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Phusion Passenger and memcached / memcache-client

I recently switch from a mod_proxy / thin setup to Phusion Passenger and my application started to do the funniest things and the production.log was full with errors related to memcached.

It seems, that passengers spawn method “smart” isn’t compatible with memcached. Within seconds on a lightly loaded server the cache gets corrupted big time.

I got better results with a newer memcache client (the ruby gem actually), but for that i need to remove the client from the rails vendor lib. Furthermore, under higher load there still where errors.

Only solution is to set the spawn method to conservative like so

RailsSpawnMethod conservative

Problem seems to be known in the Phusion and Rails teams.

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Comments are evil?

What can cause this snippet to fail:

<% if !@day.user.is_rateable?  # Workaround für Darstellungsfehler mit Tabellen ohne Bodies im Safari  %>
<!-- blah -->
<% end %>

This little snippet fell apart today. I don’t know if it is passenger, a newer ruby version, RubyInline. All i know is that i am so totally pissed of this incredible amount of incompatible versions of just 3 modules that i literally feel like puking. What a hell of a day.

By the way, the thing that broke was the one-line comment right after the if.

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Localizing dates and time with Rails’ I18n using procs

Ruby on Rails I18n infrastructure did a great job to internationalization in Rails applications. Most things work right out of the box.

Daily Fratze is fully internationalized and i wanted to use ordinal day numbers in the English version. Pity, there is no template for strftime that works that way.

As i already hat monkey patched a “t” method to all date and time related classes, i came up with the following solution:

Parallel to “en.yml” i now have “en.rb” in my locales folder which gets loaded in environment.rb via

config.i18n.load_path += Dir[File.join(RAILS_ROOT, 'app', 'locales', '*.{yml,rb}')]

The en.rb files defines some procs as translation values like so:

{
  :'en' => {
    :date => {
      :formats => {
        :dmy_with_long_month              => lambda { |date| "%B #{date.day.ordinalize}, %Y" },
      }
    },
    :time => {
      :formats => {
        :dmy_with_long_month                       => lambda { |date| "%B #{date.day.ordinalize}, %Y" },        
        :dmy_with_full_day_and_long_month_and_time => lambda { |date| "%A, %B #{date.day.ordinalize}, %Y at %H:%M" }
      }
    }
  }
}

Used with the standard I18n tools you’ll end up with the string representation of the proc object. Useless 😉

So time for monkeypatching like so:

module DateTimeSupport
  def t(format = nil)
    type = self.respond_to?(:sec) ? 'time' : 'date'
    formats = I18n.translate(:"#{type}.formats")
    format = formats[format.to_sym] if formats && formats[format.to_sym]
 
    I18n.localize(self, :format => format.respond_to?(:call) ? format.call(self) : format)
  end
end
 
class Time
  include DateTimeSupport
end
 
class Date
  include DateTimeSupport
end       
 
class DateTime
  include DateTimeSupport
end
 
class ActiveSupport::TimeWithZone
  include DateTimeSupport
end

Code resides in a file in config/initializers and gets loaded automatically. It adds a t method to all date and time related classes. The method tries to look up the translation of format just like I18n/Simple does.

If it is proc, it gets called and then passed to I18n, otherwise it the original parameter is used.

That way the t method can use “dmy_with_long_month”, :dmy_with_long_month and any other arbitrary format like “%B %Y” that is not defined in any language file.

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Grails, Hibernate, Current Session Context

Graeme was so kind to help me with this problem. My app worked well with Grails 1.0.4 but not in 1.1-beta3 any more.

My first wild guess leading to a

HibernateException: contains is not valid without active transaction

exception was my use of annotated Hibernate classes together with additional constraints in Grails, but Graeme figured out that it was the current session context i configured in hibernate.cfg.xml like so:

<property name="hibernate.current_session_context_class">thread</property>

I used this fragment for various JUnit test and in one case in a J2SE application where the same hibernate classes are needed. Together with a JTA Manager, this fragment is not needed and in case of Grails it has to go.

To run my tests i added the following statement right before opening my session:

final Properties nonJtaEnv = new Properties();
nonJtaEnv.put("hibernate.current_session_context_class", "thread");
 
sessionFactory = new AnnotationConfiguration().configure("hibernate.cfg.xml").addProperties(nonJtaEnv).buildSessionFactory();

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Grails startup parameter

Just some snippets from the doku that I tend to forget:

Run grails on a different port:

grails -Dserver.port=9090 run-app

Run grails with a different environment:

grails prod run-app // production
grails -Dgrails.env=mycustomenv run-app  // mycustomenv

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