Sean Santry's Development Blog

Fixing “MAC address could not be autodected” error from UUIDTools, Phusion Passenger and Ruby Enterprise Edition

2008-08-29T00:00:00-04:00

I’m using the UUIDTools 1.0.3 gem in a Rails 2.1 application to generate globally unique IDs. After migrating the site to run under Phusion Passenger and Ruby Enterprise Edition I began encountering the following error:

StandardError (MAC address could not be autodetected.  Set the MAC address manually.):
    /vendor/gems/uuidtools-1.0.3/lib/uuidtools.rb:241:in `timestamp_create'
    /vendor/gems/uuidtools-1.0.3/lib/uuidtools.rb:229:in `synchronize'
    /vendor/gems/uuidtools-1.0.3/lib/uuidtools.rb:229:in `timestamp_create'
    ...

It seemed UUIDTools was trying to get the the network card’s MAC address (I’d guess to collect entropy), but couldn’t for some reason. I should also note that this is all running on an Ubuntu Hardy Heron 8.04, 512MB slice over at Slicehost (yes, that’s a referral link, use it! :-).

It turns out that UUIDTools was trying to use ifconfig to read the MAC address, but ifconfig wasn’t in the PATH. Since the application is now running under mod_rails, the relevant PATH is Apache’s PATH, which doesn’t include /sbin by default.

So, a quick edit of /etc/init.d/apache2 to change

ENV="env -i LANG=C PATH=/usr/local/bin:/usr/bin:/bin"

ENV="env -i LANG=C PATH=/usr/local/bin:/usr/bin:/bin:/sbin"

and a sudo /etc/init.d/apache2 restart was all it took to get the app back up and running.

GitHub Invite Giveaway

2008-04-07T00:00:00-04:00

I’ve got a few GitHub invites available if anyone is interested. I’ve started putting a few of my open-source projects up there as well and so far it seems pretty cool.

Email link is in the footer, so come and get ‘em!

Update to EnkoderTags Radiant Extension

2008-03-16T00:00:00-04:00

I’ve updated EnkoderTags to allow HTML attributes in the enkode_mailto tag. The attributes will get passed through untouched into the resulting markup, so you can add CSS classes or IDs to use as styling hooks. For example, this code

<r:enkode_mailto email="example@example.com" link_text="simple email example"
    class="enkodedlink"/>

will produce the HTML

<a href="mailto:example@example.com" class="enkodedlink">simple email example</a>

which will be obfuscated through the Enkoder as usual. Thanks to Nick Calladine for prompting me to add this feature!

Git Repositories for Rails Plugins

2008-02-09T00:00:00-05:00

Having moved to git for managing my Rails projects and git submodules for Rails plugins and vendor/rails, I decided to create git mirrors for a couple of plugins whose maintainers use subversion.

has_many_polymorphs (git://repo.or.cz/has_many_polymorphs.git)
acts_as_ferret (git://repo.or.cz/acts_as_ferret.git)

If you have a Rails project in a git repository, you might do

git submodule add git://repo.or.cz/has\_many\_polymorphs.git vendor/plugins/has\_many\_polymorphs
git submodule add git://repo.or.cz/acts\_as\_ferret.git vendor/plugins/acts\_as\_ferret

and perhaps

git submodule add git://git.sanityinc.com/rails.git vendor/rails

followed by

git submodule init
git submodule update

Building Git 1.5.4 on Mac OS X 10.5 Leopard

2008-02-02T00:00:00-05:00

Wincent Colaiuta has some good, basic instructions for getting Git version 1.5.3.x built and installed on Mac OS X Leopard.

For Git 1.5.4, building git-gui will fail when it tries to build some localization files. The message I got during make prefix=/usr/local all was

    GITGUI_VERSION = 0.9.2
    * new locations or Tcl/Tk interpreter
    GEN git-gui
    INDEX lib/
    MSGFMT    po/de.msg 371 translated.
    MSGFMT    po/fr.msg 371 translated.
    MSGFMT    po/hu.msg 371 translated.
    MSGFMT    po/it.msg 370 translated, 1 untranslated.
    MSGFMT    po/ja.msg 371 translated.
    MSGFMT    po/ru.msg 367 translated, 4 untranslated.
    MSGFMT    po/sv.msg 371 translated.
    MSGFMT po/zh_cn.msg 53 translated, 57 fuzzy, 253 untranslated.
    SUBDIR gitk-git
    GEN gitk-wish
Generating catalog po/de.msg
msgfmt --statistics --tcl po/de.po -l de -d po/
make[1]: msgfmt: Command not found
make[1]: *** [po/de.msg] Error 127
make: *** [all] Error 2

This is because Leopard doesn’t come with the GNU gettext utilities. While I imagine one could build and install gettext, there’s an easier fix. Just set the NO_MSGFMT environment variable to yes and the Git build scripts will use a simple (well, according to the source, “really stupid”) program that does the necessary work in place of gettext’s msgfmt tool.

So, just tack NO_MSGFMT=yes in front of your build and you’re all set.

NO_MSGFMT=yes make prefix=/usr/local all

How Many Can You Name?

2007-11-28T00:00:00-05:00

I have no idea how I can remember input but forget form…

Radiant Extensions for Blogging, Flickr and Spam Prevention

2007-04-19T00:00:00-04:00

I’ve updated my Radiant plugins for Radiant 0.6’s new extension mechanism. I’ll package up proper releases soon, but in the meantime you can get them from my Subversion repository. If you’ve checked out the Radiant mental branch, svn:externals is the way to go:

cd /path/to/radiant
svn propedit svn:externals vendor/extensions

Then add the following three lines and save

blog_tags http://seansantry.com/svn/radiant/extensions/blogtags/trunk
enkoder_tags http://seansantry.com/svn/radiant/extensions/enkodertags/trunk
flickr_tags http://seansantry.com/svn/radiant/extensions/flickrtags/trunk

Follow that with an svn update vendor/extensions and you’re all set. If you’re running the gem you can go into your vendor/extensions directory and export the extensions from Subversion:

svn export http://seansantry.com/svn/radiant/extensions/blogtags/trunk blog_tags
svn export http://seansantry.com/svn/radiant/extensions/enkodertags/trunk enkoder_tags
svn export http://seansantry.com/svn/radiant/extensions/flickrtags/trunk flickr_tags

Creating an Atom Feed in Radiant

2006-12-15T00:00:00-05:00

Updated: I’ve updated the code to use Radiant 0.6’s <r:date for="updated_at"/> to get the last updated dates right for the feed and its articles.

Out of the box, Radiant and its sample blog templates include an RSS feed. Having recently taken an interest in Atom I thought I’d try building an Atom feed. Here’s how I did it.

Atom Requirements

Creating the Atom feed itself is fairly straightforward, but there are a few things to be aware of.

Atom feeds use the application/atom+xml Content-Type so the first step is to create an appropriate Layout. [Note: To edit the layout’s Content-Type click the More link that appears under the Name field.]

The feed and its entries each require an id element. There are many possible schemes for ids but I’ve chosen URLs to keep things simple. Also, the feed has an updated element to indicate when the feed was last updated. Finally, all timestamps in the feed must conform to RFC 3339.

Building the Feed

The beginning of the feed is quite simple. The root is a feed element in the Atom namespace. There’s a title element and separate link elements for links to the feed itself and to the page associated with the feed (in this case, my home page). The generator element indicates that the feed was created using Radiant.

<?xml version="1.0" encoding="UTF-8"?>
<feed xmlns="http://www.w3.org/2005/Atom" xml:lang="en-us">

  <title type="text">Sean Santry</title>

  <link rel="self" href="http://seansantry.com<r:url />" />
  <link rel="alternate" type="text/html" href="http://seansantry.com/" />

  <id>http://seansantry.com/</id>

  <generator uri="http://radiantcms.org/" 
    version="0.5.2">Radiant CMS</generator>

Next is the author element with my name and the uri for my site. An email element is optional (for feeding spammers).

  <author>
    <name>Sean Santry</name>
    <uri>http://seansantry.com/</uri>
  </author>

I mentioned that the feed has an updated element with a timestamp that indicates when the feed was last updated. Since this timestamp depends on when an entry was most recently added or modified Radiant’s r:date tag won’t work. That would give the date when the Atom feed itself was last edited, which isn’t correct.

The solution is to find the most recent article using a combination of Radiant tags. The r:find tag gets all the articles in my blog and the r:children:each tag sorts by the published_at date in descending order. Setting the limit attribute to 1 gets back just the most recently updated page. Finally the r:date tag with the RFC 3339 date format (%Y-%m-%dT%H:%M:%SZ) populates the feed’s updated element.

  <updated><r:find url="/articles/">
    <r:children:each limit="1" order="desc">
      <r:date format="%Y-%m-%dT%H:%M:%SZ" for="updated_at" />
    </r:children:each>
  </r:find></updated>

Adding the entries themselves is simple. Once again the r:find and r:children:each tags get the appropriate pages. Within the entry element are the entry’s author, the dates on which the entry was last published and updated and the entry’s title. The entry’s URL serves as the entry’s id and as the entry’s permalink (in the link element).

I like providing the full content for entries in my feeds, so the content element has the full output from the r:content tag. If your entries have summaries stored in a page part, you could use that instead.

  <r:find url="/articles/">
  <r:children:each limit="10" order="desc">
    <entry>
      <author><name><r:author /></name></author>
      <published><r:date format="%Y-%m-%dT%H:%M:%SZ" /></published>
      <updated><r:date format="%Y-%m-%dT%H:%M:%SZ" for="updated_at" /></updated>
      <title><r:title /></title>
      <link rel="alternate" type="text/html" 
        href="http://seansantry.com<r:url />" />
      <id>http://seansantry.com<r:url /></id>
      <content type="html"><r:escape_html>
        <r:content /></r:escape_html></content>
    </entry>
  </r:children:each>
  </r:find>

</feed>

You can see the results of this feed at http://seansantry.com/atom/. Download the source to get started. Once you’ve created your feed you can check it for validity using the feed validator.

Radiant Plugins

2006-11-01T00:00:00-05:00

I’ve cobbled together a few Radiant plugins for my site and thought others might find them useful.

BlogTags provides next and previous tags for linking to the next and previous articles in your blog. These are based on some code John Long posted to the Radiant mailing list. You can see them in action at the end of this article. This plugin also provides a time_ago_in_words tag to output the page’s published_at date in words (eg, “3 days ago”).
EnkoderTags provides tags to help prevent spammers harvesting email addresses from your site. It’s a simple refactoring of Dan Benjamin’s Hivelogic Enkoder. I’m using this plugin to enkode email addresses shown on this site.
FlickrTags is in the very early stages of development. Right now the only really useful tag is slideshow, which embeds a Flickr slideshow in an iframe. You can see an example in my portfolio. I’m working on integrating Scott Raymond’s Flickr API for more advanced functionality.

These plugins are available from my subversion repository. To install, simply export any one of the plugins into your Radiant installation’s vendor/plugins folder. For example:

svn export http://seansantry.com/svn/radiant/plugins/blogtags/trunk \
    /path/to/radiant/vendor/plugins/00_blogtags

Note that you should prefix the target directory with 00_ to ensure that these plugins are loaded before others. Otherwise the global tags these plugins define won’t be available in pages that use behaviors.

Cheap Storage

2005-12-21T00:00:00-05:00

$1.98? That seems pretty cheap. Isn’t that what a gallon of gas costs these days?

Oh, $1.9B as in Billion. That makes more sense.