GWM Developer Guide

This guide is intended to help you begin writing code and documentation for the Ganeti Web Manager project. Please read the OSL Development Process for information on how this project is managed and what we do to review and integrate code into the master repository. Please read the entire guide before beginning work, we will not be able to accept contributions that don’t follow these guidelines and standards.

For information on our release cycle and versions, please see Release Cycle .

Issue Tracking

The bug tracker for Ganeti Web Manager is at, and all bugs and feature requests for Ganeti Web Manager should be tracked there. Please create an issue for any code, documentation or translation you wish to contribute.

Please see Issues for details on how to create informative issues.

Dev Environment

Writing and testing code is made much easier by the right tools and a development environment that mirrors a production environment. To begin working with Ganeti Web Manager code, you will need Git, Python 2.6+, and Python VirtualEnv. We also recommend VirtualBox and Vagrant, a scripting front-end to VirtualBox to set up a virtual cluster to test your code with.


If you are unfamiliar with Git, please read the official Git tutorial or this excellent tutorial.

There are many Git GUIs, if you are not comfortable working with Git on the command line. See this list of Git GUI clients for more information.

Virtualenv and Pip

Ganeti Web Manager‘s install script uses the Python VirtualEnv utility to create a local environment in which to install all of GWM’s Python dependencies, and GWM itself runs from within this environment. To run tasks with, or to work with the python console on GWM code, you will need to activate the environment in your shell:

source /path/to/gwm/venv/bin/activate

Note that the environment will only be active for the terminal in which this command is run.

Pip is used to install packages to the currently active Python environment. If you would like to install python packages for debugging or to add functionality to Ganeti Web Manager, be sure the Ganeti Web Manager virtual environment is active and install packages:

pip install packagename

If you are adding python packages to add functionality or to support Ganeti Web Manager features you are adding, be sure to add the package to requirements.txt. You can get a list of all python packages installed in your current environment with

pip freeze

Add your package name to requirements.txt and commit this with the rest of your code. For more information on Pip and package name/version specifications, see (a link to pip docs)

VirtualBox and Vagrant

Virtual machines provide an easy way to deploy a Ganeti cluster to test Ganeti Web Manager with, or for use as a self-contained dev environment that can be shared with other developers. VirtualBox is a free virtualization platform available on Windows, Linux, and MacOS. Vagrant is a scripting front end for VirtualBox that allows easy creation, provisioning, and management of VirtualBox VMs, allowing developers to write and test their code in a uniform environment.


To install the GWM application for development work, please see Developer Installation.

Ganeti Web Manager ships with support for Vagrant. This allows developers to modify and test their code in the same environment and reduce the amount of configuration necessary. See Vagrant for details on setting up the virtual machine.

In addition, use of Ganeti Web Manager requires a Ganeti Cluster. For instructions on setting up a test cluster with Vagrant, see Vagrant Test Cluster.

Alternatively, Ganeti Web Manager now comes with a Dockerfile. This allows developers to use Docker to quickly run their code without needing to deal with setup and virtual machines. For now, the included Docker setup does not set up a Ganeti Cluster, for this, Vagrant is still needed.

To use Docker, simply build the included Dockerfile:

$ docker build -t="osuosl/ganeti_webmgr:dev" .

Then, just create a Docker container from the image:

$ docker run -it -p 8000:8000 osuosl/ganeti_webmgr:dev

Ganeti Web Manager can now be accessed on http://localhost:8000. To change the port that it runs on, the first number in the above command can be changed to the port of choice.

Some developers may prefer to mount their copy of the application as a volume when they run the app. This removes the need to rebuild the Docker image each time the code is changed, and can be done as follows:

$ docker run -v /path/to/code/:/opt/ganeti_webmgr -it -p 8000:8000 osuosl/whats_fresh:dev

Repository Layout

We loosely follow Git-flow for managing repository. Read about the branching model and why you may wish to use it too.

Releases only, this is the main public branch.
A release branch, the current release branch is tagged and merged into master.
Mostly stable development branch. Small changes only. It is acceptable that this branch have bugs, but should remain mostly stable.
feature/<issue number>
New features, these will be merged into develop when complete.
bug/<issue number>
Bug fixes.
enhancement/<issue number>
Enhancements to existing features.

See Issues for more information on issue types.

When working on new code, be sure to create a new branch from the appropriate place:

  • develop - if this is a new feature
  • release/<version> - if this is a bug fix on an existing release

Code Standards


We follow PEP 8, “the guide for python style”.

In addition to PEP 8:

  • Do not use backslash continuations. If a line must be broken up, use parenthetical continuations instead.


Write modular code. Focus on isolating units of code that can be easily analyzed and tested. For sanity purposes, please avoid mutually recursive objects.


If you need a JSON library, the import for this code base is “from django.utils import simplejson as json”. See #6579 for more information.


Ideally, tests should be written for all code that is submitted to the project. We recommend writing a test for any new feature before writing the code.

For bugs in features that have existing tests, be sure to run the existing tests on your code before submitting. In some cases a test will need to be updated or modified to test a bug fix, this should be done before writing code to fix the bug.

Tests can be submitted for features separate from the feature code itself, and feature requests that are submitted along with tests will be much more likely to be implemented.

See Running Tests for more information on writing unit tests for Ganeti Web Manager.

See Selenium test specs for some ideas on using the Selenium web testing framework to test GWM.

Adding features

When adding a feature to GWM, please remember to include:

Help tips

The gray box with a green title bar that appears on the right side of the page when you focus on a form field is a help tip. To add one for a new field, add it to the file which corresponds to your field’s form in the ganeti_web/templates/ganeti/helptips/ directory.


Ganeti Web Manager is designed to support translation to other languages using Django’s i18n machinery. If you add text that will be displayed to the user, please remember to format it for translation:

{% trans "this text will be displayed in the correct language" %}

{% blocktrans %}
    Here is a some text that will be displayed
    in the correct language but would not
    fit well in a single line
{% endblocktrans %}

Django’s i18n page has more information about this.

Fixing Bugs

When bugs are fixed, the issue should be updated with a clear description of the nature of the bug, the nature of the fix, and any additional notes that will help future developers understand the fix.

Before working on a bug fix, determine if the faulty code is covered by a unit test. If so, and the test did not reveal the flaw, update the test appropriately. If no test exists, it should be written if possible. The test should be submitted along with the fixed code.

Writing Documentation

Documentation exists as RestructuredText files within the GWM repository, and as in-line comments in the source code itself.


The docs/ directory contains the full tree of documentation in RestructuredText format. To generate the docs locally, make sure you have activated the Ganeti Web Manager virtual environment, and that Sphinx is installed.

pip install -r requirements/docs.txt
cd docs
make html

HTML documentation will be generated in the build/html directory. For information on generating other formats, see the Sphinx documentation.

The documentation for Ganeti Web Manager is divided into several sections:

  • Features: Descriptions of features and their implementation
  • User Guide: How to use GWM and its various features
  • Development Guide: How to work on the GWM code (this document)
  • Info: Various information on the project itself
  • Reference: General information referred to in other docs

Usage of features should be documented in the usage/ directory. Each distinct unit of functionality should have a separate file, for instance “create a new virtual machine” should have a single file documenting how to create a new virtual machine. Overview documents, for example “managing virtual machines” will reference or include these sub files.

Implementation and structural details of features should be documented in the features/ directory, one file per distinct feature. This documentation should give an overview of the functionality, rational and implementation of the feature - for example, documenting how the “add virtual machine” view generates a request to the RAPI.

Any changes or enhancements to an existing feature should be documented in the feature’s documentation files.

Development documentation should be updated when any changes are made to the development process, standards, or implementation strategies.

In-line Docs

All methods in the source code should be commented with doc strings, including parameters, return values, and general functionality.

Submitting Code

Please read OSL Development Process for details on how we triage, review and merge contributed code.


Patches should either be attached to issues, or emailed to the mailing list. If a patch is relevant to an issue, then please attach the patch to the issue to prevent it from getting lost.

Patches must be in git patch format, as generated by git format-patch.

git commit
git format-patch HEAD^

To create patches for all changes made from the origin’s master branch, try:

git format-patch origin/master

For more information, see the man page for git-format-patch.

Sending emails to the list can be made easier with git send-mail; see the man page for git-send-email for instructions on getting your email system to work with git.

Pull Requests

If there are multiple patches comprising a series which should be applied all at once, git pull requests are fine. Send a rationale for the pull request, along with a git pull URL and branch name, to the mailing list.

Git Write Access

Contributors in good standing who have contributed significant patches and who have shown a long-term commitment to the project may be given write access to our repository. Such contributors must follow our OSL Development Process, including participating in code review and planning.

Submitting Documentation

Documentation is just as much a part of the project as code, and as such you can contribute documentation just as outlined above for code. See Writing Documentation for details on the documentation tree.

If you are not comfortable with git, patches or pull requests, you may submit documentation via a text file sent to the mailing list or attached to an issue. We recommend creating an issue, as this helps us keep track of contributions, but the mailing list is an excellent place to solicit feedback on your work.

Submitting Translations

Translations should be submitted via patches, a pull request, or by attaching a .po file to an issue. We recommend cloning the git repository and using makemessages to find all the available strings for translation. If you find strings in the UI that are not available for translation, patches to fix this condition are much appreciated. As with all contributions, we recommend creating a new issue on our issue tracker for your work.

For details on how to write translation strings and how to make use of them, please see Django’s i18n page