A few days ago I was configuring Subversion on one of my linux servers and I started looking for a way to dynamically expose the repositories complete with a separate users database. I was hoping to make it totally dynamic so that I could just add a new repository, configure the permissions (see my earlier post on per-directory access controls) and create the accounts. I tried something like this:

<VirtualHost virtual-host-1:80>
 ServerName svn.domain.tld
 
 SetEnvIf Request_URI "/([^/]+)(?:/?|/.*)?" REPOSITORY_NAME=$1
 
 <Location />
  DAV svn
  SVNPath /path/to/svnrepositories/${REPOSITORY_NAME}
  AuthzSVNAccessFile /path/to/svnrepositories/${REPOSITORY_NAME}/conf/httpd.access
  AuthUserFile /path/to/svnrepositories/${REPOSITORY_NAME}/conf/httpd.passwd
  Require valid-user
  AuthType Basic
  AuthName "Subversion Repository"
 </Location>
</VirtualHost>

The key is this line: SetEnvIf Request_URI "/([^/]+)(?:/?|/.*)?" REPOSITORY_NAME=$1¹. If you browse to http://svn.domain.tld/someRepository it conditionally sets an Apache environment variable to someRepository which you can use to reference a specific repository, password file and access list. Perfect, right?

Unfortunately it's not that easy – you can't use dynamically set environment variable in any directive arguments. Crap! There are some other solutions out there like mod_macro, but I've had some issues with that in the past. mod_perl and a <Perl> tag might work, but I've never used that before and I want to keep my configuration simple (and minimize the time spent on this).

I decided to take the easy way out and sacrifice some functionality. The SVNParentPath directive allows you to define a path under which any directories will be assumed to be SVN repositories. Now I can add new repositories on the fly without restarting Apache, but I still don't have multiple user files.

In the end having distinct user files isn't that big of a deal, especially if you aren't worried about username conflicts and because you can control permissions on a per-repository basis in your user file. Here's a sample access file:

[groups]
group1 = bill, joe
 
[/]
# By default no one except corey has permissions at the root level
* =
corey = rw
 
[Some_Project:/]
# grant all members of group1 full permissions on Some_Project
# corey will inherit permissions from /
@group1 = rw

My final Apache configuration looked like this:

<VirtualHost virtual-host-1:80>
 ServerAdmin webmaster@domain.tld
 DocumentRoot /home/domain/public_html
 ServerName svn.domain.tld
 
 <Location />
  DAV svn
  SVNParentPath /home/domain/svn
  AuthzSVNAccessFile /home/domain/svnauth/httpd.access
  AuthUserFile /home/domain/svnauth/httpd.passwd
  Require valid-user
  AuthType Basic
  AuthName "Subversion Repository"
 </Location>
</VirtualHost>

As always, the book Version Control with Subversion (buy it from Amazon) was a big help.

1. If you want to use parenthesized expressions with SetEnvIf you'll need Apache 2.0.51 or newer. [back]

Posted on Monday, August 20th, 2007 at 7:50 am | Filed under Development, Software, Technology
You can follow any responses to this entry through the Comments feed.
Post a Comment | Trackback URL | Permalink URL