So, finally everything is prep’ed: flights booked, accommodation confirmed, host office organized and cat fed. Tomorrow, very early in the morning, off we go to Oslo to live and work there for one week

It’s just a short period of time but we’ll try to get the most out off it. We got in contact with the local ruby user group, starting off with a couple of beers on sunday and hopefully exchanging some great wisdom. Maybe we can also initiate a speaker exchange with the berlin ruby user group.

Thanks to shortcut who have been kind enough to let us stay at their office for the week, we are mighty excited to get a glimpse on their work culture. And in the evenings and weekends we will surely check out the vicinity of Oslo.

I’m sure this will be cool work holidays If anyone in Oslo wants to meet us just send an email. We’ll also be posting some photos once we’re there.

Wir sind gerade mit einem neuen Projekt gestartet - alles richtig “nach Lehrbuch”: kurze Iterationen, Iteration Planning zusammen mit dem Kunden, Behavior Driven Design, User Stories, automatisierte acceptance Tests - all die schönen Dinge die man in so einem modernen agilen Softwareprojekt haben will.

Während der Planung der ersten Iteration haben wir zusammen mit dem Kunden User Stories geschrieben, um sie anschließend direkt in den RSpec Story Runner zu werfen, also As a User I want to upload my photo So that everyone can see my smiley face. Da unsere Kunden deutsch sprechen war das Meeting und dementsprechend auch die Stories auf deutsch, also Als Benutzer will ich mein Foto hochladen können damit alle mein tolles Grinsegesicht sehen können. Damit der Story Runner damit umgehen konnte mussten wir ihm eine neue Sprache beibringen. So geht’s:

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We have just released a new rails plugin called workling_mailer. This plugin provides a module which - when included into an ActionMailer subclass - pushes all emails that would normally be delivered synchronously into a queue for asynchronous processing. For queuing it relies on the workling plugin which can use for example twitter’s starling as a queue server.

We use this on autoki which sends a lot of email (thanks to our social feed plugin ).

Recently we got errors from the mailserver complaining about too many concurrent connections. This did not only cause emails not being delivered and our users getting an error page, it also caused long running transactions in the database: if you send an email within an after_create hook in a model this happens inside of the database transaction. That means that if you have a 60s timeout on your mail server you end up with database transactions taking 60s to finish (or being rolled back in this case) which essentially locks up your tables after a short period of time.

Now that we are sending our emails from a queue one at a time, the mailserver is happy and our database transactions are again as short as they should be.

You can get the sources at github.

dead simple reports is a Ruby on Rails plugin that allows you to create reports from your application data within minutes. As of now it can not only generate HTML tables and CSV files but also M$ Excel spreadsheets. This is possible through the use of the spreadsheet-excel gem. You can grab a copy from the git repository or just download it from there.

autoki has recently grown into a more and more complex application. Besides two clusters of mongrels and the mysql database we have a memcached server, ferret and starling plus clients for asynchronous processing. WIth so many services running (and sometimes not running) the need to monitor all these grew. We decided to set up nagios on one of the servers - it’s ugly but it lets you monitor all sorts of stuff pretty easily via remote agents that run on each monitored server.

With nagios we have access to quite a number of monitoring plugins, e.g. for monitoring TCP ports (e.g. for checking memcached is still alive), HTTP, server load, free disk space etc. Yesterday I came to a point where I wanted to monitor something nagios couldn’t: When a user uploads a bunch of photos, the task of creating copies of the photos in different sizes is put in a starling queue for asycnhronous processing. If something with that processing goes wrong and the queue gets too big I want nagios to pick this up and notify me. Time for my own nagios plugin.

Nagios plugins are actually very simple. All you have to provide is something that can be executed in a shell and that returns either 0, 1 or 2 for an OK, Warning or Critical state of the monitored service. So here’s the source code for monitoring the number of photo uploads in the queue (RAILS_ROOT/lib/check_photo_uploads.rb):

At autoki the server that runs the asynchronous processes is called jobs1 and this is also where the queue should be checked, so I added this to the /etc/nagios/nrpe.cfg file (the config file for the remote nagios agent):

Then I had to add the service to the nagios configuration on the monitoring server:

Well, that was it, and this is how it looks - ugly but it works

(I recently signup with scout - looks much prettier and the setup is much easier than nagios, plugins are written as ruby classes and it comes as a ruby gem - sweet concept so far, could have been my idea, more on that later)

Na endlich. Nach all den Jahren des nur-Geldverdienens und Open Source-Ausnutzens haben wir es geschafft, ein paar erste Zeilen Code in die Freiheit zu entlassen: dead simple reports, ein Rails-Plugin, das Reports generieren kann. Mehr dazu im neuen Bereich Open Source

Es ist super wenn die Werkzeuge, die man verwendet mit einem wachsen. Deshalb bin ich von Ruby und TextMate begeistert.

Für die, die TextMate nicht kennen: TextMate ist ein TextEditor für OS X, der sich in meinen Augen durch zwei Besonderheiten als Entwicklungswerkzeug hervortut. Erstens die leistungsfähige Live-Suche, die alle Mausklicks zum Navigieren im Projekt überflüssig macht. Zweitens die wirklich mächtigen Skriptingmöglichkeiten, die ich wohl noch lange nicht erfasst habe.

Jedenfalls musste ich Rahmen der Internationalisierung eines Projekts alle Strings in eine Übersetzungsmethode von gettext wrappen. Also ggf. Texte in den Views in Inline tags und in doppelte Anführungszeichen zu packen. Das gewünschte Ergebnis sieht etwa so aus: <%= _("Zu übersetzender Text") %>. Die ganze Arbeit ist ziemlich stupide, ließ sich aber mit TextMate auf simples Markieren des entsprechenden Textes und das Drücken des Tastenkürzels ctrl+alt+t reduzieren.
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Die Konferenzsaison fängt an. Kurz vor der re-publica geht’s am 28./29.3. nach Prag zur European Ruby Conference. Letztes Jahr in Wien war ziemlich lustig. Damals hatten wir in der Nacht zwischen den zwei Konferenztagen ein Twitter-basiertes Rätselspiel (twizzer) geschrieben.

Falls jemand auch da hinwill, wir hätten evtl. noch Plätze im Auto frei.

The latest update from the rspec trunk changed the version.rb file indicating a 1.1 Release Candidate 1 version. Will there finally be a stable RSpec version that has StoryRunner? That’d be a great present for christmas.

Patt Maddoxx recently blogged about a ruby hack to avoid the dreaded nil-if, e.g. if user.comments.first; user.comments.first.title;. instead you can now do: user.comments.first.if_not_nil?{|c| c.title}.
http://evang.eli.st/blog/2007/11/22/smalltalky

dan croak has written a precious little ruby gem that filters the noise from you exception backtraces:
http://giantrobots.thoughtbot.com/2007/12/3/shhh-your-test-unit-backtraces-are-too-noisy