uninitialized constant MysqlCompat::MysqlRes

Then the following build line for the mysql gem might fix it for you:

ARCHFLAGS="-arch i386 -arch x86_64"  \

  gem install --no-rdoc --no-ri mysql ]] \

  -- --with-mysql-dir=/opt/local/lib/mysql5 \

  --with-mysql-config=/opt/local/lib/mysql5/bin/mysql_config

$ sudo gem install pg
Building native extensions.  This could take a while...
ERROR:  Error installing ruby-pg:
ERROR: Failed to build gem native extension.

The solution is quite simply. Just make sure pg_config can be found by the gem installer.

$ mdfind pg_config|grep bin|uniq
/opt/local/lib/postgresql83/bin/pg_config

In this case make sure /opt/local/lib/postgresql/bin is available in the path when executing the gem command

$ PATH=/opt/local/lib/postgresql83/bin:$PATH sudo gem install pg

Far too many times have things failed because of a dead worker in the cluster or some stale or (even worse!) non-existent pidfiles on the system. Mongrel has served well, but it’s time to look for something better.

A typical setup I use is nginx as the front-end server doing all static content while a pack of mongrels is handling the Rails requests through reverse proxy. nginx is also very important for reproxying requests, where content is streamed from another internal server over the front facing servers. In most of the Rails app I’m writing I have to deal with very large files (audio, video) so reproxy is essential if you want to have any sort of performance on a reasonable budget. Since Apache2 lacks reproxy support (AFAIK, please prove me wrong!) I really want to keep nginx as the front-end server and then do the Rails handling with Apache2 + Passenger through reverse proxy.

I’ve come a cross a couple of posts on this very topic.

I’ll be doing some heavy development and testing over the next couple of days with this setup, will post my findings…

I really like the instructional video’s made by the TVFlat crew, very helpfull tips for creating your own video content.

Technology used:

• Linux
• Nginx HTTP server
• Mongrel
• MogileFS clustered storage
• Rails 2.0.2
• Merb 0.54 for critical code paths, beats Rails to a pulp when it comes to roundtrip times
• Memcached
• MySQL
• Lucene
• mplayer / ffmpeg / faac for transcoding, direct broadcast quality feeds are generated!
• Flash video

Hope I can find some time later on to write a bit about the different parts.. anyway, go check it out!

Enter JRuby. Since the main code blob of this project is captured in a Mongrel plugin I thought about just deploying the whole of Mongrel on JRuby. Unfortunately JRuby Mongrel support was not there yet (Mongrel 1.1 supports JRuby). So the next best thing was to build some kind bridge between JRuby and Ruby + Mongrel + Plugin. Distributed Ruby (DRb) is a perfect fit:

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#
# server.rb (this)
# jars/big-bad-service.jar
#
APP_ROOT = File.join(File.dirname(__FILE__), '.')

require 'java'
require 'drb'

require "#{APP_ROOT}/jars/big-bad-service.jar"

BigBadService = com.blah.BigBadService

class JRubyServer
  def initialize
    @bbs = BigBadService.new
    @bbs.initialize_service
  end

  def bbs_call(param) 
     @bbs.bbs_call(param)
  end
end

if __FILE__ == $0
  DRb.start_service 'druby://127.0.0.1:6666', JRubyServer.new
  DRb.thread.join
end

Execute like ruby server.rb, and then you’ll have the server listening on port 6666 of localhost. Nice, we can now call our Java service from other Ruby code with this simple snippet:

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require 'drb'
DRb.start_service

java_bbs = DRbObject.new(nil, 'druby://127.0.0.1:6666')

puts  java_bbs.bbs_call("Whack!") #=> "Whacked!"

Kewl! Except for one big caveat. As of JRuby 1.0.x Java objects cannot be marshalled correctly so passing them to your Ruby code will cause all sorts of interesting hangs and crashes when you access them concurrently (see JRUBY-1235). Untill JRuby 1.1 is out you can synchronize all your calls to JRuby and making sure you convert any results to proper Ruby objects before using them elsewhere in your Ruby code.

This hack saved me loads of (Java hacking) time!