Hendrik Volkmer - Home

Running an Ioke web application on Google App Engine using Ikanserve

2009-04-08T20:01:00Z

I like to play around with interesting technologies. So what’s on the table today?

Google App Engine allows you to run Java applications since a few days. But as no one writes web apps in Java anymore you could either use JRuby on App Engine or try out another fine language on the JVM. (That’s why I think the JVM kicks ass and I still like it after several years of programming mostly in Ruby: It’s a great plattform to run things… not just Java programms but any language that’s on the JVM. And there will be more…). But I digress…

So, let’s get into it:

0. Create a temp dir to play in


$ mkdir appgarage
$ cd appgarage

1. Get an App Engine Account

2. Sign Up for the Java App Engine Account – According to TechCrunch the first 10k developers get an account. So hurry up!

3. Get ioke E

You need git and java 1.6 to do that.


$ git clone git://github.com/olabini/ioke.git
$ cd ioke
$ ant
$ cd ..

3. Get Ikanserve


$ git clone git://github.com/olabini/ikanserve.git
$ cd ikanserve
$ ant
$ cd ..

4. Get the Java App Engine SDK


$ unzip appengine-java-sdk-1.2.0.zip
$ cd appengine-java-sdk-1.2.0
$ cd ..

Optional: Try out the app engine demos and/or the ikanserve demo locally

5. Merge Ikanserve with appengine


$ mkdir myikanserveengine
$ cd myikanserveengine
$ unzip ../ikanserve/jetty/webapps/root.war 
$ cp ../ioke/lib/ioke.jar lib/
$ cat > WEB-INF/appengine-web.xml 
<appengine-web-app xmlns="http://appengine.google.com/ns/1.90">
  <application>myikanserveengine</application>
  <version>1</version>
^D
$ cd ..
</appengine-web-app>

A few explanations: You need to unzip the war file because app engine only takes war dirs not files. And you you need to copy the ioke jar because the ioke version supplied with ikanserve (at this point in time) doesn’t work with appengine. The current Ioke version does work.

6. Deploy your application

Go to the App Engine Admin Interface log in and create an application with the same name you choose in your appengine-web.xml file (Here it was “myikanserveengine”).


$ cd appengine-java-sdk-1.2.0
$ bin/appcfg.sh -e yourgoogleaccountemail@yourdomain.com update ../myikanserveengine

Done.

Goto http://myikanserveengine.appspot.com and enjoy your first Ioke web application in the cloud. Try URLs like foo or xxx to see some extra funky stuff ;-)

Predictably Irrational

2009-02-01T14:02:00Z

I just finished reading Predictably Irrational by Dan Ariely It’s a fantastic book, very well written and super interesting. I highly recommend reading it to get some insight in irrational human behaviours.

More about the book and behavioural economics on the website predicatbly Irrational

Deploying a Rails application on OpenSolaris with passenger aka modrails

2009-01-29T07:05:00Z

Two technologies I wanted to play around with for some time are OpenSolaris and passenger. OpenSolaris because of ZFS, Zones, SMF and the latest addition IPS and passenger because it seems to be the new default Rails deployment model and is really easy to configure.

So I deceided to combine those to and get started. Here’s what I did. Maybe it’s useful for someone who’s trying to do the same.

I grabbed the OpenSolaris 2008.11 Virtualbox image from virtualboximages.com and booted it in VirtualBox.

I wanted to make sure to have the latest updates so I updated the image (all commands are executed as root):


# pfexec pkg image-update

A reboot later I installed the necessary parts for a Rails environment:


# pfexec pkg install SUNWruby18
# pfexec pkg install gcc-dev

SUNWruby18 installes ruby 1.8.6p287 which is exactly what I needed. The mysql installation was a bit harder:


# pfexec pkg install SUNWmysql5
# /usr/mysql/5.0/bin/mysql_db_install
# chown -R mysql:mysql /var/mysql/5.0/data

I needed to manually chown the data dir. Otherwise mysql wouldn’t start. You can confirm that your mysql is running via:


# svcs -l mysql

The logfile gives further information if something goes wrong. To access mysql try:


# /usr/mysql/5.0/bin/mysql

The “5.0” in the path is important because there’s also a mysql version 4 installed. This will be of interest when installing the mysql ruby gem. The command to correctly install the gem is:


# pfexec gem install mysql -- --with-mysql-lib=/usr/mysql/5.0/lib/mysql --with-mysql-include=/usr/mysql/5.0/include

Thanks to Amanda Waite for this hint. The next installation step is Apache:


# pfexec pkg install SUNWapach22

Make sure it starts via svcadm:


# svcadm start apache22

Check that it runs:


# svcs -l apache22

(or just type http://localhost in your browser) I needed memcached, so I installed it:


# pfexec pkg install SUNWmemcached

It didn’t start right away, though. There are some changes you have to apply to run memcached in solaris


# svccfg
svc:> select memcached
svc:/application/database/memcached> setprop memcached/options=("-u" "nobody" "-m" "2048")
svc:/application/database/memcached> quit
# svcadm refresh memcached

Of course we need rails:


pfexec gem install rails

The current stable version of passenger doesn’t support Solaris but the egde version does. So I downloaded the passenger edge Version off github.

It didn’t compile right away. There are some compiler flags that aren’t supported in Solaris so I used these changes to make passenger compile.

Commandwise this looked like this: I unpacked the tarball into /opt/passenger and then did a


# cd /opt/passenger
# vi lib/passenger/platform_info.rb # see above
# bin/passenger-install-apache2-module
# chown -R webservd /opt/passenger

Add the mentioned config snippet to /etc/apache2/httpd.conf and restart apache


# svcadmin restart apache2

Now were all set to create a new rails app. I created a seperate ZFS partition to serve the apps. Just because it’s so easy to do with ZFS and it gives you more control on how much space is used by your apps etc.


# zfs create rpool/apps

Now it’s time for the demo app:


# cd /rpool/apps
# rails demo
# chown -R webservd demo

I added the DocumentRoot of the app to the apacheconfig (“DocumentRoot /rpool/apps/demo/public”) and restarted apache again (svcadm restart apache2 – you know the drill by now).

And that’s it. A http://localhost gave me the demo welcome page. Nice.

Later I wanted do deploy a rails app via capistrano so I needed git. There isn’t a IPS package for git yet, so I decided to take the standard compile route. I downloaded git and compiled it like this:


# ./configure --prefix=/opt/git
# make install
# ln -s /opt/git/bin/git /usr/bin/git

I used the symlink because capistrano wasn’t able to find git otherwise – setting scm_command didn’t work.

If anyone tries this recipe and it works or it doesn’t work… just let me know. Have fun with OpenSolaris. It’s worth checking out.

Präsentationen und die lieben Bullet Points

2008-11-22T08:22:00Z

Wer kennt das nicht: Man sieht oder hört etwas, was man vorher noch nie gesehen oder gehört hat und danach kann man es nicht mehr ignorieren. Sei es ein kleiner Kratzer im Autolack, ein bestimmtes Wort was manche Leute besonders oft sagen, oder – worum es hier nun gehen soll – Aufzählungspunkte in Präsentationen. Natürlich habe ich die “Bullet points” schon immer gesehen, aber seit ich presentationzen in meinem RSS-Reader habe, nehme ich die Folien von Präsentationen anders wahr. Die “Bullet points” werden fast zu “bullets”, die vom Beamer abgefeuert meinen Kopf treffen und den ganzen Inhalt töten. – OK, man muss nicht übertreiben, aber ich sehe diese Viecher nun deutlich intensiver.

Egal ob bei firmeninternen Präsentationen, bei Vorträgen auf Konferenzen, User-Group treffen oder bei Vortägen, die man im Internet so sehen kann (z.B. bei InfoQ, oder TED ). Ich frage mich nun immer: Was machen diese Punkte denn da? Welche Information wollen sie mir vermitteln? Wäre es nicht sinnvoller, einfach die Worte auf die Folie zu schreiben ohne die Punkte? Vielleicht ein Bild dazu?

Schlimmer als die Punkte an sich sind aber zu volle Folien. Früher habe ich nur gedacht “oh… da ist aber viel drauf”. Nun erschlägt mich die Vielzahl an Informationen fast. In Seth Godins Really bad powerpoint steht: Niemals mehr als sieben Wörter pro Folie. NIE. Mehr als ein Satz (bei Zitaten auch mal zwei oder drei) sollte wirklich nicht auf einer Folie stehen. Die Zuschauer sollten bei einem Vortrag zuhören und nicht die Folien lesen müssen.

Wenn ich mich an mein Studium erinnere: Da gab es teilweise Folien mit 7 Sätzen oder 70 Wörtern… Als ich mir vor drei Wochen beim 25 Jährigen Jubiläum des Studiengangs Wirtschaftsinformatik an der BA-Stuttgart die Vortäge anhörte, wurde ich wieder daran erinnert.

Als Denkanstoß kann ich nur das Buch von Presentation Zen von Garr Reynolds empfehlen (oder wer es auf deutsch lieber liest: ZEN oder die Kunst der Präsentation ) – Das ganze gibt’s auch im Internet kostenlos und aktuell (aber nicht so schön verpackt) als Blog: presentationzen

Really Adobe? Really?

2008-10-09T13:39:00Z

I just encountered this problem and I can totally understand this blog post: If Adobe were a man, i would punch him

Let me remind you: This is a product that costs about 1K EUR and it’s the year 2008.

So Dear Adobe : Please fix your products!

Some thoughts

2008-10-01T21:12:00Z

... not my own… well actually most of them are.

”

helping other people helps me
having guts always works out for me
thinking life will be better in the future is stupid. i have to live now
starting a charity is surprisingly easy
being not truthful works against me
everyting i do always comes back to me
assuming is stifling
drugs feel great in the beginning and become a drag later on
over time i get used to everything and start taking for granted
money does not make me happy
travelling alone is helpful for a new perspective on life
keeping a diary supports personal development
trying to look good limits my life
material luxuries are best enjoyed in small doses
worrying solves nothing
complaining is silly. either act or forget
actually doing the things I set out to do increases my overall level of satisfaction
everybody thinks they are right
low expectations are a good strategy
whatever I want to explore professionally, its best to try it out for myself first
everybody who is honest is interesting”

by Stefan Sagmeister

via [ Stefan Sagmeister: Things I have learned in my life so far ]

Longtime value of tests

2008-09-09T06:16:00Z

I wrote back in January 2007 that I’m test infected and that is still true. But sometimes, as with all things, I forget about the value of tests – at least in some contexts and then I find the value again.

Last week I attended Jay Fields’ talk about functional testing lessons learned and he really gave some interesting insights on the value of tests. Do you need tests for everything? Certainly not. 100% code coverage? Bad idea. Do you always need tests? Maybe. As always: it depends. What Jay Fields said was: If you intend to use the code again and want to change it sometime, you better have tests.

And if you think about it: That’s almost always the case. The last weekend I ported two small applications to new releases of some libraries (one was a merb app, the other one was a Rails app + some internal imedo libraries). Those two applications where nothing like “business critical” – they were indeed some kind of testing/prototyping application to try some things out. So did I write tests back when I wrote them? No. Because I didn’t see value in writing tests, when I wrote these application. It just seemed like some additional work and well, those apps where so simple and just used to try some stuff: Why do you need tests for them?

In retrospective I think rather different about those two apps. You don’t even need to change your own code to get vaue out ouf tests. What if you upgrade to some newer version of a library or some external service changed their API? How do you notice that those changed? Maybe they haven’t. Maybe the API is still the same, but its behavoir is different – This shouldn’t be the case, but who knows? How do you know that those changes don’t brake your application in the weirdest ways you can think of. Maybe it’s some strange edge case that almost never happens but it just happens to be the case that you excercise this edge case.

Or there was a bug in the library which you thought of as a feature (as in “every behaviour of a library – intended or not – is a feature”...) used it and now it got “fixed” which for you means: it breaks your app. And trust me, it’s very frustrating to hunt down bugs in your application which then turn out to be caused by changes in external libraries/services. Without tests you have no idea, if it’s your fault or “theirs”.

How do you know what’s going on under the hood, if you don’t have tests? This doesn’t meant that you should write tests for the external libraries (although that sometimes is indeed a good idea), it means you should be sure which beavhiour is caused by your app and which isn’t.

This, to me, showed again the value of tests. And that for the most part it manifests itself later in the project, not necessarily when you’re writing them. I don’t talk about TDD (or BDD) here. That’s another thing (which you can see value in). It’s the value of tests in the long term. That’s why “test code is as important as application code” (to quote Jay Fields again).

So there’s absolutely now excuse to write no tests for valuable code. Be it backend code that uses databases, external services, your own business logic, or JavaScript based frontend code. If the code is of value to the user, you better have tests for it.

Java like experiences with merb

2008-09-09T06:01:00Z

Java? merb? What do they have in common? They are both multithreaded, fast, modular? You can choose which ORM, templating and JavaScript and testing framework you want to use?

With all these things being true, they have another thing in common: It can be very frustrating to develop a web app using these technologies.

I played around with merb at the beginning of the year just because it was something new and I like new things. I used something like 0.3.0 which as the version number suggests is an early development release. Things are supposed to change. And they have. merb was splittet into merb-core and merb-more and lots of other gems. Which in itself is a good idea but made it real hard to figure out what you really need.

Engouraged by the infos I got in the BoF session about merb by Yehuda Katz at RailsConf Europe, I wanted to play around with some new merb features.

On Saturaday I “ported” a very small (as in “the standard blog” app) merb 0.3.0 app to the current 0.9.5. And by “ported” I really mean: I’ve thrown the old implementation away and rewrote it from scratch – because after an hour or so of hunting errors and trying to find missing gems that I needed, I figured it would be easier to start with a new 0.9.5 app.

It’s a little bit ironic that the merb guys want to create a public API that doesn’t change often and yet it changed very often until now. You can’t really blame them – there is no official release yet – it’s a development version – but it makes playing around with this kind of thing really hard. I almost was at the point where I said “F’ it, i’ll use Rails and be happy with it” – which would have missed the point of playing around with merb.

To play with merb you have to read the code. There is documentation which is ok on some parts and missing on other but there are no useful tutorials or blog post. Ok, there are… but you have no idea which version of merb they are about so they’re pretty much useless: If you don’t use the exact version of merb the tutorial was written for it won’t work. – That’s a general problem with tutorials/blog posts for new technologies (I experienced the same with some rspec posts). So please, if you write a post or tutorial, mention which version of the tools you’re using.

So to summarize what do I like and don’t like about merb:

I like

the modular architechture (construction kit: pic what you need), merb-slices, etc.
that it is small and thus a good fit for focussed services
that it orm, js library, rendering framework agnostic
the idea of a public api that doesn’t change often
that there’s no real magic inside the code
that it’s rack based

I don’t like

the naming of the gems. It’s merb_activerecord but merb-assets. Why is it ”-” one time and ”_” the other time. If there’s some kind of logic behind that I was not smart enough to figure it out.
the merb-more gems sometimes just don’t work. e.g. form_for doesn’t work for me in 0.9.5 – and there are no specs/tests for it! Or at least I didn’t find them.
that it is hard to get started with, especially if you’re a spoiled Rails child. There should be a generator “merb-gen app—rails-like” which should hook you up with alle the things that rails has (and merb has as well if you choose the according orm, js, helper gems, etc.)
that things like pagination are quite hard (there’s merb_paginate + will_paginate and it works) – This isn’t really a merb problem and more a problem of how some rails plugins are too rails focussed – hopefully this will change when there are more Ruby web frameworks out there

“So you just wanted to write a rant and say the J-Word, Hendrik?” – Not really. I think merb is a great framework but, as every piece of software has some flaws, all of them can easily be fixed and let’s see what merb 1.0 will bring us. If you want to try out merb I recommend waiting until 1.0 (which is due in about a month) – or take the latest checkout from github where maybe everything is ok.

And if you use merb for something in production and don’t have tests (which is a bad idea in the first place), write them before you even think about upgrading to a newer version. This experience has once again shown the value of tests for me.

RailsConf Europe quotes

2008-09-05T05:40:00Z

There were a lot of cool presentations at RailsConf Europe this year. I’ll write some summaries later.

For now, here are some quotes I really liked:

“Java is to Javascript what car is to carpet” – at BoF “Xing on Rails”

“Using tables to store objects is like driving your car home and then disassembling it to put it in the garage. It can be assembled again in the morning, but one eventually asks whether this is the most efficient way to park a car.” – Esther Dyson (was quoted in the Maglev BoF)

Hug a developer

2008-08-29T05:41:00Z

via [ Marcel ] via [ juixie hug a developer ]

And indeed: It’s funny because it’s so true.

Umkleidekabinen-Hack in Kaufhäusern

2008-08-12T05:10:00Z

Ich habe eben mal wieder in Interview mit Bruce Schneier gehört und darin hat er zum wiederholten Male erwähnt, dass man Sicherheit oder ein Interesse an Sicherheit nicht lernen kann, sondern damit geboren wird. Ich glaube, ich habe das Interesse daran auch mitbekommen. Wenn ich unterwegs bin und irgendwelche Sicherheitsmaßnahmen sehe, denke ich unweigerlich darüber nach, wo Lücken und Probleme sind.

Vor kurzem war ich z.B. Kleidung einkaufen. Genauer gesagt, war ich nur dabei, als andere eingekauft haben. In den Ankleidekabinen werden ja seit einiger Zeit bei manchen Geschäften so “Teile-Anzahl-Anzeiger” verteilt, wenn man in die Kabine möchte. Ich nehme stark an, dass das dazu da ist, um zu kontrollieren, ob man genau so viele Teile wieder mit raus bringt, wie man mit hin genommen hat und nichts einfach so unter der eigenen Kleidung anzieht.

Das System funktioniert auch ganz gut, wenn das schön kontrolliert wird. (Was meistens auch passiert). Manche Geschäfte haben nun aber keine Marke mit “0” und da meine ich nun eine Lücke im System ausgemacht zu haben: Wenn man keine Marke bekommt, wenn man nichts mit reinnimmt, woher wollen die dann beim rausgehen wissen, ob ich schon am Anfang nichts dabei hatte?

Ein Angriff sähe dann beispielsweise so aus (das geht natürlich nur, wenn es realativ voll ist und die Person, die die Marken verteilt sich nicht zusätzlich merkt, wie viele Teile ich mit hatte):

Ich nehme z.B. 2 Kleidungsstücke mit rein und erhalte eine Marke mit einer “2” drauf. Dann gehe ich in die Kabine und ziehe die Kleidungsstücke unter meine Kleidung an. Beim Rausgehen, zeige ich natürlich die “2”-er Marke nicht und sage auf ggf. Nachfrage, dass ich nichts dabei hatte (man braucht natürlich hier einen Komplizen, der wirklich ein Stück wieder mit raus nimmt). Gäbe es eine Marke mit “0” müsste jeder der die Kabinen betritt eine Marke am Ende abgeben.

DHL vs. UPS

2008-08-10T16:48:00Z

I recently ordered something over the Internet which by default gets shipped with DHL in Germany. I hadn’t had much problems with shipping via DHL, they actually do have a tracking system now (I think UPS had that about 10 years earlier). So let me describe what happened and then describe how UPS handled a similar event.

The package was shipped from its source about 400km from its destination on July, 24th and the tracking system showed that it was on its way to Berlin and should have been there on July, 28th. But then I saw the message “Receipient unknown” in the tracking system. I was sure that I supplied the correct adress when I ordered and confirmed that. It was indeed the correct address.

It only showed the adress but not the full receipient name. The adress is correct, by the way. That’s the office building I wanted the package to be delivered to. So I called their customer support and asked, what went wrong. They couldn’t tell me. In fact, they said they cannot access more address information than I was seeing on the web page and that the package would be sent back. What? Are you kidding me?

So I mailed the company that I ordered the product from. They said they talked to DHL and they would change the address and redeliver it, without sending it back.

Which didn’t work. A few days later the package arrived back at the sender and they had do resend it. How stupid of DHL was that?

They finally managed to deliver the package… at August, 5th. Or so I thought, after reading this:

but it took them two days after it arrived in Berlin in their central warehouse. The message on the tracking system said something like that:

Which means “due to vacation, public holidays or company holidays the package will be stored in the warehouse.”. It was delivered the next day which was August, 6th. As it turned out there wasn’t enough space on the truck the day before. WTF?

Ok. Now a similar story with a UPS package delivery. There was also a problem with the address. This time I messed up and forgot to add the company name (I think that was the same problem with the DHL delivery…). So I got an E-Mail from UPS, telling me that they weren’t able to deliver the package and that I should call their customer support. Which I did. They changed the address and delivered the package the next day. Easy. That’s how it’s supposed to work.

Let’s assume the problem was indeed the missing company name and they had no idea at which company the receipient “Hendrik Volkmer” would work. They could have called the sender and ask if they have additional information. Either when they were standing in the lobby of the building or second best, when they returned to the local warehouse. Or they could have asked the receptionist in the office building to call the secretary of the biggest company in the building (which would have failed) and then the second biggest (which would have succeeded). Or they could have provided a better web tracking system which would show the complete address, so that I could have seen a problem with the address and provide them with the correct information. First I thought that not showing the complete address is some kind of privacy protection thing. But that cannot be true, as you can see in the screenshots: At different times the full address details will be shown. Also: After entring a 20 digit tracking number and a zip code I should be authorized to see the details.

I can hardly believe that sending the package back was the cheapest option for them. And even if it was… it was the worst option for the customer.

Do you like ?

2008-08-07T16:31:00Z

And with  I might mean Apple or the fruit apple.

Ok. This entry is totally useless... I just wanted to use the  sign ;-) - Does that "" even look like an Apple on windows machines? Is it a UTF-8 character?

Update: Apparently it's the unicode character 63743 in the UTF-8 private space. And it depends on the font if it really gets displayed as "the Apple apple". Interesting.

Falling asleep mindfully

2008-08-06T06:25:00Z

When I was going to sleep yesterday I realized that I pictured my thoughts and wondered if I can consciously realize the moment I fall asleep. There weren't many thoughts. It was like a big black void and some "thoughts" where flying around. Then they started to disappear, fading out or just going away. Then I thought: "I'm.... going... to fall asleep.... now". Then I was asleep. I think it's the second time that had this experience. It's quite intersting. Did this ever happen to you?

Helmlos

2008-06-17T10:16:00Z

Ich fahre relativ viel Fahrrad hier in Berlin und mir ist aufgefallen, dass sehr wenige Leute Helme tragen. Der Kopf scheint wohl nicht von vielen als schützenswertes Körperteil angesehen zu werden.

Heute morgen sah ich dann gleich zwei mal eine sehr skurrile Kombination. Einmal Mutter (ohne Helm) mit Kind (mit Helm) und einmal Vater (ohne Helm) mit Kind (mit Helm) – die Kinder jeweils im Kindersitz auf dem Gepäckträger.

Ich fragte mich dann, wie die Eltern ihren Kindern erklären, warum die Kinder Helme tragen müssen, Erwachsene aber nicht…

“Wenn du älter wirst, wird dein Kopf ganz hart und dann braucht man keinen Helm mehr.”

“Mami zieht keinen Helm auf, weil das doof aussieht, aber dir steht das echt gut.”

“Ein Helm ist wichtig, damit man bei einem Sturz nicht verletzt wird. Ich möchte nicht, dass du verletzt wirst. Mir ist es aber egal, wenn ich selbst verletzt werde.”

Das hab ich mir alles nur ausgedacht. Ich hab echt keine Ahnung, was die Leute ihren Kindern erzählen. Ich war kurz davor den einen Herren zu fragen… dachte aber dann: “Man muss die Leute ja nicht noch zusätzlich vor ihren Kindern blamieren…”