Web-based code browsing

Browsing the history of a project online is an important part of version control, since it allows people to easily see what happens in a branch without having to have a local, up-to-date copy of that branch. There are a number of possible choices for browsing Bazaar branches on the web, but we will cover one of them in particular detail and briefly mention the other choices where they differ.


Loggerhead is a code browsing interface for Bazaar branches (now used in Launchpad). To see an example of Loggerhead in action, browse to http://bazaar.launchpad.net/~bzr-pqm/bzr/bzr.dev/files which is the loggerhead view of Bazaar’s trunk branch. Loggerhead runs as a web application on the server which is accessed over HTTP via a RESTful interface. It is possible to run this application on its own dedicated port as http://www.example.com:8080 or to proxy this location behind a separate web server, for example at http://www.example.com/loggerhead/. We will discuss both of these configurations below.


Loggerhead depends on a number of other Python packages for the various Web technologies that it builds on. Some of these must be installed to use loggerhead, although some of them are optional. From the loggerhead README file, these are

  1. SimpleTAL for templating. On Ubuntu, sudo apt-get install python-simpletal or download from http://www.owlfish.com/software/simpleTAL/download.html
  2. simplejson for producing JSON data. On Ubuntu, sudo apt-get install python-simplejson or use easy_install simplejson.
  3. Paste for the server. (You need version 1.2 or newer of Paste.) On Ubuntu, sudo apt-get install python-paste or use easy_install Paste
  4. Paste Deploy (optional, needed when proxying through Apache) On Ubuntu, sudo apt-get install python-pastedeploy or use easy_install PasteDeploy
  5. flup (optional, needed to use FastCGI, SCGI or AJP) On Ubuntu, sudo apt-get install python-flup or use easy_install flup

Although directions for installing these on Ubuntu are given, most other GNU/Linux distributions should package these dependencies, making installation easy. For Windows and Mac OS X, they should all be easy_install-able or at worst installable from the Python sources.

Built-in Web Server

Loggerhead has a built-in web server and when started with the serve-branches command, that web server is started on a default port listening on the localhost. If port 8080 (the default) is accessible on www.example.com, then running

$ serve-branches --host=www.example.com --port=8080 /srv/bzr

will list all of the available branches under that directory on http://www.example.com:8080/, so that the ProjectX trunk could be browsed at http://www.example.com:8080/projectx/trunk. Note that loggerhead provides HTTP access to the underlying Bazaar branches (similar to that described in Smart server over HTTP(S)), so this command should be run as a user without write privileges in /srv/bzr. By default, loggerhead only listens on the localhost, not any external ports, unless specified as above.

Behind a Proxy

A more common and more safe way to run loggerhead is behind another web server which will proxy certain requests to the loggerhead server on the localhost. To do this, you need to have PasteDeploy installed (see Requirements). Assuming that your server has Apache running, you need to add configuration such as this to set up the proxy

<Location "/loggerhead/">

If your proxy runs at some path within the server, then the serve-branches command must be started with the --prefix option. For this example, we could start loggerhead with the command

$ serve-branches --prefix=/loggerhead /srv/bzr

This would allow the trunk branch of ProjectX to be browsed at http://www.example.com/loggerhead/projectx/trunk.

Loggerhead comes with a script allowing it to run as a service on init.d based Unix systems. Contributions to do a similar thing on Windows servers would be welcomed at http://launchpad.net/loggerhead.

Other web interfaces

There are a number of other web interfaces available for Bazaar branches (see the list at http://wiki.bazaar.canonical.com/WebInterfaces) and we will just mention a couple of them here for their advantages in particular situations.

trac+bzr (http://launchpad.net/trac-bzr)
Trac is a popular web app that integrates a browser for branches, an issue tracker and a wiki. trac+bzr is a trac extension that allows for the trac to be used with Bazaar.
webbzr (http://thoughts.enseed.com/webbzr)
This is a notable solution because it is written in pure PHP for web hosts that don’t provide a way to run arbitrary Python applications such as Trac or Loggerhead.
Redmine (http://redmine.org/)
Like trac, Redmine is a full project management application using the Ruby on Rails framework. It includes support for Bazaar branches.

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