class T
  def test
    puts "test"
  end

  def lest
    puts "lest"
  end

  def m
    test
  end
end

T.new.m
T.send(:define_method,:m_a) { lest }
T.send(:alias_method, :m_old, :m)
T.send(:alias_method, :m, :m_a)
T.new.m
T.send(:alias_method, :m, :m_old)
T.send(:undef_method, :m_a)
T.send(:undef_method, :m_old)
T.new.m

as you can see after modification class is exact same as before ( except if there is method a, but it is possible to handle it via introspection and dynamic choose of method). I don’t need to change whole stack of calls to add parameter or introduce new singleton class which can have flag.
I hope it help someone with his fix of not so well written piece of software.

• ActiveResource Behavior
• Actively maintained ( and will be due to SLMS support )
• Tightly developed with guys from studio team
• Well documented with yard
• Good test coverage

I think then a lot of glory words is better to show example. It is example based on example from documentation.
Example goal is simple. Create new appliance in studio, add own cool rpm and build appliance with it. It can be useful to test your new version of software in stable environment and have automatic appliance in which you can test it.

  require 'rubygems'
  require 'studio_api'

  # Fill up Studio credentials (user name, API key, API URL)
  # See https://susestudio.com/user/show_api_key if you are using SUSE Studio online
  connection = StudioApi::Connection.new('user', 'pwd', 'https://susestudio.com/api/v1/user')
  # Setup the connection for all ActiveResource based class
  StudioApi::Util.configure_studio_connection connection

  # Find template with KDE4 for SLE11SP1
  templates = StudioApi::TemplateSet.find(:all).find {|s| s.name == "default" }.template
  template = templates.find { |t| t.name == "SLED 11 SP1, KDE 4 desktop" }
  # clone template to new appliance
  appliance = StudioApi::Appliance.clone template.appliance_id, :name => "New cool appliance", :arch => "i686"
  puts "Created appliance #{appliance.inspect}"

  #add own rpm built agains SLED11_SP1
  File.open("/home/jreidinger/rpms/cool_rpm-1.0-1.60.noarch.rpm","r") do |f|
    StudioApi::Rpm.upload f, "SLED11_SP1"
  end
  # and choose it in appliance ( and of course add repository with own rpms)
  appliance.add_user_repository
  appliance.add_package "cool_rpm", :version => "1.0-1.60"
  #check if appliance is OK, like dependency problems with new rpm
  if appliance.status.state != "ok"
    raise "appliance is not OK - #{appliance.status.issues.inspect}"
  end

  build = StudioApi::RunningBuild.new(:appliance_id => appliance.id, :image_type => "xen")
  build.save
  build.reload
  while build.state != "finished"
    puts "building (#{build.state}) - #{build.percent}%"
    sleep 5
    build.reload
  end

  final_build = StudioApi::Build.find build.id
  puts "Appliance to download: #{final_build.download_url}"

So I hope that you like interface how I design it. Of course I welcome any suggestion how to improve it. You can use comments here, novell bugzilla or issues on github.
How to install it:

• In opensuse: 1-click for 11.3 and 1-click for factory
• alternative possible everywhere is to use
  gem install studio_api

At the end few useful links if you are interested:
repository on github
yard documentation
gem at rubygems.org

Thanks for attention and I welcome any comments

as hackweek continue I want to present my contribution for this year event. My plan is to support our the youngest supported desktop environment LXDE. So I contact our LXDE guy Andrea Florio and he ask lxde developers. Then we communicate directly and I found as the most intersting idea to replace gnome gvfs which is needed to have usable gio interface in glib ( geek-deserialization: allow easy access remote systems, zip archives in file manager like it is part of filesystem). Motivation for replacement is quite big gvfs dependency and system resource requirements. It choose it because I can learn something new, can return to programming in C from Ruby on Rails which is used for webyast and last not least I think it is usable also for another lightweight environment xfce4.

Code can be located in pcman git repository. Idea of implementation is quite simple. Don’t use daemons and special code to handle different backends. Instead use fuse and its already written fs based on fuse. As first I start with ftps and its sshfs implementation. Code for single fs is simple and short. Today I finish first working proof of concept of gvfs extension and its gfile extension. It can query and copy file on gvfs as you can see in file gfusevfs.c where is testing program. Main problem which I still see is that fs is not umounted so it takes some sources, but umount it after file operation can lead to annoying behavior like passing password on each file operation.

I welcome any comments and ideas about this project.

And thats all to watch your server usage.

I found useful information on our wiki – Creating modified installation system. But I don’t want install from network, as it doesn’t shown same menu as on DVD. I try use mkisofs, but it is not easy set same boot sector as have original iso image. And there I found good software – isomaster. This allows you to replace file on iso image and remember from original iso image where it has its boot sector. This iso should be easily tested in e.g. Virtual Box and I can verify, that my fix work before we release first DVD with opensuse 11.2. Just sidenote – linuxrc show warning, that your inst-sys doesn’t match checksum.

Same way is possible edit whole LiveCD. Simple mount and copy content of live system to your disc and with zypper –root you can change software in your LiveCD. Then create squashfs ( I use mksquashfs live_root  openSUSE-kde-11.1-read-only.i686-2.7.0 -no-duplicates -noappend ) and with isomaster replace file openSUSE-* and you have your modified liveCD.

Official features

First I look on official features. I think most important is automatic test suite. This is set of automatic test, which test again interface of library (it is black box testing). Before release of 11.1 this test suite contain 232 tests. I hope this increase quality of each perl-Bootloader release, because this suite catch many problems and also if new occur I add to it (this should prevent regression). Only problem with this test suite is that it doesn’t test whole kernel upgrade. It is hard to due, because kernel upgrade must fill itself hardware informations and if I want test it correctly I must simulate it with actual utilities which is used and on many types of hardware. So this part should be improved, but need some idea how test many hardware configuration (like different RAIDs (linux and bios), LVMs, multipath, different hardware architecture (like macos, efika or chrp on powerpc)) on one machine.
Another feature is consistent device names. This is most problematic feature, because it is hard to resolve many different devices given by udev (also udev is broken during some part of development). I experiment with many different sollution and at final I decide (it is after last beta) to create function which translate everything to kernel device and then compare that device to another translated device (previous solution based on filling all symlinks also work, but after device mapper problem with udev(more lower) I change it to more efficient and more reliable solution).
Next feature you can use if you have machine with chip to trusted computing (some notebooks have it). More about trusted computing you can read here. Most work did thorsten duwe (maintainer of grub) and in final I only ensure that due to security reason no splash screen is loaded (I remove message line even if user want it). If you have pc with GPT table and x86_64 processor you must for 11.0 use legacy booting. Now you can use ELILO bootloader (which have support efi) also on x86 architecture. This is also quite easy to implement, but harder to ensure it works, because get hardware with that configuration is not so easy. Only short notes for another features. Old disks which uses C/H/S is dropped and LBA is forced, kernel append during upgrade is taken from sysconfig and add support for disk remapping for windows entries.

Enhancement

Difference between feature and bug is really small and maybe some of enhancement looks more like bug and vice versa. For me interesting enhancement is check, if /boot is mounted. I use it at home quite often, because if you have separate home you needn’t mount it, but if during update also kernel is updated I often forgot mount it. First implementation is not ideal and I get many experience, that some users have really exotic entries in fstab, which of course bad match to check pattern. But after three iteration and one work-around this work quite good and I am satisfied with it. Another enhancement (really close to bug) is none bootloader. It is special bootloader settings, which ensure that nothing happen during kernel upgrade. It is quite useful if kernel update mess your configuration (which is bug, but you want prevent it until I fixed it) or take to much time (this is also bug). More important usage is for netboot, when you needn’t any bootloader, because you boot via PXE.
Important enhanced is stop kernel install, if bootloader update fail (problem is in using tee in pipe and ignore script return value). It is good, because you know that something goes wrong and reload backup. Also because usually new kernel is installed first, you still have old kernel and can boot it. Last enhancement is for anyone who want look how perl-bootloader works inside. Now you can use make doc in sources and it generates html page from comments (something like javadoc). Beside this documentation together with Jozo Uhliarik we create wiki page about interface of library and anyone who want use perl-Bootloader should use it.

Bugs

Solving bugs in perl-Bootloader is not so interesting as it looks like . You need analyze many long logs (if perl-Bootloader uses yast, then it is saved to y2log, if used by kernel upgrade then save to perl-BL-standalone log) and find what and when going wrong. You find what is wrong, but not who break it. Sometime it is bug in parsing configuration, sometime in parsing output of external commands and sometime is bug outside (like break udev). Source code (also with test suite) have 15k LOC and when I try look how many line I change (oneliner for it `find . -type f 2>/dev/null | grep -v .svn | xargs svn blame | grep jreidinger | wc -l `) I find, that I change 3k LOC. So code base is good, but need some improvement. I note some interesting bugs, which I solve.
One is longterm problem with chainload, when as root is current mounted root, but chainloader key is with right prefix (root of chainloaded partition). This on some hardware causes problems and now root is correctly set and I don’t have any negative responses (so I hope it works).
Another one is also quite long term problem when you change flavor of kernel, sometime previous kernel is uninstalled and after that new installed (normal work-flow is install new and uninstall old). Of course it switch default, which is quite annoying. Fix this is quite tricky, and trick is that after remove last image section and if it is default, I add comment about that and when new kernel is added, then set it as default. That fix works quite good, but after sent iso to factory (for boxes) I get bugs, that if you update via YaST, it doesn’t work. Problem is in some deprecated code which overwrite my comment by another one. Fix is easy, I only remove deprecated code, which cause it. So if you after install of opensuse11.1 see update of perl-Bootloader you know why. As late update is also solved problem with hanging kernel update. It take too much time because when I read logs I add useful logging lines to code (I hope it help me next time find problem faster) and when log records reach some level, it take too much time (due to array copying of records). I reduce debug logging and also improve whole performance of logging, so I hope it significant improve time to kernel update (at least it should not take minutes to upgrade bootloader configuration).
Not every bug is problem of perl-Bootloader, but you must solve it in code. Example is device mapper and udev inconsistency. Udev points to /dev/dm0, but device mapper to /dev/mapper/something. This became real problem when persistant names feature is implemented. Solution is also little tricky, udev define variables for links and one of that variable is DM_NAME for name of device and DM_PART for partition number and with this information I can construct whole /dev/mapper/name. I find this solution as working, but not much robust. If someone know better, (s-)he is welcome to write it to comment. Also many perl warnings is fixed, it usually doesn’t break anything, but it looks really unprofessional.
Now I have only 2 unresolved bugs (both is enhancement on which I work) and wait for another, so report all problems in opensuse11.1, I don’t throw it to bin

This is my first work with build service and It take me two hour to package this applications. So don’t wait and also prepare your own package for software which you miss in opensuse. But at first try search , if someone before you doesn’t make it and share his(her) work with you.

If you want maintain your configuration manually, you can simple set your bootloader to none. There is two ways how you can do it. First is set LOADER_TYPE=”none” in /etc/sysconfig/bootloader. Second is set this in yast2 bootloader. Another advantage is that this take almost no-time, so if obtain hardware configuration for update take to much time, this is workaround.

Warning, if you set bootloader type to none you must manually edit your bootloader configuration after kernel update. What can help you, is set image and initrd to symlinks which lead to actual kernel.