Freenode Infra-Talk Channel

I've spent the last few years trying to find the holy grail of FOSS toolchains for producing and displaying my presentations.

I started with OpenOffice.org Impress (which I have sworn never to use again after it ate several presentations), dallied with Clutter's opt, seriously used KeyJNote, before moving to Mac OS X last year and settling on Apple's Keynote.

While travelling this year without a Mac, i've resumed my search for the perfect toolchain, and I think i've found a setup that works pretty well.

It's uses Inkscape to build the slides, a text file to order slides, KeyJNote to display them, and Rake to tie it all together. Oh, and it's versioned with Bazaar.

Each slide goes on a new line in order.txt:

/home/auxesis/Desktop/devopsdays/slides/blank.png
# http://www.flickr.com/photos/tim_norris/2600844073/
/home/auxesis/Desktop/devopsdays/slides/scalable.png
# http://www.flickr.com/photos/barbour/404053639/
/home/auxesis/Desktop/devopsdays/slides/distributed.png
# http://www.flickr.com/photos/numstead/535460927/
/home/auxesis/Desktop/devopsdays/slides/nagios-plugin-format.png

You can easily add comments between slides to keep track of image sources or write down ideas.

Then there's a Rake task for building the KeyJNote command line and setting up displays:

desc "setup external displays"
task :displays do
  system("xrandr --output VGA --mode 1024x768")
  system("xrandr --output VGA --same-as LVDS")
end
 
desc "perform presentation"
task :perform => :displays do
  options = "--transition Crossfade --transtime 250 -c persistent"
  command = "keyjnote #{options} @#{File.dirname(__FILE__)}/order.txt"
  system(command)
end

Finally, there's a Rake task for building the PNGs from the SVGs created through Inkscape:

desc "build pngs from svgs"
task :build do
  Dir.glob("sources/*.svg").each do |file|
    if modified?(file)
      basename = File.basename(file, '.svg')
      slide = "slides/#{basename}.png"
      system("inkscape -e #{slide} -f #{file}")
    end
  end
end
 
def modified?(filename)
  index_filename = File.join(File.dirname(__FILE__), "cache", "index")
  # read or initialise index
  if File.exists?(index_filename)
    @index = File.open(index_filename, 'r') { |f| Marshal.load(f) }
  else
    @index = {}
  end
 
  # check if modified
  if @index[filename]
    modified = File.mtime(filename) > @index[filename][:mtime]
  else
    modified = true
  end
 
  # update index
  @index[filename] = {:mtime => File.mtime(filename)}
  File.open(index_filename, 'w') { |f| Marshal.dump(@index, f) }
 
  return modified
end

This keeps an index of SVG mtimes, and only rebuilds a slides if you modify the SVG.

Then to view the presentation, it's a simple:

$ rake build ; rake perform

Now that you're just dealing with a bunch of files, you can version control the whole presentation with something like bzr (which handles binary content really well). It's worth setting up an ignore list so all the generated slides don't get versioned:

slides/*
*.cache
cache/*

Inspired by Snippy and snippits, I wrote a simple tool called snip.
It helps you to automatically fill in text for you (which can be dynamically created) and/or to perform custom keypresses and operations.


::Read more

I've been working on a cool little side project the last week called Visage. It renders graphs of collectd statistics in the browser, making the data interactive.

It's a lot more interactive than the screenshot suggests, so check out an instance of Visage running.

Some background:

collectd is an awesome way to collect statistics from your Unix machines and aggregate the stats in one place (it has a network plugin that makes this a cinch).

So you set up collectd, and you're getting all these great statistics, but you want graphs right? Graphs make the IT manager in all of us smile.

To date there have been two options for viewing graphs of collectd's data: collection.cgi, which comes bundled with collectd on most distros, though sometimes squirreled away weirdly, and the newer collection3.

The problem I have with these interfaces is that they are organised like the RRDs that collectd stores. You basically use the interface to navigate the RRDs, not deduce meaning.

I want to easily see correlations between multiple hosts during a slashdotting. I want to view related stats for a host on a dashboard page. I want to filter out datasets that aren't interesting to me.

What's holding the existing graphing interfaces back is the presentation layer (graphs generated from RRDtool, wrapped in a smattering of Perl) being very tightly coupled with the data layer (the RRDs themselves).

So I set about exposing the RRDs in a more digestible form - JSON.

Once the RRDs are exposed over the web it makes it easy to consume the data and build your own graphing interface as either a thick client, Flash widget, or in the browser. You could also do periodic snapshots and reporting, but I digress.

So once I was able to consume this data, I used the Raphaël JavaScript library to render the graphs, and turned it into a MooTools class for maximum reusability.

So there you have it!

Right now there are a few rough edges (the axis labels keep me up at night), but it's functional. If you give it a go, i'd like to know! You can report any issues you find on GitHub.

Lots of people ask me what the goal is.

The goal is for you to be able to play any song, anywhere you are, in CD quality, for less per month than the price of a cd. If you’re too cheap to pony up, then you can listen to ads instead, but no more than 10m worth for every hour you listen. A light DRM in place is fine provided the technology exists to stream this anyplace you are. Who wants or needs downloads if you can just stream it whenever you want. Disks are so overrated. If the tech isn’t there do make that happen, then screw the DRM and let those that will pirate pirate and those that will pay pay. You’ll never get them to behave otherwise anyway.

That’s the goal. First person to make it happen wins everything.

This quote was written by Tom Pepper at Nullsoft about a decade ago. Today it became a reality (give or take the ads part, in certain territories, terms and conditions apply…).

Now let’s see if they do actually win everything. They’ve got my tenner a month.

It’s a long time since I blogged about photography, but I’m coming back from 2 weeks vacation in Sicily armed with my Nikon D700, so it’s the perfect time to talk about this hobby.

Since I sold my soul to our digital overlord (and ditched my slide scanner at the same time), I now have access to all the options digital photography can give me. And one that is very cool is geotagging.

When I purchased my D700 back in last December, I had this whole geotagging idea back in my mind. Unfortunately at that time I couldn’t find any inexpensive but powerful geotagging system.

Sure you can use almost any GPS logger for this task, but the current models at that time were heavy and expensive and more directed to sports than photography.

Sure Nikon is selling the GP-1 GPS module you can attach on the camera, unfortunately it is expensive, large and doesn’t seem to be available in France.

But a couple of month ago, my father send me a link about a damn small GPS logger called: I got U GTS-120.

I got U - GTS 120

The device is just a GPS logger, it doesn’t have any display (except a blue and red led), and is not linked to the camera in anyway (it records a position every few seconds, this interval can be customized, mine is take a point every 30s).

The thing is really cool:

• it is as small as 2 (French sized) sugar cubes and weights only 20g.
• it has a large autonomy (it covered my 2 weeks vacation with intermittent usage without charging it). You can charge it connected on a computer or with any USB charger (I’m using an ipod one).
• it can capture 65000 waypoints. The frequency of acquisition can be controlled, and the 6s default one seems a little bit fast for me. I’m using comfortably 30s.
• it is cheap, about 50 EUR in France.
• it seems to work while in the pocket

The device is sold with an USB cable for charging and data access, and software. This software can be used to setup the device, display your trips, and associates photos to waypoints.

The main drawback of the system is that it is lacking a Mac OS X application. But that’s not a big deal, since there’s a GPL Mac OS X/Linux tool to download the waypoints called igotu2gpx. Once launched, this tool auto-detects the device. Then you can grab the waypoints and save them as GPX for future use.

But we’ve done only half of the way to geotagging the photos. Here comes another (free) tool: GPS Photolinker which can automatically batch geotagging tons of photos. This tool knows how to read most of the RAW photo formats, including Nikon NEF.

Geotagging is done by matching the date and time of the photo (which is stored somewhere in the EXIF data) with one of the waypoint, so it works for NEF and JPG formats.

If no waypoint date and time match, the software assigns either the closest matching waypoint (up to a configurable time difference) or a linear interpolation between two consecutive waypoint. Of course you need your camera to have an accurate date and time (mine is synchronized each time I connect it to the Nikon transfer software). GPS Photolinker is able to apply a time shift if your camera clock wasn’t accurately set. One nice feature of GPS Photolinker is that it fills the City and Country fields of the IPTC data section with Google Maps information (which seems to be accurate).

Here is a sample of my Sicily geotagging efforts in Smugmug:

Happy geotagging!

It’s a long time since I blogged about photography, but I’m coming back from 2 weeks vacation in Sicily armed with my Nikon D700, so it’s the perfect time to talk about this hobby.

Since I sold my soul to our digital overlord (and ditched my slide scanner at the same time), I now have access to all the options digital photography can give me. And one that is very cool is geotagging.

When I purchased my D700 back in last December, I had this whole geotagging idea back in my mind. Unfortunately at that time I couldn’t find any inexpensive but powerful geotagging system.

Sure you can use almost any GPS logger for this task, but the current models at that time were heavy and expensive and more directed to sports than photography.

Sure Nikon is selling the GP-1 GPS module you can attach on the camera, unfortunately it is expensive, large and doesn’t seem to be available in France.

But a couple of month ago, my father send me a link about a damn small GPS logger called: I got U GTS-120.

The device is just a GPS logger, it doesn’t have any display (except a blue and red led), and is not linked to the camera in anyway (it records a position every few seconds, this interval can be customized, mine is take a point every 30s).

The thing is really cool:

• it is as small as 2 (French sized) sugar cubes and weights only 20g.
• it has a large autonomy (it covered my 2 weeks vacation with intermittent usage without charging it). You can charge it connected on a computer or with any USB charger (I’m using an ipod one).
• it can capture 65000 waypoints. The frequency of acquisition can be controlled, and the 6s default one seems a little bit fast for me. I’m using comfortably 30s.
• it is cheap, about 50 EUR in France.
• it seems to work while in the pocket :-)

The device is sold with an USB cable for charging and data access, and software. This software can be used to setup the device, display your trips, and associates photos to waypoints.

The main drawback of the system is that it is lacking a Mac OS X application. But that’s not a big deal, since there’s a GPL Mac OS X/Linux tool to download the waypoints called igotu2gpx. Once launched, this tool auto-detects the device. Then you can grab the waypoints and save them as GPX for future use.

But we’ve done only half of the way to geotagging the photos. Here comes another (free) tool: GPS Photolinker which can automatically batch geotagging tons of photos. This tool knows how to read most of the RAW photo formats, including Nikon NEF.

Geotagging is done by matching the date and time of the photo (which is stored somewhere in the EXIF data) with one of the waypoint, so it works for NEF and JPG formats.

If no waypoint date and time match, the software assigns either the closest matching waypoint (up to a configurable time difference) or a linear interpolation between two consecutive waypoint. Of course you need your camera to have an accurate date and time (mine is synchronized each time I connect it to the Nikon transfer software). GPS Photolinker is able to apply a time shift if your camera clock wasn’t accurately set. One nice feature of GPS Photolinker is that it fills the City and Country fields of the IPTC data section with Google Maps information (which seems to be accurate).

Here is a sample of my Sicily geotagging efforts in Smugmug:

Happy geotagging!

I'm starting to keep track of some things I want. I've picked Amazon because they have many items in their database.
wishlist

The conference season is starting to warm up:

I'll be speaking at the devopsdays 2009 in Ghent, Belgium on 30th/31st of October, on cucumber-nagios and Flapjack. Patrick Debois is doing an awesome job carving out a Velocity-like conference in Europe, so if you're do any sort of operations or sysadmin work it's definitely worth attending.

In January i'll be speaking at linux.conf.au 2010 in Wellington, New Zealand on Flapjack. This year's organisers are putting together a conference so chock-full of awesome your head will be spinning. If you do anything with open source in Australia or New Zealand you can't afford to miss it.