Announcing Hound: A Lightning Fast Code Search Tool

Today we are open sourcing a new tool to help you search large, complex codebases at lightning speed. We are calling this tool Hound. We’ve been using it internally for a few months, and it has become an indispensable tool that many engineers use every day.

The Problem Hound Solves

Before Hound, most engineers used ack or grep to search code, but with our growing codebase this started taking longer and longer. Even worse, searching across multiple repositories was so slow and cumbersome that it was becoming frustrating and error prone. Since it is easy to overlook dependencies between repositories, and hard to even know which you might need to search, this was a big problem. Searching multiple repositories was especially painful if you wanted to search a repo that you didn’t have cloned on your machine. Due to this frustration, Kelly starting working on a side project to try out some of the ideas and code from this article by Russ Cox. The code was robust, but we wanted to tweak some of the criteria for excluding files, and create a web UI that could talk to the search engine.

The end goal was to provide a simple web front-end with linkable search results that could perform regular expression searches on all of our repositories quickly and accurately. Hound accomplishes this with a static React front-end that talks to a Go backend. The backend keeps an up-to-date index for each repository and answers searches through a minimal API.

Why Create a New Tool?

Some people might point out that tools like this already exist – OpenGrok comes to mind immediately. Our main beef with OpenGrok is that it is difficult to deploy, and it has a number of hard requirements that are not trivial to install and configure. To run Hound you just need Go 1.3+. That’s it. A browser helps to see the web UI, but with a command line version on the way and a Sublime Text plugin already live, the browser is optional. We wanted to lower the barrier to entry for this tool so much that anyone, anywhere, could starting using Hound to search their code in seconds or minutes, not hours.

Get It

Hound is easy enough to use that we recommend you just clone it and see for yourself. We have committed to using the open source version of Hound internally, so we hope to address issues and pull requests quickly. That’s enough jibber jabber – check out the quick start guide and get searching!

Hound trained at Etsy by Jonathan Klein and Kelly Norton