Heartbleed Defeated

For those of…

prox part 3 — effect abstraction and ZIO

Intro The first post introduced the prox library and demonstrated the advanced type level programming techniques it uses. Then in the second part of this series, we experimented with replacing the streaming library from fs2 to Akka Streams. In both cases, the library used cats-effect for describing side effects. But it…

My Three Days at Craft 2014

Honest Deadlines

Rendering: don’t try this at Chrome!

If, like me, you’re writing a graphics intensive web application that renders on Canvas, you may, with some justification, have thought that the era of cross-browser compatibility issues (and the inevitable accompanying hacks) was over. Well, here at Prezi, we’re working on a player to use Javascript and Canvas2D, and…

Prezi Got Pwned: A Tale of Responsible Disclosure

The emails that arrive in a security engineer’s inbox can be put into three broad categories. 1) Readable Details of a new Budapest craft beer bar Links to articles about actual real-life hoverboards…

The Future of JavaScript

Startups identify with JavaScript. When you’re just starting out, you need to be dynamic. You need to be flexible. You need to be able to bust out a…

prox part 2 — akka streams with cats effect

Intro In the previous post, we have seen how prox applies advanced type level programming techniques to express executing external system processes. The input and output of these processes can be connected to streams. The current version of prox uses the fs2 library to describe these streams, and cats-effect as an…

For Our Daughters

Eszti The obvious answer is a shallow one: I have a two-year-old daughter and I want her to grow up in a world where…

In search of speed — debugging Elasticsearch performance

Background Here at Prezi, we use Elasticsearch to power the Explore pages for both Prezi Presentations and Prezi Videos. At the start of this year, we started running into performance issues with our cluster. Queries would take too long, some would timeout, resulting in 500 errors, high latency, degraded user experience…

Performance Monitoring With Speedprobe

In the DevOps community, we all share common enemies: the insidious complexities of building and operating applications, the all-too reasonable, yet high expectation that users have for that application’s performance, and the scarcity of hours in the day. Time may be money, but it’s also our time, and the happiness…

How Prezi switched data centers on the fly

The pit crew can change the tires on a racecar in 12–14 seconds[1]. That’s insanely fast compared to the 29 minutes, bruised fingers, and oil stained pants that it took me to do the same thing with our family car, but the difference is quantitative, not qualitative. Every single tire…

Short-Lived Functional Teams Work — or — the QA SWAT Team

Functional teams have gotten a bad reputation in the startup community. There is no dearth of job listings for full stack engineers, or blog posts about the virtues of the DevOps movement. The consensus is that we shouldn’t partition expertise in a single team, and we shouldn’t restrict responsibility to…

Changelog: A Tool Designed to Help You Recover Faster

Image via AndroidPolice When (not if) things break, it’s important to…

A Kubernetes crime story

The problem with having a great monitoring system is that you notice problems you couldn’t notice before. This is exactly what happened to us when we migrated our Nginx based reverse proxy to Kubernetes: we noticed that tail latency (p99) got somewhat higher for a few of our services. Increased p99 latencies start on 7/24 In…

Evolution of Data Ingestion and Product Instrumentation at Prezi

In this talk, we will cover how we took our need to better understand how our users use our product and how we ended up designing a system for product instrumentation and event processing to get those insights. Even though this does not sound hard, we were not as successful as we’d like to be at first. Thus we redesigned our data ingestion pipeline a couple of times to get to the state where we are today. We will start by covering how our data ingestion pipeline evolved, from starting with semi-structured event data copied to S3 with a bash script, to using Avro with Confluent schema registry ingesting events from Apache Kafka with Apache Gobblin to S3. Even though Apache Kafka helps a lot in scaling, just using Kafka alone is not your silver bullet. We had to introduce multiple components like using Avro format and the schema registry to solve for the missing pieces. We will also cover how we built around this ecosystem to make sure our system is foolproof; make it less painful to instrument the right events; and define how instrumentation works across the various platforms we support (Mac, Windows, iOS, Android, Web). Lastly, we will cover how this framework allows us to move faster, by benefiting data science projects and self-service analytics in general.

Oh Android, we’re like so future.

Bond had been waiting for Prezi for Android for quite some time. Well, there are two answers. 1. The huge problem that’s always there:

Prometheus Unchained

A big shout-out is due to David Guerrero who did…

prox part 1 — type level programming in Scala

Intro I started writing prox at the end of 2017 for two reasons. First, I never liked any of the existing solutions for running external processes and capture their input/output streams. And I just returned from the scala.io conference full of inspiration; I wanted to try out some techniques and libraries…

Simpler Management of Modular App Development

This is…

Reactive Swift

UPDATE: ReactiveCocoa‘s new Swift API is out now. You can find my new post about how I upgraded this iOS app with the latest ReactiveCocoa on All The Flow blog. Reactive Swift: upgrading to ReactiveCocoa 3.0 If the title doesn't sound familiar to you, ReactiveCocoa is an FRP* inspired framework, counting remarkable usage in…blog.alltheflow.com Let’s go back in time to when Apple introduced Swift, the successor to good old Objective-C, it was a very…

Prezi — the Land of the Polyglots

“I speak Spanish to God, French to women, English to men, and Japanese to my horse.” —Buckaroo Banzai Ask any engineer “which programming language is the best?”, and you’ll get crushed by a deluge of answers ranging from stuff they started with in uni to something they…

Plans Are Useless, Automation Is Essential

Racing against race conditions

Some hours ago, we discovered a bug related to our Facebook/LinkedIn signup integration. It meant that in a very particular and unlikely set of circumstances, some people may have found themselves in someone else’s Prezi account. In the moments since discovering this problem we: mumbled expletives fixed the problem stayed…

Prometheus at Prezi: replacing 10 years of anti-patterns

What happens when you combine 10 years of architectural organic build-up and a lack of common best practices around monitoring? Bad on-call shifts, more outages, longer outages and a lack of technical flexibility. In our effort towards uniformity and reliability, we redesigned our entire monitoring stack and created a new…