Academic Computing Subversion service

Overview

The Academic Computing Subversion hosting service is a tool that provides SEAS users, groups, and labs secure, manageable, and centralized access to Subversion repositories. These repositories can be public or private, and control can be managed as needed by their owners.

Creating a repository group

A "repository group" is a collection of Subversion repositories managed by a particular person or group.

Anyone with an active SEAS account may request a Subversion repository group by sending email to achelp@seas.harvard.edu. In your email, please specify the name you would like for the repository group. This may be your username, or it may be the name of a project or research group.

Managing your repository group

Once your repository group has been created, we will send you an email with the command necessary to check out the administrative repository. For a repository group named "bigproject", the command would look like this:

svn co https://source.seas.harvard.edu/svn/bigproject/admin/

This would create a directory called admin in your current directory with the contents of the administrative repository.

The admin repository

The admin repository is a meta-repository that allows you to control your Subversion repository group. The admin repository contains the following files and directories:

• authz
  This is the primary configuration file for the repository group. It is a standard Subversion authorization file, described in the Path-Based Authorization section of the Subversion book. This is where you create new repositories and control access to your repositories.

• htpasswd
  This is a standard Apache "htpasswd" file that can be used to provide access to your Subversion repositories for someone without a SEAS account.

• svnbiosis.conf
  This configuration file controls certain aspects of your repository group. You will generally not need to edit this file.

• keydir
  It is possible to access your Subversion repository via ssh instead of using http. This directory is where you would store ssh keys if you were using this mechanism. If you are interested in using ssh for Subversion access, please contact us.

Adding new repositories

You add new repositories to your repository group by adding new stanzas to the authz file and committing the changes. For example, to add a repository called "niftycode" to your "bigproject" repository group, you would add the following to your authz file:

[niftycode:/]
lars = rw

This grants read/write (rw) access to all of the niftycode repository to user lars. When you commit this change to the server, the server will create the niftycode repository if it does not already exist.

Note that there is no way to delete repositories. This is safety measure to prevent accidental typos from causing loss of data. If you remove a repository from your authz file, you can always put it back at a later date to restore access to the data.

Controlling access to repositories

You control access to repositories by editing the authz file in your administrative repository.

Granting access to people with SEAS accounts

To grant a user "alice" read access to your documents repository, you might modify the corresponding entry in your authz file from this:

[documents:/]
lars = rw

To look like this:

[documents:/]
lars = rw
alice = r

This gives alice the ability to view all of the documents repository. If instead you wanted alice to have access to only the unclassified directory of the repository, you would instead modify your authz file to look like this:

[documents:/]
lars = rw

[documents:/unclassified/]
alice = r

Granting access to people without SEAS accounts

If you will be collaborating with someone from outside of SEAS, you may to create a local account for them in your repository group. The htpasswd file is where you control local users and groups. The file is a list of lines of the form:

username:password

Where password is a password hash. You will typically manage entries in this file using the htpasswd program, which is part of a standard Apache install. If you do not have access to this program on your local computer, you can connect to login.seas.harvard.edu and generate entries there:

• Connect to login.seas.harvard.edu using ssh.
• Run htpasswd with the -n option, like this:
  htpasswd -n -m user@somewhere.com
• Enter and confirm the password when prompted, and htpasswd will emit a line similar to the following:
  user@somewhere.com:$apr1$Phvgf...$w4R6hgDtojkIZnCNjvyzy0
• Paste this line into your htpasswd file and commit the changes.

When selecting usernames, we encourage you to always use a person's email address.

Once you have created the user account, granting access is the same as described in the previous section. For example, you might modify your authz file to look like this:

[documents:/]
lars = rw
user@somewhere.com = r

Receiving emailed commit logs

If you want to receive an email message when someone commits changes to a repository, you may set the seas:review property on the repository root directory to a list of email addresses. For example:

$ cd myproject
$ svn propedit seas:review .
...make your changes...
$ svn ci -m 'added reviewers'