Dropbox traffic infrastructure: Edge network

In this post we will describe the Edge network part of Dropbox traffic infrastructure. This is an extended transcript of our NginxConf 2018 presentation. Around the same time last year we described low-level aspects of our infra in the Optimizing web servers for high throughput and low latency post. This time we’ll cover higher-level things like our points of presence around the world, GSLB, RUM DNS, L4 loadbalancers, nginx setup and its dynamic configuration, and a bit of gRPC proxying.

Dropbox scale

Dropbox has more than half a billion registered users who trust us with exabytes of data and petabytes of corresponding metadata.

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Migrating from Underscore to Lodash

Modernizing the front-end stack

The core Dropbox web application is 10 years old and used by millions of users per day. Hundreds of front-end engineers across multiple cities actively work on it. Unsurprisingly, our codebase is very large and somewhat irregular. Recently written parts have thorough test coverage, other parts haven’t been updated in years.

Over the past two years we’ve worked to modernize our front-end stack. We’ve successfully moved from CoffeeScript to TypeScript, from jQuery to React, and from a custom Flux implementation to Redux. Having completed these migrations we identified our utility library, Underscore, as one more candidate for migration.

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Improving Document Preview Performance

Introduction

Ever open a file on dropbox.com, or click a shared link your coworker sent you? Chances are you didn’t need to download the file to see it—you saw it right in the browser. This is the work of the Previews team at Dropbox.

Previews are part of the core Dropbox experience. They allow architects to access their entire portfolios on dropbox.com while at the job site to show their work. Designers can send work-in-progress to clients without worrying about whether they have the correct software installed. Office managers can review, comment, and annotate new office design proposals,

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Optimizing web servers for high throughput and low latency


This is an expanded version of my talk at NginxConf 2017 on September 6, 2017. As an SRE on the Dropbox Traffic Team, I’m responsible for our Edge network: its reliability, performance, and efficiency. The Dropbox edge network is an nginx-based proxy tier designed to handle both latency-sensitive metadata transactions and high-throughput data transfers. In a system that is handling tens of gigabits per second while simultaneously processing tens of thousands latency-sensitive transactions, there are efficiency/performance optimizations throughout the proxy stack, from drivers and interrupts, through TCP/IP and kernel, to library, and application level tunings.

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Memory-Efficient Image Passing in the Document Scanner

In our previous blog posts on Dropbox’s document scanner (Part 1, Part 2 and Part 3), we focused on the algorithms that powered the scanner and on the optimizations that made them speedy. However, speed is not the only thing that matters in a mobile environment: what about memory? Bounding both peak memory usage and memory spikes is important, since the operating system may terminate the app outright when under memory pressure. In this blog post, we will discuss some tweaks we made to lower the memory usage of our iOS document scanner.

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Improving the Responsiveness of the Document Detector

In our previous blog posts (Part 1, Part 2), we presented an overview of various parts of Dropbox’s document scanner, which helps users digitize their physical documents by automatically detecting them from photos and enhancing them. In this post, we will delve into the problem of maintaining a real-time frame rate in the document scanner even in the presence of camera movement, and share some lessons learned.

Document scanning as augmented reality

Dropbox’s document scanner shows an overlay of the detected document over the incoming image stream from the camera.

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