duncanlock.net

This site has been generated using Pelican 3.3 for over two years - and I finally found some time to upgrade to the current version of Pelican, 3.6.3. This is how I did the upgrade.

I decided to be lazy and do the upgrade in-place, instead of creating a new virtualenv and copying the content & settings over. Luckily, this worked out OK, after a bit of fiddling around.

I also decided, rather cavalierly, to upgrade all the packages in the virtualenv to their latest versions while I was at it. To do this, I upgraded pip, then used pip-review. To upgrade pip & install pip-review system wide, run this on the command line:

$ sudo -H pip install --upgrade pip
$ sudo -H pip install pip-review

Then upgrade eveything in the sites virtualenv:

$ sudo apt-get install libjpeg-dev
$ workon duncanlock.net
$ pip-review …
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We use CentOS VMs at work to emulate our production environment - and it took me a while to figure out how to get the VirtualBox Guest Additions to build reliably on CentOS 6.4/5. This is what I’ve currently settled on as a reliable method.

First, make sure that you’ve got the kernel headers and tools installed that you need to build stuff:

$ sudo yum update -y
$ sudo yum install gcc kernel-devel kernel-headers dkms make bzip2 perl

Make sure that you’ve only got the current set of kernel headers installed - the one for the kernel you’re actually running. Having more than one set installed prevents this working properly. Running this should show you one version of each kernel package:

$ rpm -qa | grep kernel | sort

It should look something like this:

dracut-kernel-004-336.el6_5.2.noarch
kernel-2 …
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IMG 20131119 095456 small
Figure 1. Taken from my Wife’s office window, around 10am.

The weather was great this week - crisp and autumnal, with beautiful sunshine all week. It snowed a little on the local mountains and Cypress Mountain has opened for (limited) Skiing already, using the lower temperatures to make lots of extra snow. Whistler also opened this week, along with Grouse.

IMG 20131119 161127 small
Figure 2. Taken from my Wife’s office window in the afternoon, during the Golden Hour, which is now around 4pm.

In other, even better news, I’m starting a fantastic new job with PHEMI Health Systems on Monday - allowing me to afford to actually go skiing. I’ll be working as a front-end web developer, helping to build their healthcare information system, directly helping to improve clinical productivity, patient outcomes and medical research. Very excited to be using my …

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To create image thumbnails from a PDF document, run this in a terminal window:

$ convert -thumbnail x300 -background white -alpha remove input_file.pdf[0] output_thumbnail.png

The parameters to convert do the following things:

ParameterEffect
-thumbnailSimilar to -resize, but optimized for speed and strips metadata.
x300Make the thumbnail 300px tall, and whatever width maintains the aspect ratio.
-background whiteSets the thumbnail background to white.
-alpha removeRemoves the alpha channel from the thumbnail output.
input_file.pdfThe PDF file to use as input.
[0]The page number of the input file to use for the thumbnail.
output_thumbnail.pngThe output thumbnail file to create.

If you want larger thumbnails, just change the x300 parameter to match. If you want to output .jpg’s (or anything else, like .gif), just change the file extension on the output_thumbnail …

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A dummy placeholder image
Figure 1. This figure has automatic figure numbering.

I had a feature request for automatic figure numbering, like latex. I was revamping this plugin for Pelican 3.3 anyway - and this didn’t seem too hard - so I decided to add it.

So, the Better Figures & Images plugin now supports automatic figure numbering. To enable this for all posts, just add this to your config file:

FIGURE_NUMBERS = True

If you want to enable this per post, just add this to the metadata at the top of the post:

for restructuredText add this:

:figure_numbers: true

and for Markdown add this:

figure_numbers: true
Caution:

Can you have Figures in Markdown?

I use reStructuredText for this site, and I’m not sure if you can even have Figures in Markdown documents - and I haven’t tested it, so caveat emptor.

It adds this …

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There are quite a few changes in Pelican 3.3 - most of them minor, but a few which might mean making some changes to your site in order to upgrade. This is what I did to move my site from Pelican 3.2 to 3.3.

The change that had the biggest impact and took the most work was around image linking - caused by a combination of things. I think I was doing it wrong before and things changed in a way that meant this no longer worked. I also had to update my Better Figures & Images plugin to take this into account.

Previously, I’d been linking to my images like this, both in my theme:

/* Theme CSS Image Link */
background: #2C71B8 url(/static/images/blueprint-background.png) repeat;
{# Theme HTML/Jinja image link #}
<meta name="twitter:image" content …
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Flag of Brazil

I’ve recently been corresponding with Denny Dias, from Brazil, who’s converted his blog over to Pelican - and we’ve been helping each other out a bit with building themes and whatnot.

He’s written up his conversion & theme building process - and was generous enough to credit me after he borrowed some of my theme’s logic, from this blog’s GitHub repo.

As he’s such a nice guy - and as I’ve just borrowed his tagsort jinja filter for my blog’s tag page, I though I’d return the favour - cheers Deny! :)

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I’m going to build on Jamie Zawinski’s excellent advice about backups, which you should read first. This is basically that, but with some extra bits. If this seems too complex, then just do what he says.

The plan is to use Backupninja to backup everything to an external USB drive – and also to Amazon S3 or Dropbox, depending on what it is. Backupninja provides a centralized way to configure and schedule many different backup utilities, just by dropping a few simple configuration files into /etc/backup.d/.

I have a multiple hard disk setup for my desktop Linux box - my /home folders live on one disk and / lives on another one. I don’t want to backup everything from the system disk - I can re-install it in 10 mins, and I don’t really want to complicate this …

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I recently needed to convert some FLAC music files from the increasingly common 48 bit encoding, down to 16 bit at 44100 kHz, so that they’ll play on my Sonos. Here’s how to do it:

If you don’t already have sox installed, do this to install it:

$ sudo apt-get install sox

Then run this to do the conversion, in the folder with music in:

$ mkdir resampled
$ for flac in *.flac; do sox -S "${flac}" -r 44100 -b 16 ./resampled/"${flac}"; done

And that’s it - it will convert all the .flac files in that folder to 16 bit at 44100 kHz and put the result into the ./resampled subfolder, preserving the metadata.

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A trip report from our Canada Day 2013 long weekend kayak camping trip to Thormanby Islands, Smuggler Cove & Secret Cove, on the sunshine coast.

thormanby trip map
Figure 1. We started at Welcome Beach on Saturday afternoon, kayaked over to Thormanby for lunch, then up and round to Buccaneer Bay - stunning camp on the dunes, then over to Smugglers Cove on Sunday. Camped there Sunday night, with a trip to Secret Cove in the afternoon, then back to Welcome Beach on Monday morning. (Map screenshot courtesy and copyright Google Maps. Annotations added by me.)

Welcome Beach to Thormanby

On Saturday morning, we packed up our tent & got picked up by Erika from Talaysay Tours, who drove us, with the Kayak on the roof, to Welcome Beach, about 15 mins further up Highway 101, past Sechelt.

We unloaded the Kayak, took it down to …

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