Sunday, March 23, 2014

Managing dot-files with vcsh and myrepos

Say I want to get my dot-files out on a new computer. Here's what I do:

# install vcsh & myrepos via apt/brew/etc
vcsh clone https://github.com/tfnico/config-mr.git mr
mr update

Done! All dot-files are ready to use and in place. No deploy command, no linking up symlinks to the files. No checking/out in my entire home directory as a Git repository. Yet, all my dot-files are neatly kept in fine-grained repositories, and any changes I make are immediately ready to be committed:

config-atom.git
    -> ~/.atom/*

config-mr.git
    -> ~/.mrconfig
    -> ~/.config/mr/*

config-tmuxinator.git  
    -> ~/.tmuxinator/*

config-vim.git
    -> ~/.vimrc
    -> ~/.vim/*

config-bin.git   
    -> ~/bin/*

config-git.git          
    -> ~/.gitconfig

config-tmux.git  
    -> ~/.tmux.conf    

config-zsh.git
    -> ~/.zshrc

How can this be? The key here is to use vcsh to keep track of your dot-files, and its partner myrepos/mr for operating on many repositories at the same time.


I discovered vcsh when I had its creator, Richard Hartmann guesting on GitMinutes, and I'm still surprised how little known this great tool is. Partly responsible for this I guess is that it's a bit hard to understand how vcsh works, and the README only does a half-good job at explaining it.

So let me try with my own words:

vcsh is a sort of a Git wrapper that let's you track files in Git repositories, while the actual files (work-tree) are in your home directory. 

For example, my .gitconfig is tracked in this repository: 

~./config/mr/repo.d/config-git.git (see it on GitHub)

But vcsh sets the working directory to be ~, so when I check out the contents of the repository, it lands directly in my home directory.

vcsh works pretty much like Git, except for most commands you tell it which repository to work on:

vcsh init git # creates a bare repository by with the name 'git' under ~./config/mr/repo.d/
vcsh git add .gitconfig # adds the file to the 'git' repository
vcsh git commit -m "My initial .gitconfig"
vcsh git diff # shows any changes you have made to your .gitconfig since

If you know about Git's ability to keep the GIT_DIR separate from the work-tree, this should be pretty easy to grasp.

Enter myrepos

If you're happy to keep all your dot-files in one repository, you'd be well off using vcsh by itself. But if you prefer having several repositories (perhaps you don't want all dot-files on a particular computer), or if you have any other Git repositories you always need checked out on your computer, myrepos is the tool for syncing a bunch of repositories in one go.

Imagine myrepos like this: It's a file with a list of repositories to should be managed on your computer:

[$HOME/projects/foo]
checkout = git clone git@github.com:tfnico/foo.git

[$HOME/projects/bar]
checkout = git clone git@github.com:tfnico/bar.git

Lucky for us, it also does the right thing with vcsh repositories:

[$HOME/.config/vcsh/repo.d/various.git]
checkout = vcsh clone git@github.com:tfnico/config-various.git various

That's pretty straight forward. Now you'll soon realize that myrepos and vcsh overlap in the sense that they both can do Git operations, and this can be a bit confusing. I'll try postulating a bit on which is for what:
  • myrepos is for checking out or operating a bunch of repositories at the same time. This includes your vcsh repositories.
  • vcsh is for managing files and directories in your home directory. The contents of a vcsh repository is all relative to home.
  • The myrepos configuration is kept in a vcsh repository. So in order to bootstrap, doing a vcsh clone of our mr repository is the first thing we do (as we did near the top of this blog post).
  • As myrepos also operates your vcsh repositories, it also manages its own configuration. As an effect, if you make any changes to your myrepos config on one computer, you'll have to run `mr update` twice in order to see the changes on another computer.
  • If you're making changes on one repository, like your vim-config, use vcsh to diff and commit the changes.
  • If you want to push or pull all the latest changes in all your repositories, use myrepos.
Some food for thought: Consider my vcsh repo for myrepos - I could have kept the .mrconfig file by itself in a vcsh repository, and then have mr check out the ~/.conf/mr/ stuff as a normal mr.git repo inside of ~/.conf/. This hypothetical aside, it makes more sense to keep files for one purpose in one repo.

I can understand after writing this that it's really hard to come up with a good README for vcsh. But I like to consider how much time I've spent on dealing with my dot-files, and how much more time I spent not managing them. In light of that, spending half a day on getting vcsh and mr set up right doesn't seem too bad. They are simply the best tools for the job (and other jobs), and the only draw-back is a little learning curve.