In Harmony

Using the Go Interface mechanism, Mike demonstrates its practical application with a refresh program for local copies of Git repositories.

- Mike Schilli

Vacation time is travel time! I like to take my laptop with me on long-haul flights. After all, the best ideas for new articles always come to me at the worst possible times. But, without an Internet connection, neither Google nor ChatGPT work, and GitHub is also out of reach for code ideas. Even the stuff I wrote previously is stashed away in Git repositories, and – worse still – the copies on my laptop are not always up to date. That’s really annoying, because it means duplicating the work, which I want to avoid, or at least pesky integration and potential conflict-resolution tasks later, when I look to reconcile the texts I checked in while I was up in the air with an out of sync repository.

Wouldn’t it be great to fire up a program on my laptop before the plane takes off to update the local copies of all my checked-out Git repositories? It would need to sync the existing clones on the laptop with the latest cloud version until Git reported “up-to-date,” as well as clone repositories I previously only checked out on my home computer on my laptop to deliver all the resources I can access at home.

Meta Format

Now the little helper can’t read my mind (yet) and simply load everything that I think is important. That’s why I went for a meta file, as shown in Figure 1, to specify the repositories and define the directory names in each new development environment. It contains an array in YAML format whose elements under the keywords dir and url contain the clone directory and the URL of a repository I want to clone. Because this is GitHub repository metadata, the format, for historical reasons, should be called GitHub Meta Format (GMF), because I wrote it in Perl 15 years ago and introduced it in my column [1]. Fast forward to today, and there’s an opportunity to rewrite it in Go and at the same time demonstrate Go’s cool interface mechanism for plu gin-based architecture!