Green Chile Would Make This Blog Taste Better

The pseudo-random musings of Tim Chavez.

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Just got back from Copenhagen, Denmark

I really enjoyed UDS R (Ubuntu Developer Summit R).  Copenhagen is a lovely city and I felt that the 4 day schedule was adequate to get done what needed getting done.  My sincere hope is that we can move forward this cycle to deliver a shiny new Ubuntu image building web-based front-end to the various Ubuntu flavors!  I'll try to write more on this later.

In other news, I came home from UDS to a busy week of packing, moving, and closing on the sale of my Condo.  Brooke, Sophie and I are moving into an apartment for the next 6 months while we wait for our new home to be built.  I invested a lot of blood, sweat, and tears into renovating this place, so leaving, especially to an apartment, has me a little down trodden.  I'm sure I'll feel better when we move into our new home -- our first house -- and start making memories in it.

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Busy being a dad

I have seriously neglected this blog.  I should write something....

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Twitter's IPA

Hello,

Seeing that caniszczyk is a committer, I can assure you that they picked the acronym first :)

https://github.com/twitter/innovators-patent-agreement

Sadly, I bet there is a patent troll out there who already owns the patent on this contractual agreement...

I hope more companies will commit to this agreement or one like it even if it comes with a cost (e.g. a lower valuation due to the crippled IP? *shrug*).  Doing evil with software patents is all too easy.  This sort of tactic will hopefully make it less so.  I commend Twitter for taking the stance publicly and in writing.

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Add an Ubuntu badge to your video stream :)

Wow.  I haven't posted a blog in quite some time.  I've been focused on being a dad, husband, and better programmer.  However, with the introduction of "masks" in Google+ Hangout, I've recently become obsessed with video processing and gstreamer in particular.  So let me just cut to the chase:

Steps to placing an Ubuntu badge in your video stream:

0. Buy a webcam :)

1. Install Ubuntu (Precise Beta1!!)

2. Install the Video 4 Linux (v4l2loopback) driver, this will allow you to create a "virtual webcam" so-to-speak,

# sudo apt-get install v4l2loopback-dkms # sudo modprobe v4l2loopback

3. Download your badge,

# wget https://help.ubuntu.com/11.10/ubuntu-help/figures/ubuntu-logo.png

4. Composite your webcam's video with a static image (the badge) and write it to the "virtual webcam" (for consumption in Google+ Hangout, for example),

The Cody Somerville-optimized version:

# gst-launch-0.10 multifilesrc location=ubuntu-logo.png caps='image/png,framerate=1/1' \ ! decodebin2 ! videobox border-alpha=0 alpha=.75 top=-80 left=-20 ! videomixer name=mix \ ! ffmpegcolorspace ! v4l2sink v4l2src ! ffmpegcolorspace ! \ 'video/x-raw-yuv,width=640, height=480' ! mix.

Here you'll see that the 'imagefreeze' plugin was scrapped for the multifilesrc which is quite clever.  The multifilesrc is designed to loop through a collection of file sources at a given framerate.  Here, Cody, is simply looping over the same image, faster than the eye can see.  Significantly improves performance over the original version that I posted!  Thanks!

Original version:

# gst-launch-0.10 filesrc location=ubuntu-logo.png ! decodebin2 ! imagefreeze ! videoscale ! \ videobox border-alpha=0 alpha=.75 top=-80 left=-20 ! videomixer name=mix \ ! ffmpegcolorspace ! v4l2sink v4l2src ! videorate ! ffmpegcolorspace ! video/x-raw-yuv, \ framerate=\(fraction\)10/1, width=640, height=480 ! mix.

5. Start or join a Google+ Hangout and click on the  settings icon, click on the first drop down, and choose "Loopback video device",

6. You're all done. Because this is compositing (in a manner of speaking) the image to your physical webcam video stream and writing it to the "virtual webcam", you should in theory be able to use this with any application that lets you choose your video source. Woo.

The astute Ubuntu user will notice that the logo is flipped :(  This may just be a Google+ Hangout thing?

If you are a gstreamer pro, I would love to know if this could be further optimized so that I can use my native resolution without my laptop crying :)

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Sophie (8 or 9 weeks or so) posing on her blanket.

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Sophie (3 or 4 weeks old) on her super cool Linux blanket that our friend Meghan made for us.  It reads:

Sophie For Brooke and Tim's first baby girl From Meghan and Ben:)

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*squeek*

I realize that I have not updated my blog for quite some time.  The reason mostly has to do with the the birth of my daughter, Sophie.  My wife and I are still getting adjusted to being new parents.  Other than that, I have been quite busy with work.  Not only did my team merge with another, we are in the process of "end-of-life"-ing a bunch of commercial projects which is taking a considerable amount of time to get through.

I'm at UDS/P in Orlando, Florida this week, so I thought it would be a good time to reestablish my commitment to blogging about the web services, libraries, and tools that are essential to my day-to-day job at Canonical.   I've decided to share more of my personal thoughts and opinions of regarding Ubuntu and its community.  And while I'm making promises to myself (since I don't actually think anyone but me reads this), I will also be writing a UDS/P retrospective.  Woo.

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Camea Decibel Festival Podcast 2011

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This is an excellent mix.  A perfect compliment to a morning, afternoon, or evening hacking session ;)

Alternated Tones - Luciano Red Dust (Ryan Davis Sub Dub) - Andre Sobota Masters Of Nothing - Cosmic Cowboys Abends - George Townston Circunbalation V - Tadeo The Scent - Karl Johan Back In The Day - Mitja Prinz Morning Calling - Arthur Oskan Deep 2 - Diego Physical - Manuel Tur's Black Body Radiation Remix - The Quantum Mechanics Monday (Marcus Sur Remix) - Plusculaar Fall from Grace - Myers Briggs

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Submitting a form with GET using Django's FormView

Let me just put it out there.  I'm one of those people who think submitting form data with GET is a perfectly reasonable thing to do when implementing search functionality.  If you use Django and think like I think, then you should know the following:  This behavior is not currently implemented for Django's generic FormView (dpkg -l python-django tells me I'm using 1.3-2).  Submitting a form using GET will provide no form validation.  Luckily for us, Django's class-based views were designed to be customized and extended,  and thanks to Daniel Swarbrick, we have some code to do just that:

def get_form_kwargs(self): kwargs = {'initial': self.get_initial()} if self.request.GET: kwargs['data'] = self.request.GET return kwargs

This method can either be provided by a shiny-new MixIn class or it can be added as an override to an existing FormView.  If you're asking me for my opinion on which way to go, then I'll give it: I prefer the MixIn approach because it's simple and reusable :)

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Creating PPAs using the Launchpad API

This has technically been possible since October 2010 due to the efforts of Steve Kowalik and Cody Somerville (see branch).  Google searches for "create ppa via api" or "create ppa using api" do not reveal an immediate example of how one might do this, so I'll document it here, and hope that one day it filters to the top?  It's super easy!

create_ppa_via_api.py

import sys from lazr.restfulclient.errors import HTTPError from launchpad import launchpad_production_session # Borrowed from this post launchpad = launchpad_production_session("create-ppa-app") try: ppa = launchpad.me.createPPA(name="shinynewppa", displayname="Shiny New PPA", description="A Shiny New PPA!") except HTTPError, error: sys.exit(error)

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It turns out my patronus is a Lonestar Tall Boy.  Sweet! I made this beauty with Gimp today (but don't blame Gimp for this monstrosity, blame me!)

[mareen]

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I wished I worked in a space like this!

mareen:

Looking for a studio or office in Düsseldorf-Flingern?

I have something available because I am moving my studio to Cologne soon. Check it out on ImmoScout.

Please contact me here.

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Handy little Launchpad module to get a persistent session / switch users on-the-fly

From time to time I'll need to quickly extract some bit of information from Launchpad.  Or, depending on what I'm actually after, I may even have to switch users to get what I need (e.g. P3A subscription URLs for a particular user).  To achieve both of these goals, I've whipped up a handy little module (like I'm sure others who work w/ Launchpad have) to give me back a new session if its the first time running or a cached session if it ran before.  

Here is a the module followed by a basic script that uses it:

launchpad.py

import os from launchpadlib.launchpad import Launchpad from launchpadlib.uris import LPNET_SERVICE_ROOT, STAGING_SERVICE_ROOT from launchpadlib.credentials import Credentials from lazr.restfulclient.errors import HTTPError CACHE_DIR = os.path.expanduser("~/.launchpadlib/") def launchpad_session(app_name, service_root, version): app_creds = CACHE_DIR + app_name if os.path.exists(app_creds): credentials = Credentials() credentials.load(file(app_creds)) lp = Launchpad(credentials, service_root, CACHE_DIR, version=version) else: lp = Launchpad.get_token_and_login(app_name, service_root, CACHE_DIR, version) lp.credentials.save(file(app_creds, 'w')) return lp def launchpad_production_session(app_name, version="devel"): return launchpad_session(app_name, LPNET_SERVICE_ROOT, version) def launchpad_staging_session(app_name, version="devel"): return launchpad_session(app_name, STAGING_SERVICE_ROOT, version)

bulk_set_archive_dependency.py

#!/usr/bin/python from launchpad import launchpad_production_session launchpad = launchpad_production_session("bulk_set_ubuntu_deps") me = launchpad.people['timrchavez'] distros = launchpad.distributions ubuntu = distros['ubuntu'].main_archive for ppa in me.ppas: print ppa.name print ppa.addArchiveDependency(pocket="Release", dependency=ubuntu)

Now, to be fair, switching users is not actually "on-the-fly" the first time 'round because they have to be authenticated.  However, once they are, credentials are cached, and switching users becomes on-the-fly!  I'm not sure if this is something very many people actually need to do in practice, though, so if you're just looking for a way to quickly grab a session, I think this module could still help :)

Right now switching users requires interaction with the browser, but I wonder if it can be done programmatically.  I think it's something worth investigating.

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A "Read Later" solution for Google+

Since joining Google+, I've noticed a propensity for long conversations to form around topics that interest me.  However, I'm often time-constrained, so I'm unable to read the entire conversation in one sitting.  By the time I am able to get to it, the conversation is usually buried or I've already forgotten about it.

My friend Klaus W. suggested the following:  Just share with a "read later" circle that just has yourself as a member.

Works pretty well :)  Thanks Klaus!

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Pushing a branch to Launchpad using bzrlib

Friend and colleague, Cody Somerville, showed me how to push a BZR branch to Launchpad using bzrlib (last couple lines). I thought I'd document this here, since I banged my head on this for a couple hours before giving up. Obviously you'll need to modify the code to suit your needs...

from os import chdir from bzrlib.transport import get_transport from bzrlib.branch import Branch from bzrlib.workingtree import WorkingTree REMOTE_URL="bzr+ssh://bazaar.launchpad.net/~timrchavez/+junk/foo" PUSHTO_URL="bzr+ssh://bazaar.launchpad.net/~timrchavez/+junk/bar" LOCAL_BRANCH="foo-example" # Location of branch on Launchpad remote_branch = Branch.open(REMOTE_URL) # Location of branch on local system local_branch = remote_branch.bzrdir.sprout(LOCAL_BRANCH).open_branch() # Change a file in the local branch try: f = open(LOCAL_BRANCH + "/README", 'w') except IOError, error: raise IOError, error else: f.write("BAR") f.close() # Commit the change tree = WorkingTree.open(LOCAL_BRANCH) tree.commit("Setting README to BAR") # Push back to Launchpad transport = get_transport(PUSHTO_URL) local_branch.create_clone_on_transport(transport)

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Adding archive dependencies via the Launchpad api

Thanks to the efforts of, Aaron Bentley, we now have the ability to add and remove archive dependencies to Launchpad PPA's via the launchpadlib API.

The new API call, addArchiveDependency, takes two required arguments: 

dependency - a URL to an archive; and

pocket - Release, Security, Updates, Proposed, or Backports

And one optional argument:

component - e.g. main.  Note, that if you specify a component other than "main" (e.g. universe), it will automatically include "main" as a dependency in addition to the component you specify.

Here is some example code:

from launchpadlib.launchpad import Launchpad from launchpadlib.uris import LPNET_SERVICE_ROOT from lazr.restfulclient.errors import HTTPError launchpad = Launchpad.login_with("foo", LPNET_SERVICE_ROOT, version="devel") ubuntu = launchpad.distributions['Ubuntu'].archives[0] # Primary ppa = launchpad.me.archive try: ppa.addArchiveDependency(dependency=ubuntu, pocket="Release") except HTTPError, error: if error.response.status == 400: ppa.removeArchiveDependency(dependency=ubuntu) print "Removed %s as an archive dependency for %s" % \ (ubuntu, ppa) else: print "Added %s as an archive dependency for %s" % \ (ubuntu, ppa)