pure go lib for git

[vtolstov]

What do you think about https://github.com/src-d/go-git , i use it for some git operations like pull, clone and other and it works fine. As i know gogs work with git via adaptor package, so i can try to create replacement for git operations in pure go. Does this acceptable or not ?

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[tboerger]

If it can entirely replace the git cli and doesn't depend on cgo I'm fine with that

[ekozan]

take care about the performance ;)

[JetpackDuba]

Why go-git instead of https://github.com/libgit2/git2go ? Imo libgit2 is really good

[tboerger]

Because it requires cgo and libgit.

[lunny]

The first version of Gogs is based https://github.com/gogits/git. We have tried to use pure Go. But it developments slowly and run slower than git command. If the https://github.com/src-d/go-git is full-featured and almost the same performance with git command, I prefer that.

[strk]

It would be worth using an interface for git operations and support either pure-go implementation or libgit2, with a build tag. The sqlite backend is also cgit so I don't see why not allowing it in codebase...

[lunny]

Great idea, we indeed need an interface on go-gitea/gitea and let go-gitea/git become as the default implementation.

[bkcsoft]

@lunny I'd rather put the interface in go-gitea/git and have the build-tag there TBH, otherwise we'd end up in a state where we need an interface in gitea, a wrapper for go-git and a wrapper for gitea/git

[lunny]

@bkcsoft How about mixed the two methods since https://github.com/src-d/go-git maybe not full-feature?

[bkcsoft]

Hence the proposal for having both in the same repo (go-gitea/git), that way we can have commit_exec.go and commit_pure.go where we can, and only repo_merge_exec.go where src-d/go-git isn't usable 🙂

[strk]

+1 for doing this in `go-gitea/git`

[typeless]

Continued from #1511

@strk

If I read correctly the code in its current version does not support merges ?

Yes.

See https://github.com/src-d/go-git
Also, are you suggesting to use this as one of the implementations of the go-gitea/git interface as proposed somewhere else or as the primary API for git work ?

My proposal was to use it as the primary API replacing go-gitea/git/
The approach using go-gitea/git as the interface is okay to me. But such abstraction can be eliminated in the long term.

Did you test performance compared to libgit ?

No. I assume it would have good, if not better, performance than other alternatives if the cgo overhead doesn't matter that much. But cgo does affect the developer experience to some extent.

[lunny]

A performance compare on a git sub command is welcome. For example, get releases page is too slow, if we use this library will retrieve better performance, it's great!

[bkcsoft]

It should be fairly simple to test performance gains like this:

• Add benchmark to current forking command
• Add pure-go command with benchmarks
• Run both benchmarks and compare

[filipnavara]

Just a heads-up: I actually made some effort in this direction, it is discussed in issue #491 along with links to my code and some performance numbers.

[pjebs]

If I was to work on integrating gitea with https://github.com/src-d/go-git, where do I start?

[lunny]

@pjebs I think you could send PRs to https://github.com/go-gitea/git to instead git commands to pure go library. I think it's easier to do it step by step.

[typeless]

@pjebs Incrementally implementing the exported APIs of https://github.com/go-gitea/git seems to be a good idea.

[filipnavara]

@pjebs Follow the suggestion by @typeless and @lunny. I already have a branch where I started doing that, so if you split the git module changes and gitea changes and help upstream it I'd be more than grateful. https://github.com/filipnavara/gitea/tree/perf-read

[pjebs]

Give me some time to understand the code base since I only found the repo a few days ago.
Then I'll look at starting the process.

[lunny]

@pjebs I think there are some part has used https://github.com/src-d/go-git and @filipnavara contributed a lot. You can go to modules/git to find them.

[6543]

since we use both (go-git and a git warper) and it doesn't look like go-git can take up for all git tasks I'll close this for now.
It can be reconsidered in the future if things change ...