VTK/Git

VTK version tracking and development is hosted by Git.

Official Repository

One may browse the repository online using the Gitweb interface at http://vtk.org/VTK.git.

Cloning

One may clone the repository using git clone through the native git protocol:

$ git clone git://vtk.org/VTK.git VTK

or through the (less efficient) http protocol:

$ git clone http://vtk.org/VTK.git VTK

All further commands work inside the local copy of the repository created by the clone:

$ cd VTK

For VTKData the URLs are

git://vtk.org/VTKData.git
http://vtk.org/VTKData.git

Branches

At the time of this writing the repository has the following branches:

• master: Development (default)
• hooks: Local commit hooks (place in .git/hooks)

Release branches converted from CVS have been artificially merged into master. Actual releases have tags named by the release version number.

Development

We provide here a brief introduction to VTK development with Git. See the Resources below for further information such as Git tutorials.

Introduction

We require all commits in VTK to record valid author/committer name and email information. Use git config to introduce yourself to Git:

$ git config --global user.name "Your Name"
$ git config --global user.email "you@yourdomain.com"

While you're at it, optionally enable color output from Git commands:

$ git config --global color.ui auto

The --global option stores the configuration settings in ~/.gitconfig in your home directory so that they apply to all repositories.

Hooks

This step is optional but recommended.

The git commit command creates local commits. A separate git push step is needed to publish commits to vtk.org/VTK.git. The vtk.org server enforces some rules on the commits it accepts and will reject non-conforming commits (TODO: document these on this page and link from here). In order to push rejected commits, one must edit history locally to repair them before publishing.

Since it is possible to create many commits locally and push them all at once, we provide local Git hooks to help developers keep their individual commits clean. Git provides no way to enable such hooks by default, giving developers maximum control over their local repositories. We recommend enabling our hooks manually in all clones.

Git looks for hooks in the .git/hooks directory within the work tree of a local repository. Create a new local repository in this directory to manage the hooks:

$ cd .git/hooks
$ git init

The vtk.org/VTK.git repository provides a hooks branch. It will have already been fetched into your local clone. Pull it from there:

$ git pull .. remotes/origin/hooks

The hooks will now run in the outer repository to enforce some rules on commits. See Git help on githooks for details.

Publishing

Authorized developers may publish work directly to vtk.org/VTK.git using Git's SSH protocol.

Note that we may not grant all contributors push access to the vtk.org repository. The distributed nature of Git allows contributors to retain authorship credit even if they do not publish changes directly.

Authentication

All publishers share the git@vtk.org account but each uses a unique ssh key for authentication. If you do not have a public/private ssh key pair, generate one:

$ ssh-keygen -C 'you@yourdomain.com'
Generating public/private rsa key pair.
Enter file in which to save the key ($HOME/.ssh/id_rsa):
Enter passphrase (empty for no passphrase): (use-a-passphrase!!)
Enter same passphrase again: (use-same-passphrase!!)
Your identification has been saved in $HOME/.ssh/id_rsa.
Your public key has been saved in $HOME/.ssh/id_rsa.pub.

To request access, fill out the Kitware Password form. Include your ssh public key, id_rsa.pub, and a reference to someone our administrators may contact to verify your privileges.

Generating an ssh key on Windows

If you are familiar with generating an ssh key on Linux or Mac, you can follow the same procedure on Windows in a "Git Bash" prompt. There is an ssh-keygen program installed with msysGit to help you set up an ssh identity on a Windows machine. By default it puts the ".ssh" directory in the HOME directory, which is typically "/c/Users/Username" on Vista and Windows 7; on XP, it's "/c/Documents and Settings/Username".

Alternatively, you can also set up a "normal" Windows command prompt shell such that it will work with msysGit, without ever invoking the Git Bash prompt if you like. If you install msysGit and accept all its default options, "git" will not be in the PATH. However, if you add "C:\Program Files (x86)\Git\cmd" to your PATH, then only the two commands git and gitk are available to use via *.cmd script wrappers installed by msysGit. Or, if you add "C:\Program Files (x86)\Git\bin" to your PATH, then all of the command line tools that git installs are available.

The full PuTTY suite of tools includes an application called PuTTYgen. If you already have a private key created with PuTTYgen, you may export it to an OpenSSH identity file. Open the key using PuTTYgen and choose "Conversions > Export OpenSSH key" from the menu bar. That will allow you to save an "id_rsa" file for use in the ".ssh" directory. You can also copy and paste the public key portion of the key from the PuTTYgen text field to save into an "id_rsa.pub" file if you like. Or email it to whoever needs the public side of your key pair.

If you routinely set up your own command prompt environment on Windows, using msysGit from that envrionment is a cinch: just add the full path to either Git\cmd or Git\bin to your PATH. (Or, write your own git.cmd wrapper that is in your PATH that simply calls the git.cmd installed with msysGit.) And make sure you have a HOME environment variable that points to the place where the .ssh directory is.

Pushing

Pushes to the VTK.git repository have been disabled during the final transition to Git.

Git automatically configures a new clone to refer to its origin through a remote called origin. Initially one may fetch or pull changes from origin, but may not push changes to it.

In order to publish new commits in the vtk.org repository, developers must configure a push URL for the origin. Use git config to specify an ssh-protocol URL:

$ git config remote.origin.pushurl git@vtk.org:VTK.git

(Note that 'pushurl' requires Git >= 1.6.4. Use just 'url' for Git < 1.6.4.)

Once your push URL is configured and your key is installed for git@vtk.org then you can try pushing changes.

Resources

Additional information about Git may be obtained at these sites:

• Git Homepage
• Git Documentation Wiki
• Git Community Book
• Everyday Git
• Git Cheat-Sheet
• Pro Git
• A Visual Git Reference