10. Development

This section only needs to be read by developers of the pywbem package. People that want to make a fix or develop some extension, and people that want to test the project are also considered developers for the purpose of this section.

10.1. Repository

The repository for pywbem is on GitHub:


10.2. Setting up the development environment

It is recommended to use Linux as the development environment for pywbem. OS-X should work as well, but Windows requires a number of manual setup steps.

  1. Clone the Git repo of this project and switch to its working directory:

    $ git clone git@github.com:pywbem/pywbem.git
    $ cd pywbem
  2. It is recommended that you set up a virtual Python environment. Have the virtual Python environment active for all remaining steps.

  3. Install pywbem and its prerequisites for installing and running it as described in Installation. This will install Python packages into the active Python environment, and OS-level packages.

  4. On Windows, perform the setup steps described in Manual setup on Windows. On Linux and OS-X, the corresponding setup is performed automatically as part of the next step.

  5. Install the prerequsites for pywbem development. This will install Python packages into the active Python environment, and OS-level packages:

    $ make develop
  6. This project uses Make to do things in the currently active Python environment. The command:

    $ make

    displays a list of valid Make targets and a short description of what each target does.

10.2.1. Manual setup on Windows

For development of pywbem, it is recommended to use one of the Unix-like environments on Windows (such as CygWin, MinGW, Babun, or Gow). The pywbem tests that run on the Appveyor CI use CygWin.

Note that Unix-like environments on Windows bring their own Python, so double check that the active Python environment is the one you want to install to.

The development environment needs the xmllint utility and the lxml Python package.

The lxml Python package for Windows meanwhile comes as a binary wheel archive that includes all of its dependencies, so it has no additional dependencies you would need to take care about.

The xmllint utility is part of CygWin and likely also part of the other Unix-like environments.

10.3. Prerequisite operating system packages for development

The following table lists the prerequisite operating system packages along with their version requirements for development of pywbem, for the supported operating systems and Linux distributions.

The prerequisite operating system packages for installing and running pywbem are also needed for development, and can be found in section Prerequisite operating system packages for install.

This section is just for information. These packages will be installed as part of the steps described in Setting up the development environment.

Op.system / Distribution Package name Version requirements Notes
Linux RedHat family (RHEL, CentOS, Fedora)      
Linux Debian family (Ubuntu, Debian, LinuxMint)      
Linux SUSE family (SLES, openSUSE)      
Windows xmllint    

10.4. Building the documentation

The ReadTheDocs (RTD) site is used to publish the documentation for the pywbem package at https://pywbem.readthedocs.io/

This page is automatically updated whenever the Git repo for this package changes the branch from which this documentation is built.

In order to build the documentation locally from the Git work directory, execute:

$ make builddoc

The top-level document to open with a web browser will be build_doc/html/docs/index.html.

10.5. Testing

All of the following make commands run the tests in the currently active Python environment. Depending on how the pywbem package is installed in that Python environment, either the pywbem and pywbem_mock directories in the main repository directory are used, or the installed pywbem package. The test case files and any utility functions they use are always used from the tests directory in the main repository directory.

The tests directory has the following subdirectory structure:

 +-- unittest            Unit tests
 |    +-- utils               Utility functions used by unit tests
 |    +-- pywbem              Unit tests for the pywbem package
 |    +-- pywbem_mock         Unit tests for the pywbem_mock package
 |    +-- unittest_utils      Unit tests for tests/unittest/utils
 |    +-- functiontest        Unit tests for tests/functiontest
 |    +-- end2endtest_utils   Unit tests for tests/end2endtest/utils
 |    +-- servers             Unit tests for tests/servers
 +-- functiontest        Function tests
 +-- end2endtest         End2end tests
 |    +-- utils               Utility functions used by end2end tests
 +-- manualtest          Manual tests
 +-- server_definitions  WBEM server definition file used by some tests and module
 |                         for accessing it
 +-- profiles            Simple definitions of management profiles used by some tests
 +-- schema              The CIM schema MOF files used by some MOF tests
 +-- dtd                 The CIM DTD file used by some CIM-XML validation tests

There are multiple types of tests in pywbem:

  1. Unit tests and function tests

    These tests do not require any WBEM server to be available, and the tests validate their results automatically.

    The distinction between unit tests and function tests as used in pywbem is that function tests exercise the entire pywbem client component or entire pywbem scripts, while unit tests exercise single modules.

    They are run by executing:

    $ make test

    Test execution can be modified by a number of environment variables, as documented in the make help (execute make help).

  2. End2end tests

    These tests are run against one or more WBEM servers, and the tests validate their results automatically.

    They are run by preparing a server definition file:


    from the provided example, and by executing:

    $ make end2end

    Again, test execution can be modified by a number of environment variables, as documented in the make help (execute make help).

  3. Manual tests

    There are several Python scripts and shell scripts that can be run manually. The results need to be validated manually.

    These scripts are in the directory:


    and are executed by simply invoking them from within the main directory of the repository, e.g.:


    Some of the scripts support a –help option that informs about their usage.

    The run_cim_operations.py script needs a particular MOF file loaded in the repository of the WBEM server that is used for the test. This can be done using the MOF compiler of pywbem:

    $ mof_compiler -s <target_url> tests/unittest/pywbem/test.mof

To run the unit and function tests in all supported Python environments, the Tox tool can be used. It creates the necessary virtual Python environments and executes make test (i.e. the unit and function tests) in each of them.

For running Tox, it does not matter which Python environment is currently active, as long as the Python tox package is installed in it:

$ tox                              # Run tests on all supported Python versions
$ tox -e py27                      # Run tests on Python 2.7

10.6. Updating the DMTF MOF Test Schema

Pywbem uses DMTF CIM Schemas in its CI testing. The schema used is stored in the form received from the DMTF in the directory tests/schema and is expanded and compiled as part of the unit tests.

Since the DMTF regularly updates the schema, the pywbem project tries to stay up-to-date with the current schema. At the same time, earlier schemas can be used for testing also by changing the definitions for the dmtf schema to be tested.

The schema used for testing can be modified by modifying the test file:


10.7. Developing PyWBEM Ipython Documentation Notebooks

The pywbem developers are using ipython notebooks to demonstrate the use of pywbem. Today we generally have one notebook per operation or group of operations including definition of the operation, references back to the pywbem documentation, and one or more examples (hopefully examples that will actually execute against a wbem server)

These can easily be extended or supplemented using a local ipython or jupyter server by:

1. Install ipython or Jupyter software using pip or pip3. The notebook server may be installed as root or within a python virtual environment. For example:

$ sudo pip install ipython
$ sudo pip3 install ipython
$ sudo pip install jupyter

The notebook server may be installed as root or within a python virtual environment.

2. Start the local ipython/jupyter notebook server in the notebook directory (pywbem/docs/notebooks) referencing that directory in the command line call:

$ ipython notebook docs/notebooks
$ jupyter notebook docs/notebooks

This will start the local ipython/juypter notebook server and on the first page displayed in your web browser all existing pywbem ipython notebooks will be available for editing. New ones can be created using the commands on that ipython server web page.

New and changed notebooks must go through the same contribution process as other components of pywbem to be integrated into the github repository.

10.8. Contributing

Third party contributions to this project are welcome!

In order to contribute, create a Git pull request, considering this:

  • Test is required.
  • Each commit should only contain one “logical” change.
  • A “logical” change should be put into one commit, and not split over multiple commits.
  • Large new features should be split into stages.
  • The commit message should not only summarize what you have done, but explain why the change is useful.
  • The commit message must follow the format explained below.

What comprises a “logical” change is subject to sound judgement. Sometimes, it makes sense to produce a set of commits for a feature (even if not large). For example, a first commit may introduce a (presumably) compatible API change without exploitation of that feature. With only this commit applied, it should be demonstrable that everything is still working as before. The next commit may be the exploitation of the feature in other components.

For further discussion of good and bad practices regarding commits, see:

10.9. Core Development Team

Anyone can contribute to pywbem via pull requests as described in the previous section.

The pywbem project has a core development team that holds regular web conferences and that is using Slack for offline communication, on the Slack workspace: https://pywbem.slack.com.

The web conference and the Slack workspace are by invitation, and if you want to participate in the core team, please open an issue to let us know.