In our office we have a Linux box, a set of speakers and a few laptops sporting Mac and Windows. Tonight I set out with a goal to turn that Linux box into an AirPlay speaker so that each of us can play music from their laptop without having to reconnect the cables every time.

Airfoil

First off I stubled upon RougeAmoeba’s Airfoil, which is a $25 sofware piece that, enables half a dozen device classes to be hooked up as remote speakers to a Mac or Windows (yes, that too). And, better yet, instead of only enabling iTunes to play, it can reroute all sound to that remote speaker. Though, it’s Linux speaker software is free download, it still seems to require paid Airfoil to route audio, because bare iTunes couldn’t care less of the wannabe Linux speaker that should have appeared to the WiFi. As the price would have been multiplied by the number of laptops, it was unfortunately out of question.

Shairport

With a bit of googling around, I next found Shairport, which (if I got it correctly) is based on data found in a hacked and reverse engineered AirPort Express. ShairPort turns a random PC into a fake AirPlay speaker set. The software itself got installed relatively quickly after going through the short docs (perhaps because I had most of the dependencies like avahi etc already in place because of the Airfoil).

Also, for Airfoil, I had already opened firewall to Zeroconf/Bonjour and ports TCP:5000-5005 and UDP:6000-6005  which seemed to apply to Shairport too.

After starting up the daemon, all of our iTunes magically discovered the new remote speakers and allowed us to play music there with a simple mouse click. Even from Windows. And from iPhone. And, if wanted, all at the same time. Voila!

This is definitely much easier than messing with the wires all the time.

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Please read all about the SOPA blackout in the Wikipedia article. I have signed a petition against SOPA and I am fully concerned about what this could mean to Internet.

Wikipedia is main source of information for me and when googling around I hit Wikipedia dozens of times a day. I would not even like to think about what it would be like if Wikipedia would be blocked, because of linking to webpages that, among other things, contained some alleged pirated materials.

Now what?

Having said all this and having already put in my 2 cents, I now have work to do and this blackout is hindering my progress, even if for just one day. Fortunately Wikipedia has not removed itself from Internet. It only has drawn a black blanket over it’s contents. So, after viewing this black page and dedicating a few (milli)seconds to think about the consequences of SOPA, tech-savvy people can still reach the articles and make use of them.

NOTE: This post is not about avoiding Wikipedia blackout. This post is about getting work done, after you have signed some anti-SOPA petition or written a letter of concern to the US Senate or your own Ministry of Foreign Affairs if you live outside US.

Desopafy

There are several ways to still access Wikipedia today. Wikipedia itself has pointed out that mobile Wikipedia is still accessible and as the blackout is JavaScript-based, disabling JavaScript, will avoid the blackout too. But being JavaScript based, the blackout can also be reversed with JS. My initial code was a bit crude, so I googled around and found a more thorough version (thanks timraymond and kballenegger). Add this link to your bookmarks (or drag it to your bookmark bar):

Desopafy_Wikipedia

This bookmarklet will hide the blackout and show the Wikipedia article. But please, do at least think of what this blackout means, before you remove it.

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The GIMP Resynthesizer plugin makes it easy to intelligently remove unwanted objects from photos. There seems to be a 2.0 version of this plugin available at the developer’s github page (bootchk/resynthesizer), but I haven’t tried that yet.

How this plugin works has been covered number of times before, (e.g this “Content-Aware Fill” clip or this resynthesizer tutorial), so I won’t go into details of this here.

Only difference for me was that I used the Enchance > Smart remove selection... filter rather than Map > Resynthesize... and the result is displayed below.

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Still, unlike Gmail, Mail.app by default shows only incoming conversation and omits sent messages, unless one presses the “Show related messages” button.

Fortunately there is a preference option to turn this on constantly.

Go to menu “Mail > Preferences > View” and check “Include related messages” box.

I wonder why this option is turned off by default?

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1. Location Aware Time Machine
2. Address Book groups

The servers:

• Passenger 3.0.8
• Unicorn 4.1.0
• Thin 1.2.11

Later I tried to test UWSGI server too as it now boasts built-in RACK module, but dropped it for two reasons: (1) it required tweaking OS to raise kern.ipc.somaxconn above 128 (which none other server needed) and later Nginx’s worker_connections above 1024 too and (2) it still lagged far behind at ~ 130 req/s, so after successful concurrency of 1000 requests, I got tired of waiting for the tests to complete and gave up seeking it’s break point. Still, UWSGI is very interesting project that I will keep my eye on, mostly because of it’s Emperor and Zerg modes and ease of deployment for dynamic mass-hosting Rack apps.

As UWSGI was originally developed for Python, I wasted a bit of time trying to get it working with some simple Python framework for comparison, but probably lack of knowledge on my part was the failure of it.

Testing

The test platform consisted of:

• MacBook Pro (dual Core i7 HT)
• Nginx 1.0.5
• JMeter 2.4

To set up a basic testcase, I wrote a simple Rack app that responds every request with the request IP address. I dediced to output IP because this involves some Ruby code in the app, but should be rather simple still.

ip = lambda do |env|
  [200, {"Content-Type" => "text/plain"}, [env["REMOTE_ADDR"]]]
end
run ip

Tweaking the concurrency number N (see below) with resolution of 100, I found out the break point of each of the servers (when they started giving errors) and recorded the previous throughput (the one that didn’t give any errors).

Results

The results are as follows:

1. Unicorn – 2451 req/s @ 1500 concurrent request
2. Thin – 2102 req/s @ 900 concurrent requests
3. Passenger – 1549 req/s @ 400 concurrent requests

The following are screenshots from JMeter results:

Unicorn @1500 concurrent request

Thin @900 concurrent requests

Passenger @400 concurrent requests

None of these throughputs are bad, but still Unicorn and Thin beat the crap out of Passenger.

Details

The JMeter testcase

1. ramp up to N requests concurrently
2. send request to the server
3. assert that response contains IP address
4. loop all of this 10 times

Nginx configuration:

    # Passenger
    server {
      listen 8080;
      server_name localhost;
      root /Users/laas/proged/rack_test/public;
      passenger_enabled on;
      rack_env production;
      passenger_min_instances 4;
    }
 
    # Unicorn
    upstream unicorn_server {
      server unix:/Users/laas/proged/rack_test/tmp/unicorn.sock fail_timeout=0;
    }
 
    server {
      listen 8081;
      server_name localhost;
      root /Users/laas/proged/rack_test/public;
 
      location / {
        proxy_pass http://unicorn_server;
      }
    }
 
    # Thin
    upstream thin_server{
      server unix:/Users/laas/proged/rack_test/tmp/thin.0.sock fail_timeout=0;
      server unix:/Users/laas/proged/rack_test/tmp/thin.1.sock fail_timeout=0;
      server unix:/Users/laas/proged/rack_test/tmp/thin.2.sock fail_timeout=0;
      server unix:/Users/laas/proged/rack_test/tmp/thin.3.sock fail_timeout=0;
    }
 
    server {
      listen 8082;
      server_name localhost;
      root /Users/laas/proged/rack_test/public;
 
      location / {
        proxy_pass http://thin_server;
      }
    }

As is only logical, having processes match the number of cores (dual HT = 4 cores) gave best results for both Thin and Unicorn (thouch the variations were small).

Unicorn configuration

Passenger requires no additional configuration and Thin was configured from command line to use 4 servers and Unix sockets, but Unicorn required a separate file (I modified Unicorn example config for my purpose):

worker_processes 4
working_directory "/Users/laas/proged/rack_test/"
listen '/Users/laas/proged/rack_test/tmp/unicorn.sock', :backlog => 512
timeout 120
pid "/Users/laas/proged/rack_test/tmp/pids/unicorn.pid"
 
preload_app true
  if GC.respond_to?(:copy_on_write_friendly=)
  GC.copy_on_write_friendly = true
end

Disclaimer

I admit that this is extremely basic test and with better configuration much can be squeezed out from all of these servers, but this simple test surved my purpose and hopefully is of help to others too.

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1. RailsVacation
2. Ruby lambda

git log --graph --full-history --all --color --date=short --pretty=format:"%x1b[31m%h%x09%x1b[0m%x20%ad%x1b[32m%d%x1b[0m %s %x1b[30m(%an)%x1b[0m"

UPDATE: I added annotation to the end of line in dark-grey (not shown in the image) so that you can blame people quicker.

This produces graph shown on the image.

GIT graph in terminal with branch names

If you noticed, I have aliased all of this for a much shorter command git tree, which can be done with the following git config line:

git config --global alias.tree 'log --graph --full-history --all --color --date=short --pretty=format:"%x1b[31m%h%x09%x1b[0m%x20%ad%x1b[32m%d%x1b[0m %s %x1b[30m(%an)%x1b[0m"'

Notice the two sets of quatation marks.

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1. RailsVacation

Simple as that.

The why

When starting something new, there is always the problem with the name. The worst part is that, most of the time, you need to come up with a name just in the middle of creation and when you least know, whether the beast will walk, swim or fly. And the name sticks. And sometimes the name stinks too. After some initial moments, I never really liked the name Brolog (being not-so-clever wordplay on Prolog and Blog). Given that I have never actually seen Prolog in action and know nothing of the language it seemed a bit false. So today I woke up and had a new name, that relates more to what I do daily – commit to GIT. Or write to commitlog if you will.

So. There you have it. CommitBlog.

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This is a script to merge SVG files with CSV data-files using Inkscape, to produce one outputfile (e.g. PDF) per data-row.

Script inspired by and based on Aurélio A. Heckert excellent InkscapeGenerator (wiki.colivre.net/Aurium/InkscapeGenerator)

Heckert’s original script unfortunately broke for me several times and I took the opportunity to rewrite it and make it more extendable for future.

USAGE

Install the gem

gem install inkscape_merge

Create files

Create CSV data file with first row as a header. The values from this row are used as keys in the SVG file substitution.

Create SVG file that contains some variables in the form:

%VAR_name%

Where `name` is the name of a column in the CSV file created previously. These variables can be anywhere inside the SVG, from plain text nodes to color values. This script just brute-forcedly `gsubs` these values as text w/o any thought.

Run the script

The script requires at least three arguments:

• the input SVG file
• the input CSV file
• and the output file `pattern`

Note: output pattern undergoes the same substitutions as the SVG file, so to create easily unique file names. Additionally the output pattern can contain `%d` which is replaced with current row number.

Example:

inkscape_merge -f postcard.svg -d names.csv -o postcards/card_%d.pdf

This produces files like:

• postcards/
  • card_1.pdf
  • card_2.pdf

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This forum listed one of them that got it working for me - macfuse-core-10.5-2.1.9.dmg.

Though, pardsbane here tells of another project – OSXFUSE – one the way that will support Lion out of the box (when the box is released).

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Say, for example, that you have in your apache conf the following lines:

  DocumentRoot /var/www/htdocs
  Alias /phpsite /var/www/mysite

That means that your PHP site resides in /var/www/mysite, while rest of your web resides in /var/www/htdocs. How will your PHP scripts know that /phpsite portion, without hardcoding this into scripts, when they do not know how many levels deep in directory structure they themselves are in your site (e.g /phpsite/posts/update.php).

First, if you already don’t have, create a script (call it what ever you like, e.g. config.php) somewhere in your site folder. Preferred is at the top level, but subfolders work too (more on this later).

Secondly, put the following inside that file:

$wwwroot = "http://" . $_SERVER['SERVER_NAME'] .
      str_replace(
        str_replace(
          dirname(__FILE__),
          "",
          $_SERVER['SCRIPT_FILENAME']),
        "",
        $_SERVER['SCRIPT_NAME']);

If you placed your config.php in some subfolder, then you have to multiply the dirname() calls for every subfolder level. E.g if your config.php is in conf/config.php, i.e second level, you need 2 dirname() calls and your 4th line should look like:

dirname(dirname(__FILE__))

Third, include this file in every script, even in subfolders and prepend to links:

require_once "../config.php";
echo "<a href="$wwwroot/some/script.php">Some script</a>";

Voila!

Under the hood

What this script does is actually rather simple string algebra. The contents of those special variable is as follows:

$_SERVER['SERVER_NAME']
    # => example.com
__FILE__
    # => /var/www/mysite/config.php - the name of the script where this is written
$_SERVER['SCRIPT_FILENAME']
    # => /var/www/mysite/dir/script.php - the full path to script that included config.php
$_SERVER['SCRIPT_NAME']
    # => /phpsite/dir/script.php - the URL path of the script that included config.php

You might already start to grasp what we’re about to do. Leaving aside the obvious hostname part, what the str_replace part does is the following:

1. calculate filesystem path to the base of the site: dirname(__FILE__): /var/www/mysite/config.php => /var/www/mysite
2. substract this path from the SCRIPT_FILENAME => /var/www/mysite/dir/script.php => /dir/script.php
3. substract the result from the URL SCRIPT_NAME => /phpsite/dir/script.php => /phpsite

This method works even if you change the Alias or remove it altogether.

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