Mirroring Repos with GitHub

by on under how-to
4 minute read

As I was migrating from GitHub to GitLab on Monday*, I began to imagine the awkward conversation I would have if I was ever in a Microsoft interview. Heck, the GitHub vs GitLab discussion feels like it’s on its way to becoming a religious debate like tabs vs spaces — the last thing I’d want to get into while networking.

After sleeping on it, I decided the best solution would be to have GitHub mirror all my GitLab repositories. That way, anyone I’m showing my code to can use their prefered platform and I don’t have to risk getting into an argument. Only problem is, unlike GitLab, GitHub does not have a “Mirror Repository” option when creating a new project… Time for a work-around!

Solution

As it turns out, git allows you to push to multiple URLs simply by adding one line to your .git/config! Here is the relevant excerpt from this website’s repo.

[remote "origin"]
    url = git@gitlab.com:kirklange/kirklange.gitlab.io.git
    fetch = +refs/heads/*:refs/remotes/origin/*
    pushurl = git@gitlab.com:kirklange/kirklange.gitlab.io.git
    pushurl = git@github.com:kirklange/kirklange.github.io.git

Whenever you execute git push, it pushes to each pushurl. Even if you are pushing to two remote repos that aren’t in sync, git will account for this and push what is necessary to each repo. In other words, if you’ve only been pushing to GitLab since you switched, your GitHub repo will catch up like nothing ever happened. (Even your green squares should sync up!)

If you also want the ability to pull from your secondary repo, you’ll want your .git/config to be of this format.

[remote "origin"]
    url = git@gitlab.com:kirklange/kirklange.gitlab.io.git
    url = git@github.com:kirklange/kirklange.github.io.git
    fetch = +refs/heads/*:refs/remotes/origin/*

However, it’s probably best not to pull from your secondary repo as to mitigate the chances of having to tediously merge the two. Afterall, the goal here is only to have the GitHub repo act as a mirror.

Disclaimer

Fine, this is technically not “mirroring”, but until Microsoft catches up to GitLab in terms of its extra features, this is the best we can do. Please let me know if you have a better solution. If anything comes up, I’ll make sure to update this post and give credit. Thanks!

Source


*Addendum

The real reason I switched to GitLab (for now).

I don’t give a damn whether GitLab is hosted on Azure or Google Cloud. I am well aware that Microsoft isn’t going to claim my code and that they don’t care about my rushed AI class project that is in freakin’ C89 for no good reason. What I care about most is how easily I can host, share, document, and test my projects.

In the past couple of years, I’ve been moving away from Microsoft software in general, going from Visual C++, Visual Studio, and Windows, to GNU, Vim, and (at least on my laptop) Ubuntu. The aquisition prompted me to revisit GitLab because I wasn’t sure whether Microsoft would move the platform in a direction that I would be interested in. Earlier this year, a classmate introduced me to GitLab but I brushed it off because I didn’t understand all that it had to offer.

After importing a couple projects to GitLab and tinkering around a bit, I was pleasantly surprised. A couple pet peeves I had with GitHub like pull request permissions and of course the ability to host private repositories were solved with GitLab. Additionally, having CI built right in to GitLab is pretty nice since I use it extensively to run unit and cross-platform compatability tests. That is not to say that GitLab doesn’t have its own issues. I definitely may find more in the future as it’s only my 3rd day using GitLab, but I figure where’s the harm in trying it out for a couple weeks?

Thanks to the fact that I’m pushing all my repo changes to both GitHub and GitLab, I can easily switch my main platform at will. If GitLab has another database outage, no big deal, most of what I care about is probably still on my local machine or on GitHub. If Microsoft ruins GitHub for me, also no big deal. The more options the better, for both me and the people I am sharing my code with.

gitlab, github, git, mirror, repo, repository, microsoft
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