Replaced

Backlog's Git Server

From Perl To Go

#gocon Spring 2018 by Yuichi Watanabe @nulab

# Introduction

vvatanabe

vvatanabe

# What is a Git Server ?

• Replaced a server for accessing Git remote repository via HTTP. That is where the Gopher is in the diagram below.

• In order to access a Git remote repository by HTTP, something is needed in front the remote repository, to handle the HTTP requests occurring in clone, push, fetch etc.

The Git Server basically implements behavior for each endpoint according to the Smart Protocol specification defined by Git.

# What is a Git Server ?

# Motivation

Backlog has a subsystem that stood out a bit, a Git HTTP Server written in Perl. This Git HTTP Server itself does not undergo a lot of development. It's a relatively small system whose responsibility is not too large. I felt that the enthusiasm of maintaining this system within my team, including myself, was gradually decreasing. Also, we currently don't have a Perl Hacker our team.

# Motivation

At the same time, Backlog users are steadily increasing.

I thought I could improve our motivation, the maintainability, and performance by replacing the Git Server using Golang.

Don't guess, measure !

 

I decided to rewrite and measure it, as the proverb goes.

# Motivation

# Comparison Structure

## It could handle many requests.

# Improvments

100ms

400ms

Golang

Perl

## It could handle many requests.

Perl

Golang

# Improvments

60%

100%

### CPU usage

## It could handle many requests.

Perl

Golang

# Improvments

### Load Average

The speed of git clone and push improved by 2x times.

The larger the Git repository, the larger the speed difference.

## Improved the user experience of clone

# Improvments

## And More...

• Reduced memory used for pre-forking the process.

      > Perl:      2.082456 MB

      > Golang: 24.664 KB

• Deployment is simple as it is compiled into a single binary.

• We were able to focus on writing code without worrying about code formatting thanks to `go fmt`.​

• Since golang is statically typed, We ware able to use code completion which improved my efficiency.

# Improvments

As a result, The performance improved. However, It's difficult to compare Perl and Golang,  as they are so different. Golang is a compiled language and has lightweight threading. 

I got a lot of insight on the design of Web applications written in Perl and eventually learned a lot about the Perl programming language.

I saw Geek 's wonderful hack footprints, I've come to like Perl than before.

Thank you for Perl, for your hard work. Hello Golang.

# Finally

Thanks !