HMAC SHA256 signatures in Python and Flask.

November 6, 2019. Filed under python 56slack 6

I'm playing around a bit with the [Slack API](, which I'll have a longer post on in a bit. One part of the integration requires generating a HMAC SHA256 signature to verify requests are from Slack. There weren't too many helpful rearch results, so I've written up a concise example.

Forecasting synthetic metrics.

November 5, 2019. Filed under infrastructure 30metrics 4reliability 2

Imagine you woke up one day and found yourself responsible for a Site Reliability Engineering team. By 10AM, you’ve downloaded a free copy the SRE book, and are starting to get the hang of things. Then an incident strikes: oh no! Folks rally to mitigate user impact and later diagnosis and remediate the underlying cause, but a bunch of your users have a very bad day. Your shoulders are a bit heavier than just a few hours ago. You sit down with your team and declare your bold leader-y goal: next quarter we’ll have _zero_ _incidents_.

Sending weekly 5-15 updates.

November 3, 2019. Filed under management 86

About a year ago I started sending public weekly updates to a relevant public (within the company) mailing list. I've found the practice useful enough to write a few works on the how and why. This practice is sometimes called a 5-15 report reflecting the goal of spending fifteen minutes a week writing a report that can be read in five minutes.

Investing in technical infrastructure @ SRECon EMEA 2019

October 31, 2019. Filed under infrastructure 30speaking 6talks 6

A few weeks ago I got the chance to speak at SRECon EMEA 2019, and the videos are up! This is the video of my talk, Investing in technical infrastructure.

Healthchecks at scale.

October 27, 2019. Filed under infrastructure 30architecture 25

A couple days ago at Stripe's weekly incident review, we started a discussion on a topic that is always surprisingly controversial: healthchecks. I've been thinking about them since and have written up some related thoughts.