VisualSVN Subversion Server and Git

I’d like to start this blog with a few real-world examples on how to set up SubGit assuming infrastructure that is already in place. This post will take place in a strange world of Windows.

Initial configuration: VisualSVN Server on 64-bit Windows computer, provides read and write access to two Subversion repositories over HTTPS.

Primary Objective: Make Subversion repositories accessible for reading and modification with Git over HTTPS.

Secondary Objective: Reuse existing authentication settings, that are already configured for Subversion repositories.

In other words I’m about to set up instant bidirectional Svn to Git replication.

Configuration Details

This is a VisualSVN configuration I’ve created for this guide:

Initial VisualSVN
Configuration

As you may see project repository is a single-project one with a standard trunk/branches/tags layout, and main repository contains two subproject, each with a standard layout.

VisualSVN is installed in C:\Program Files (x86)\VisualSVN Server directory.\ Repositories are located in C:\Repositories directory.\ VisualSVN uses standard Subversion authentication settings.

Add Git to Svn

First, install msysGit, you may download installer from their download page. Make sure you select this option when installing msysGit (it is important for enabling HTTP access later!):

Important Git Installation
Option

Second, change an account VisualSVN service uses and modify C:\Repository directory (one where repositories are kept) permissions as described in a Visual SVN knowledge base entry. It is important to make VisualSVN service run on behalf of the account that has access to the Git you’ve just installed. Following the way of lesser resistance, I’ve used my personal account for that, but you may create a dedicated one.

After completing this step, I had VisualSVN service running on behalf of “HOST\alex” account and C:\Repository was writable for “HOST\alex”. Yes, my name is Alex.

Finally, download SubGit zip archive and unpack it into C:\SubGit directory. The run “subgit install” on Subversion repositories to enable replication:

> C:\SubGit\bin\subgit install C:\Repositories\main
> C:\SubGit\bin\subgit install C:\Repositories\project

Install
SubGit

Install SubGit

Note, that you must run “subgit install” on behalf of the same user that you’ve configured VisualSVN service with.

Configure HTTP Access for Git

Important: VisualSVN comes with more or less truncated version of Apache, but fortunately it misses only one module of those needed for Git (mod_cgi). Download it (mod_cgi.so from Apache 2.2.21 for win32) and put into C:\Program Files (x86)\VisualSVN Server\bin directory.

Alternatively, you may get this missing module by installing Apache and taking mod_cgi.so file from the modules folder.

Then, edit C:\Program Files (x86)\VisualSVN Server\conf\httpd-custom.conf file:

LoadModule cgi_module bin/mod_cgi.so
LoadModule authz_user_module bin/mod_authz_user.so

SetEnvIf Request_URI "^/git/.*$" GIT_PROJECT_ROOT=C:/Repositories
SetEnvIf Request_URI "^/git/.*$" GIT_HTTP_EXPORT_ALL

ScriptAlias /git/ "C:/Program Files (x86)/Git/libexec/git-core/git-http-backend.exe/"

<Location /git>
  Options +ExecCGI

  Require valid-user
  AuthName "VisualSVN Server"
  AuthType Basic
  AuthBasicProvider file
  AuthUserFile "C:/Repositories/htpasswd"
</Location>

Note, that this configuration example uses “Basic” authentication option, granting read and write access to repositories for all Git users that are listed in htpasswd file. Of course you may configure something more complicated here.

Now restart VisualSVN Server service. That’s all!

Git for Svn

Try the following commands now:

# set this environment variable in case you're using SSL and 
# self-signed SSL certificate in VisualSVN (this is default).
> SET GIT_SSL_NO_VERIFY=true

> git clone https://alex@localhost/git/project project
> git clone https://alex@localhost/git/main/git/library lib

Thanks to SubGit, changes pushed from the cloned Git repository will be immediately propagated to the corresponding Svn repository and vice versa – new Svn revisions will be received by a pull performed from a cloned Git repository.

You may find more on SubGit at http://subgit.com/

Written on January 21, 2012