, without actually deleting and re-creating the whole database (perhaps because your user doesn’t have the right to create a database). There are a lot of links out there that give you a quick answer on how to drop all tables from a database in a single-line shell script. Some examples:

• http://www.thingy-ma-jig.co.uk/blog/10-10-2006/mysql-drop-all-tables
• http://www.cyberciti.biz/faq/how-do-i-empty-mysql-database/
• http://knaddison.com/technology/mysql-drop-all-tables-database-using-single-command-line-command

However this does not work if there are foreign key constraints between the tables (because the tables constraining others need to be deleted first). Here’s the advanced version that solves this problem:

#!/bin/bash
USERNAME=myUser
PASSWORD=myPassword
HOSTNAME=dbHost
DATABASE=mydb
while (true) ; do
    TABLES=`mysql -h $HOSTNAME -u $USERNAME -D $DATABASE --password=$PASSWORD 
                  --batch -e "show tables" | grep -v Tables_in`
    if [ -z $TABLES ] ; then break; fi
    for i in $TABLES ; do
        mysql -h $HOSTNAME -u $USERNAME -D $DATABASE --password=$PASSWORD  -e "drop table $i"
    done
done

I agree this is not nice because it’s a brute force approach – but hey, it works! And resetting a database is most probably not a performance-critical task anyway.

The date for Euruoko 2009 was announced. The location was announced a few months ago but the planned date was Q1 2009. This year’s Euruko in Prague was great and I will try hard to come to Barcelona, too.