Introduction to Programming: What I wish I knew

Every Introduction to Programming class starts with a programming language, introduces various concepts like variables and functions and leaves with an understanding of some simple algorithms. Mine was no different. We used C and spent a lot of time trying to make students comfortable using Linux. This leaves a lot to be desired. Software engineering is hard and laying out certain principles at the beginning can help tremendously. This is a short list of supplemental resources I would have liked to have when I started programming.

Understanding Ansible and Jinja2's default() filter

I have been using Ansible at work for the past month to set up some infrastructure. I wanted to express the following in the setup script: ansible_ssh_user: "{{ lookup('env', 'SSH_USER') }}" but wanted to set the user to ubuntu if SSH_USER was not set. For some reason, this would not work: ansible_ssh_user: "{{ lookup('env', 'SSH_USER') | default('ubuntu') }}" Ansible provides several functions that can extract various string values from the environment.

Linux Application Container Fundamentals

At my current job, I spend a lot of time coaxing Docker to run containers while trying to avoid network failures, Docker bugs and kernel reference count issues. Recently, I’ve gotten into reading about how Docker and other containerization software is implemented under the hood. This is a write-up of my exploration and experiments looking at how container runtimes are implemented. Nothing in this essay is original, but I hope it helps some people.

Writing a simple database in rust, part 1

A Simple and Efficient Implementation for Small Databases is an old paper that I've wanted to implement for a long time. It describes a simple application that embodies a lot of "systems" knowledge at the same time: Using the filesystem as a persistence and synchronization mechanism.Using a write-ahead log as a source of truth.Creating crash tolerant (or crash-only) systems.While ideally you'd want to write this in C or C++, mucking around with strings and files isn't a very pleasant experience unless you are willing to pull in some third party libraries.

Banner Peak

Note: Image titles can be viewed by hovering over the image. My interest in Banner Peak and Mt. Ritter began when I encountered them while hiking the John Muir Trail in August 2014. Immortalized by Ansel Adams, the 2 mountains framed by Garnet Lake and Thousand Island Lake are well known and frequently climbed. I snagged permits for Ediza Lake several months ago, with an intention to climb both Ritter and Banner via their scrambling routes from the Ritter/Banner saddle.

Getting Vidyo running on Archlinux & Plasma 5

I recently upgraded to Plasma 5.2 based upon this glowing review. While the transition was smooth for the most part (apart from minor KWin issues), Vidyo started to segfault. The Plasma system tray no longer supports older system tray protocols. I'm not aware of the details, but VidyoDesktop would complain about not being able to set a system tray icon and segfault. The fix is to install the sni-qt package from the extra repository.

ServiceWorkers in Firefox Update: July 26, 2014

(I will be on vacation July 27 to August 18 and unable to reply to any comments. Please see the end of the post for other ways to ask questions and raise issues.) It’s been over 2 months since my last post, so here is an update. But first, a link to a latest build (and this time it won’t expire!). For instructions on enabling all the APIs, see the earlier post.

ServiceWorker implementation status in Firefox

ServiceWorkers are a new web platform feature that allows sites to use JavaScript to provide a better offline experience, and eventually various other 'background service' capabilities. Jake Archibald has a good article on his blog explaining them further. I've been working on the Gecko implementation for a while now, helped by several other Mozillians and some of the first patches are now beginning to land on Nightly. Interest in trying out a build has been high within both Mozilla and outside.

Trip Report: Canyonlands Backpacking and Packrafting

Lacking in pictures because even in 2014, embedding images from alternate sources in a blog post is ridiculous UX fail! In March (19-25), Raj, Michaela, Roxana and I went on a 6 day trip to Utah. The itinerary was to fly into Salt Lake City, drive to Moab, do a 4 day backpacking and packrafting trip in Canyonlands NP, spend a day in Arches NP and head back. It was one of the best trips I’ve done and a splendid (and early!) start to this year’s trips.