splapr: Modular, Customizable and Affordable Split-flap Displays for Everyone

I have always been fascinated by split-flap displays and for years I have wanted to make some myself. Today, I’m releasing my most recent effort to make split flap displays accessible to everyone.

To find out more, visit https://splapr.com

module front face

makes me grin everytime

WireGuard VPN on Android

My recent experience with Telstra mobile’s DNS resolver constantly pooping itself, leaving me without working 4G connection on my Pixel 2 Android phone, prompted me to look for solutions. How do I know it was the DNS resolver issue? Well I got myself a ping tool and found that I could ping various servers just fine. I did try the Private DNS feature of Android to no avail. Most of the time it doesn’t do anything!

Unfortunately, Android doesn’t allow manually setting DNS on mobile connection (only on WiFi and VPN). So the only option I had left was to look at VPN tunnels. Forget about OpenVPN and IPSEC. For my use case, they were mind numbingly difficult to setup and I gave up on both very quickly. Then I remembered WireGuard, a tiny feature of Linux kernel brewing at the moment, which lets you define an encrypted network interface with public key cryptography. There is also an app available for Android. This thing is so simple to setup and so reliable that I was hooked right off the bat.

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An Incident Post-mortem

I was involved in an incident post-mortem today without realizing it! But first, a little background.

I lead the Incident Response team at Mathspace and we follow a blameless post-mortem culture as popularized by SREs. It boils down to not blaming specific person(s) seemingly responsible for an incident, but instead acknowledging that incidents are product of failure at team/org level. We then focus our efforts to pinpoint root cause and ways of preventing it from happening in the future.

Today’s post-mortem was outside of work! I had just met up with my partner at a cafe and we were walking home when she told me about her experience riding her usual bus back from work. The bus doors had barely finished closing behind her, when the driver stepped on the accelerator like it was race car. As she had not yet tightened her grip on the rails, she almost fell to the floor had it not been for assistance from another passenger on the first row. She was quite upset while telling the story. In fact, it was such a distressing event for her, that she took the time to report this driver to the authorities. That marked the end of her story.

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HTTP health check endpoint using socat

What do you do when you need to expose an HTTP health check endpoint but the thing you’re health checking isn’t a web server? You socat it! Here’s a complete example:

nohup socat TCP-LISTEN:8080,reuseaddr,fork,crnl SYSTEM:"
  supervisorctl status celery | grep -q RUNNING &&
    echo HTTP/1.0 200 OK ||
    echo HTTP/1.0 500 Down
" &>/dev/null &

In short, the above will run a web server on port 8080 which will respond with HTTP status code of 200 if celery is running, or 500 otherwise. You can replace supervisorctl status celery | grep -q RUNNING with any other command. The exit code of that command determines the web server’s response. Pretty neat ha!

Non-permanent Actions

We make mistakes. In most part of life, mistakes tend to incur cost, from money, harm to simply time, and due to interaction with the physical world. In world of software however, where state of things can be cheaply changed back and forth, with some clever design, mistakes can be made free of cost. I’ve increasingly noticed more of such design in products I use and I thought I make a list here:

Mute notifications for next 4 hours. Notifications can sometimes frustrate the user who is under stress and if the notification settings stick indefinitely, a temporary annoyance can turn to ignored messages/emails for days. Google Hangouts, Slack and most messaging apps have timed mute feature. One place where this is very much needed is on browsers. Given that browser is a platform, it relieves all the individual sites from having to implement this functionality. Android is a good example where this is implemented across the entire OS. It even goes further and allows marking notifications from certain apps as being of higher priority which bypass the mute period.

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You called it an adventure
Showed me a pretty picture
with a wide aperture
You commanded that I follow closely
after your vertically descending departure

I leaped after a bunny
when it was no longer sunny
Now I think of it as funny
how I landed in a jar of honey

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Midnight Groove

Your wall mirror was dressed
in midnight summer breeze
I slowly walked in front of it
with an attitude and a tease

She offered her hand for a dance
You were deftly asleep that night
So she and I fell into a deep groove
And moved as one till the morning light

Visual Beep

The quieter you become, the more you hear.

I was hanging in the local IKEA store when I came across this $5 multifunction digital clock. The interesting thing about it is that you switch between the functions, not by pressing a button, but by turning the clock on its various sides. It has four sides and hence four functions: thermometer, alarm, clock and countdown timer. The countdown timer in particular is awesome. You set the timer and every time you turn the clock on the timer side, it automatically starts counting down.

IKEA desktop clock/thermometer/alarm/timer

It comes under two names: LÖTTORP and KLOCKIS

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Three way

Twelve stories tall
Waiting for a call
Watching city porn
Groping the glass wall

Seismic handshake by the lake
Bear hug soothing the hand ache
Fresh lime with a slice of cake
Conversing for hours without a break

Turning down the volume
Leaning in to consume
the air of your perfume
Feelings to exhume

systemd-nspawn based dev environment

Over the last week, I decided to move my dev environment from OSX to my own Archlinux box. Now I didn’t want to pollute my machine with various libraries/tools needed for work so I decided to run things in a container. I had played with systemd-nspawn in the past so it was the clear first choice (and last in this case). Overall I am very happy with it as it was a piece of cake to setup and only one or two hiccups along the way.

I followed the excellent guide on Archlinux Wiki and that took me 95% of the way. Firefox tweaks page took me 99% there. What follows are some tips for the last mile.

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