Dec 22, 2010

network-autoconfig: Find a connected eth interface and create an ifcfg for it

Use case: I want to create an appliance image for a build farm worker machine. I don't know its hardware configuration beforehand; in particular, it may have multiple network interfaces and I don't want to bother figuring out which is which. I will simply include network-autoconfig.rpm and plug the cable into any socket before booting.

network-autoconfig helps setting up machines with multiple network interfaces. At the first boot, all available Ethernet interfaces are cycled until one is successfully configured with DHCP.

I have submitted it to openSUSE:Factory now. Enjoy it in the upcoming openSUSE 11.4!

It is referenced as Feature#311012. You are welcome to improve it on Gitorious.

Nov 16, 2010

dbus-dump

dbus-dump is a tool to capture D-Bus messages in a libpcap capture file.

It takes an idea from dbus-scrape, which processes a strace output of dbus-monitor, and takes it further by stracing dbus-daemon, thus not relying on any eavesdropping (mis)configuration.

The intended purpose is to establish the libpcap capture format as a base for debugging tools like

Thanks to Will Thompson for mentioning the pcap idea.

Usage

$ sudo strace -p `pgrep -f 'dbus-daemon --system'` \
    -s 3000 -ttt -xx -o foo.strace
$ ./dbus-dump foo.strace foo.pcap
$ ./dbus-pcap-parse foo.pcap
Tue Nov 16 12:56:47 +0100 2010 #<DBus::Message:0xb741f340
 @body_length=0,
 @destination="fi.epitest.hostap.WPASupplicant",
 @error_name=nil,
 @flags=0,
 @interface="fi.epitest.hostap.WPASupplicant.Interface",
 @member="scan",
 @message_type=1,
 @params=[],
 @path="/fi/epitest/hostap/WPASupplicant/Interfaces/180",
 @protocol=1,
 @reply_serial=nil,
 @sender=":1.7132",
 @serial=88639,
 @signature="">
Tue Nov 16 12:56:47 +0100 2010 #<DBus::Message:0xb741b060
 @body_length=4,
 @destination=":1.7132",
[...]>

Dependencies

It is written in Ruby. The pcap format is handled by a small bundled module. dbus-dump has no other dependencies. dbus-pcap-parse uses ruby-dbus.

Bugs

This is an early proof-of-concept release, serving to introduce the libpcap format.

The main problem of dbus-dump is duplicating the messages, seeing them both when the daemon receives them and when it sends them (multiple times, for the signals).

The other tools haven't caught up yet:

$ /usr/sbin/tcpdump -r foo.pcap
reading from file foo.pcap, link-type 231
tcpdump: unknown data link type 231

Nov 9, 2010

ruby-dbus 0.5.0 is a Gem with Errors

I have made a new release of ruby-dbus, a Ruby language binding for the D-Bus IPC system.
The main feature is a better binding of Ruby Exceptions to D-Bus Errors. See below for an excerpt of the documentation.
Perhaps more importantly, the library is now primarily packaged as a RubyGem (Issue#6). Also I converted the tutorial from Webgen to Markdown.
Bug fixes:
  • Don't pass file descriptors to subprocesses, they would not let go of the service name.
  • Fixed InterfaceElement::validate_name (Ticket#38, by Herwin Weststrate).
  • Fixed a typo in InvalidDestinationName description (Ticket#40).
RPMs can be found via openSUSE Build Service Search.

Errors

D-Bus calls can reply with an error instead of a return value. An error is translated to a Ruby exception.
begin
    network_manager.sleep
rescue DBus::Error => e
    puts e unless e.name == "org.freedesktop.NetworkManager.AlreadyAsleepOrAwake"
end

Replying with an error

To reply to a dbus_method with a D-Bus error, raise a DBus::Error, as constructed by the error convenience function:
raise DBus.error("org.example.Error.SeatOccupied"), "Seat #{seat} is occupied"
If the error name is not specified, the generic org.freedesktop.DBus.Error.Failed is used.
raise DBus.error, "Seat #{seat} is occupied"
raise DBus.error

Aug 29, 2010

n2n package improved

Root.cz recently ran an article (in Czech) about the n2n virtual private network sofware, an open alternative to Hamachi. I intend to use it to cross the NAT in my mom's DSL modem so that I can connect to her computer with ssh and VNC.
Thanks to happyman_eric and Grief, openSUSE Build Service already contained a package. I have made an improved version, adding an init script and a sysconfig file. Get the sources in my home project, or the binaries.

Aug 20, 2010

ruby-dbus 0.4.0 with TCP Transport

I have made a feature release of ruby-dbus, a Ruby language binding for the D-Bus IPC system.
  • TCP transport which pangdudu coded a year ago. At that time I did not feel familiar enough with the library, and the test suite was much smaller too, so that's why it took me so long.
  • Enabled test code coverage report (rcov)
  • Classes should not share all interfaces (Ticket#36/Issue#5)
  • Ruby 1.9 compatibility (Ticket#37, by Myra Nelson)
RPMs can be found via openSUSE Build Service Search

Aug 10, 2010

Who does not want such a gift

This post is showing naked women packaged as a present (for openSUSE's 5th birthday) and asks Ah... who does not want such a gift, eh.

I believe that the female users and contributors of openSUSE don't. It reduces them to pretty things, judged on their looks instead of their contribution.

Raul, please stop such sexist postings. Your blog is your own, but keep it out from Planet openSUSE.

Just in case common sense is not enough, let me quote for reference the relevant section of the openSUSE Guiding Principles:

We value... respect for other persons and their contributions, for other opinions and beliefs. We listen to arguments and address problems in a constructive and open way. We believe that a diverse community based on mutual respect is the base for a creative and productive environment enabling the project to be truly successful. We don't tolerate social discrimination and aim at creating an environment where people feel accepted and safe from offense.
and the activities in order to excel in our goals: Emphasize the value of communication and recognize cultural diversity within our community.

Aug 5, 2010

Upgraded to openSUSE 11.3

I have upgraded my office workstation to openSUSE 11.3 today. Here I document the migration so that you don't have to repeat my mistakes.

I went via the command line and ventured to keep all additional repos enabled. So switching the repos was done simply by sed -i "s/11\.2/11.3/g" /etc/zypp/repos.d/*

The KDE session crashed after kdelibs4-core had been updated. No big deal, so I ran zypper dup again.
The /home directory is mounted via NFS, so filesystem.rpm failed when it wanted to reset the permissions of /home. Updating it explicitly after unmounting /home was easy, only unmounting it was harder because the crashed session left processes still accessing the home. fuser -v /home found them.

The NFS mount is also authenticated by Kerberos and there is a bug so I got
mount.nfs: access denied by server while mounting nfs.example.com:/home
I had to rebuild and update a package and tweak a config file. See bnc#614293 for the details (thanks to mcaj for the reference).

Jul 22, 2010

ruby-dbus 0.3.1

I have made a bug-fix release of ruby-dbus, a Ruby language binding for the D-Bus IPC system.
  • Many on_signal could cause DBus.Error.LimitsExceeded (bnc#617350).
    Don't add a match rule that already exists, enable removing match rules. Now only one handler for a rule is called (but it is possible for one signal to match more rules). This reverts the half-fix done to fix Issue#3.
  • Re-added InterfaceElement#add_param for compatibility.
  • Handle more ways which tell us that a bus connection has died.
RPMs can be found via Webpin.

Jul 2, 2010

Helping Newcomers

Since the discussion (do check out the linked paper, BTW) and the opensuse-women announcement, I've been thinking about how to make the openSUSE community more friendly to women.

I think one good way is to make sure that new people feel welcome when they join a conversation, be it on the forums, on IRC or on the mailing lists. Now this would be easier if we all had infinite time to read and answer all questions, but as we don't, I decided to focus somehow.

The forums provide a handy shortcut for the focus, labeling a user who made few posts as a "Puzzled Penguin". So I've made a simple service, a feed of http://forums.opensuse.org showing only the posts by newcomer users: http://vidner.net/martin/software/rss-creator-blacklist

(Actually right now it does not show Puzzled Penguins only but instead excludes the 100 most-posting users until I learn how to optimize the PHP code.)

Jun 30, 2010

kiwi2puppet

I have started working on kiwi2puppet, a tool to convert KIWI image descriptions to Puppet manifests.

The goal is to recycle the data that went into the building of an image and use it for managing a deployed appliance.

So far it is a prototype that can write these resources
  • package
  • yumrepo
  • user
  • group
It is written in Ruby, like Puppet.

Source at GitHub: http://github.com/mvidner/kiwi2puppet
RPMs: http://software.opensuse.org/search?q=kiwi2puppet&baseproject=ALL (currently it is a single Ruby script, so at the moment RPMs are not worth any trouble)
Novell Reference: FATE#309497

Get in touch if you're interested.

In case you didn't know:
"The openSUSE KIWI Image System provides a complete operating system image solution for Linux supported hardware platforms as well as for virtualisation systems like Xen Qemu or VMware."
"Puppet is an open source data center automation and configuration management framework. Puppet provides system administrators with a simplified platform that allows for consistent, transparent, and flexible systems management."

Mar 28, 2010

ruby-dbus 0.3.0 Works on Ubuntu

ruby-dbus has for a long time not worked on the default Ubuntu desktop. I thought I had fixed it in 0.2.12 but that was only for the server side. In fact, clients had another bug and I have released version 0.3.0 today to fix it.

NEWS:
Bug fixes:
  • Fixed "undefined method `get_node' for nil:NilClass" on Ubuntu Karmic (Ticket#34).
  • Get the session bus address even if unset in ENV (Issue#4).
  • Improved exceptions a bit: UndefinedInterface, InvalidMethodName, NoMethodError, no RuntimeException
These are by Klaus Kaempf:
  • Make the signal dispatcher call all handlers (Issue#3).
  • Run on Ruby < 1.8.7 (Issue#2).
  • Avoid needless DBus::IncompleteBufferException (Ticket#33).
  • Don't ignore DBus Errors in request_service, raise them (Ticket#32).
Features:
  • Automatic signature inference for variants.
  • Introduced FormalParameter where a plain pair had been used.
RPMs can be found via Webpin.

Feb 18, 2010

Reinventing

[S]ometimes, when you are designing systems it is hard to realize that the circular friction reduction device with a central axis that you have just built is, in fact, a wheel.

-- Russ Olsen, Design Patterns in Ruby, p.4

Jan 24, 2010

Service Activation Fixed in ruby-dbus 0.2.12

Today I fixed a long-standing bug in ruby-dbus where a service activated by the bus would fail with "undefined method `get_node' for nil:NilClass" (tickets #25 and #29).
RPMs can be found via Webpin.