https://github.com/crhntr/explore-go-git-wasm

Is it currently possible to use go-git in the browser? Not really... but I made it work.
https://github.com/crhntr/explore-go-git-wasm

git go wasm

Last synced: about 1 month ago
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Is it currently possible to use go-git in the browser? Not really... but I made it work.

• Host: GitHub
• URL: https://github.com/crhntr/explore-go-git-wasm
• Owner: crhntr
• Created: 2020-01-09T01:22:48.000Z (almost 5 years ago)
• Default Branch: master
• Last Pushed: 2023-02-25T07:04:18.000Z (almost 2 years ago)
• Last Synced: 2024-06-21T18:01:13.137Z (6 months ago)
• Topics: git, go, wasm
• Language: Go
• Homepage:
• Size: 747 KB
• Stars: 1
• Watchers: 3
• Forks: 0
• Open Issues: 3
• Metadata Files:
  • Readme: README.md

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README

        
# Using the go-git package in the browser

## Abstract

Go now supports [Web Assembly]((https://github.com/golang/go/wiki/WebAssembly)), which runs in most browsers.

Go-Git supports fully [in memory](https://github.com/go-git/go-git#in-memory-example) plumbing and "ceramic" operations.

Git can be hard to understand and DOM (document object model) visualizations of the state could be really cool.

I tried to compile a Go program that imports and uses the go-git package.

By refactoring when and how the osfs package gets imported in go-git we can use git in the browser.

I have a tagged release here with the required go-git changes: https://github.com/crhntr/go-git/releases/tag/wip-js-wasm

To get my proof-of-concept release run `go get github.com/crhntr/go-git@wip-js-wasm`

and add `replace github.com/go-git/go-git/v5 v5.2.0 =>  github.com/crhntr/go-git/v5 ` to your module file. 

## Methodology

- Get imported modules

  `go mod vendor`

- Find usages of packages that do non-wasm-supproted os syscalls

  go-git abstracts the filesystem and OS interactions using the go-billy Filesystem. 

  The go-billy/inmem Filesystem works in browser wasm environments [see github.com/crhntr/explore-go-billy-wasm](https://github.com/crhntr/explore-go-billy-wasm).

  

  The go-billy implementation that is not supported in the browser is [go-billy/osfs](https://github.com/go-git/go-billy/tree/master/osfs), which wraps the standard library filesystem package.

  

  To find uses of osfs, I ran the following

  

  ```sh

  cd vendor

  ag gopkg.in/src-d/go-billy.v4/osfs

  ```

  

  ```

  github.com/go-git/go-git/v5/remote.go

  9:      "github.com/go-git/go-billy/v5/osfs"

  

  github.com/go-git/go-git/v5/storage/filesystem/dotgit/dotgit.go

  17:     "github.com/go-git/go-billy/v5/osfs"

  

  github.com/go-git/go-git/v5/plumbing/transport/server/loader.go

  10:     "github.com/go-git/go-billy/v5/osfs"

  

  github.com/go-git/go-git/v5/repository.go

  33:     "github.com/go-git/go-billy/v5/osfs"

  ```

  

  The osfs package is used in the following files:

  

  In repository.go

  - func PlainInit

  - func dotGitToOSFilesystems

  - func dotGitFileToOSFilesystem

  

  In remote.go

  - func PushContext

  

  In storage/filesystem/dotgit.go

  - func Alternates

  

  I then factored out the usages of osfs (see diff here: https://github.com/crhntr/go-git/commit/09378a6e8d4bb3078f6f4de990c22c40077bafd5).

  I did not check for network usage that would not be supported in Go wasm environments.

## Results

There are a few imports that do not allow go-git to be imported in a Go program compiled for the browser. Some refactors could make this work.

## Developer Notes

`./start.sh` is a script that starts a web server that loads the wasm into the browser.