How do you organise multiple git repositories?

Question

With SVN, I had a single big repository I kept on a server, and checked-out on a few machines. This was a pretty good backup system, and allowed me easily work on any of the machines. I could checkout a specific project, commit and it updated the 'master' project, or I could checkout the entire thing.

Now, I have a bunch of git repositories, for various projects, several of which are on github. I also have the SVN repository I mentioned, imported via the git-svn command..

Basically, I like having all my code (not just projects, but random snippets and scripts, some things like my CV, articles I've written, websites I've made and so on) in one big repository I can easily clone onto remote machines, or memory-sticks/harddrives as backup.

The problem is, since it's a private repository, and git doesn't allow checking out of a specific folder (that I could push to github as a separate project, but have the changes appear in both the master-repo, and the sub-repos)

I could use the git submodule system, but it doesn't act how I want it too (submodules are pointers to other repositories, and don't really contain the actual code, so it's useless for backup)

Currently I have a folder of git-repos (for example, ~/code_projects/proj1/.git/ ~/code_projects/proj2/.git/), and after doing changes to proj1 I do git push github, then I copy the files into ~/Documents/code/python/projects/proj1/ and do a single commit (instead of the numerous ones in the individual repos). Then do git push backupdrive1, git push mymemorystick etc

So, the question: How do your personal code and projects with git repositories, and keep them synced and backed-up?

Answer 1

I haven't tried nesting git repositories yet because I haven't run into a situation where I need to. As I've read on the #git channel git seems to get confused by nesting the repositories, i.e. you're trying to git-init inside a git repository. The only way to manage a nested git structure is to either use git-submodule or Android's repo utility.

As for that backup responsibility you're describing I say delegate it... For me I usually put the "origin" repository for each project at a network drive at work that is backed up regularly by the IT-techs by their backup strategy of choice. It is simple and I don't have to worry about it. ;)

Answer 2

I would strongly advise against putting unrelated data in a given Git repository. The overhead of creating new repositories is quite low, and that is a feature that makes it possible to keep different lineages completely separate.

Fighting that idea means ending up with unnecessarily tangled history, which renders administration more difficult and--more importantly--"archeology" tools less useful because of the resulting dilution. Also, as you mentioned, Git assumes that the "unit of cloning" is the repository, and practically has to do so because of its distributed nature.

One solution is to keep every project/package/etc. as its own bare repository (i.e., without working tree) under a blessed hierarchy, like:

/repos/a.git
/repos/b.git
/repos/c.git

Once a few conventions have been established, it becomes trivial to apply administrative operations (backup, packing, web publishing) to the complete hierarchy, which serves a role not entirely dissimilar to "monolithic" SVN repositories. Working with these repositories also becomes somewhat similar to SVN workflows, with the addition that one can use local commits and branches:

svn checkout   --> git clone
svn update     --> git pull
svn commit     --> git push

You can have multiple remotes in each working clone, for the ease of synchronizing between the multiple parties:

$ cd ~/dev
$ git clone /repos/foo.git       # or the one from github, ...
$ cd foo
$ git remote add github ...
$ git remote add memorystick ...

You can then fetch/pull from each of the "sources", work and commit locally, and then push ("backup") to each of these remotes when you are ready with something like (note how that pushes the same commits and history to each of the remotes!):

$ for remote in origin github memorystick; do git push $remote; done

The easiest way to turn an existing working repository ~/dev/foo into such a bare repository is probably:

$ cd ~/dev
$ git clone --bare foo /repos/foo.git
$ mv foo foo.old
$ git clone /repos/foo.git

which is mostly equivalent to a svn import--but does not throw the existing, "local" history away.

Note: submodules are a mechanism to include shared related lineages, so I indeed wouldn't consider them an appropriate tool for the problem you are trying to solve.

Answer 3

I would strongly advise against putting unrelated data in a given Git repository. The overhead of creating new repositories is quite low, and that is a feature that makes it possible to keep different lineages completely separate.

Fighting that idea means ending up with unnecessarily tangled history, which renders administration more difficult and--more importantly--"archeology" tools less useful because of the resulting dilution

The problem with making a separate repository for every single project is a lot of my code isn't a project, it's often a bunch of random scripts, snippets, completely-unrelated-to-code writing, things which never change once written. I would find it very hard to organise the files into anything resembling projects, with the exception of about 4-5 folders (of about 300 directories, and 1000 files) - which I already have a separate repos.

With my master repository, I basically just use it as a linear history/backup/undo-tool. The problem I have is syncing the files in those 4-5 projects with my master-repo.

I'm not sure if there is a simple solution to what I want to do.. I may just write a simple script to copy the changes from the few projects I have separated, into the master repo (basically copy blah.py blah2.py ~/Documents/code/python/project/blahproj/ && cd !$ && git commit -v)

The specifics of my problem aside, how are you organising your random code and such in git? If you split everything into lots of repositories, how segmented do you have it?

Answer 4

I want to add to the answer which recommends doing:

$ for remote in origin github memorystick; do git push $remote; done

that you can setup a special remote to push to all the individual real remotes with 1 command; I've seen it in http://marc.info/?l=git&m=116231242118202&w=2:

So for "git push" (where it makes sense to push the same branches multiple times), you can actually do what I do:

• .git/config contains:

  [remote "all"]
  url = master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6
  url = login.osdl.org:linux-2.6.git
  

• and now git push all master will push the "master" branch to both
  of those remote repositories.

You can also save yourself typing the URLs twice by using the contruction:

[url "<actual url base>"]
    insteadOf = <other url base>

Answer 5

Off topic, but where can I find a step-by-step guide that explains exactly what git is, when to use it, and how to use it? For instance, is it helpful with a big PHP project?

Answer 6

I also am curious about suggested ways to handle this and will describe the current setup that I use (with SVN). I have basically created a repository that contains a mini-filesystem hierarchy including its own bin and lib dirs. There is script in the root of this tree that will setup your environment to add these bin, lib, etc... other dirs to the proper environment variables. So the root directory essentially looks like:

./bin/            # prepended to $PATH
./lib/            # prepended to $LD_LIBRARY_PATH
./lib/python/     # prepended to $PYTHONPATH
./setup_env.bash  # sets up the environment

Now inside /bin and /lib there are the multiple projects and and their corresponding libraries. I know this isn't a standard project, but it is very easy for someone else in my group to checkout the repo, run the 'setup_env.bash' script and have the most up to date versions of all of the projects locally in their checkout. They don't have to worry about installing/updating /usr/bin or /usr/lib and it keeps it simple to have multiple checkouts and a very localized environment per checkout. Someone can also just rm the entire repository and not worry about uninstalling any programs.

This is working fine for us, and I'm not sure if we'll change it. The problem with this is that there are many projects in this one big repository. Is there a git/Hg/bzr standard way of creating an environment like this and breaking out the projects into their own repositories?

Answer 7

There is another method for having nested git repos, but it doesn't solve the problem you're after. Still, for others who are looking for the solution I was:

In the top level git repo just hide the folder in .gitignore containing the nested git repo. This makes it easy to have two separate (but nested!) git repos.