1. Introduction¶
Chapter Contents
1.1. Functionality¶
Pywbem supports the following functionality:
-
This API supports issuing WBEM operations to a WBEM server, using the CIM operations over HTTP (CIM-XML) protocol defined in the DMTF standards DSP0200 and DSP0201.
-
This API encapsulates certain functionality of a WBEM server for use by a WBEM client application, such as determining the Interop namespace of the server, or the management profiles advertised by the server.
-
This API supports starting and stopping a WBEM listener that waits for indications (i.e. events) emitted by a WBEM server using the CIM-XML protocol. The API also supports managing subscriptions for such indications.
-
This API provides for invoking the MOF compiler and for plugging in your own CIM repository into the MOF compiler.
-
Pywbem includes a few utility commands:
-
A MOF compiler that takes MOF files as input and updates the CIM repository of a WBEM server with the result. See DSP0004 for a definition of MOF.
-
A WBEM client in the form of a shell that provides an interactive Python environment for issuing WBEM operations to a WBEM server.
-
1.2. Installation¶
Pywbem is a pure Python package and therefore does not have a dependency on operating system packages in addition to Python itself. However, some of the Python packages used by pywbem have dependencies on additional operating system packages for their installation. Also, on some platforms, manual post-processing steps are needed, such as setting up environment variables.
This section describes the complete installation of pywbem with all steps including prerequisite operating system packages and manual post-processing steps, for users of pywbem. As a user of pywbem, you can import the pywbem Python package into your programs, and/or you can run the WBEM utility commands that come with pywbem.
If you want to contribute to the pywbem project, you need to set up a development and test environment for pywbem. That has a larger set of OS-level prerequisites and its setup is described in chapter Development.
A note on the pywbem_os_setup.sh
script that is used for installation on
some platforms: That script installs the Python distro
package into the
active Python environment. If your active Python environment is a virtual
Python environment, that package will obviously be installed into that virtual
environment. If your active Python environment is the system Python
environment, that package will be installed into the system Python, but as a
local package for the current user. So it is not visible in the system Python
of other users, but still visible in the system Python of the current user.
This is done in order not to pollute the system Python installation with
additional Python packages that are not known at the OS-level package manager
(e.g. yum
on RedHat) and thus may be considered a maintenance problem.
1.2.1. Supported environments¶
Pywbem is supported in these environments:
- Operating Systems: Linux, Windows (native, and with UNIX-like environments), OS-X
- Python: 2.6, 2.7, 3.4, and higher
- WBEM servers: Any WBEM server that conforms to the DMTF specifications listed in Standards conformance. WBEM servers supporting older versions of these standards are also supported, but may have limitations. See WBEM servers for more details.
Limitations:
- On Windows (native), pywbem is not supported on Python 2.6, because the M2Crypto package does not support Python 2.6.
Announcement of removal of Python 2.6 support:
- The Python Software Foundation has stopped supporting Python 2.6 with the 2.6.9 release in october 2013. Since then, many Python package projects have continued releasing versions for Python 2.6, and so has pywbem. In 2017 and 2018, a number of Python package projects have actively removed support for Python 2.6 and it has become an increasingly difficult task for pywbem to keep supporting Python 2.6. For this reason, Python 2.6 support will be removed from pywbem in its future 1.0.0 version.
1.2.2. Installing to Linux¶
Prerequisites:
- The Python environment into which you want to install must be the current
Python environment, and must have at least the following Python packages
installed:
- setuptools
- wheel (<0.30.0 on Python 2.6)
- pip
- The Python environment into which you want to install must be the current
Python environment, and must have at least the following Python packages
installed:
Download the
pywbem_os_setup.sh
script from one of these sources:pywbem_os_setup.sh
on this site- pywbem_os_setup.sh on the master branch of the pywbem Git repository
That script installs OS-level prerequisite packages needed by pywbem.
Execute the
pywbem_os_setup.sh
script:$ ./pywbem_os_setup.sh
The script uses
sudo
under the covers to invoke the OS-level package manager for your Linux distribution (e.g.yum
on the RedHat family), so the current userid needs to have sudo permission.On older Linux versions, the Swig utility may not be available in the required version. In that case, the
pywbem_os_setup.sh
script will report that as an issue and one option on how to proceed is to build Swig yourself as described in Building Swig, and then to repeat execution of thepywbem_os_setup.sh
script.In case the script reports that your Linux distribution is not supported by the script, you can still try to find out what the corresponding OS-level packages are on your Linux distribution and install them manually. The script will list the names and versions of the OS-level packages for RedHat in that case, and you would need to find out what the corresponding packages are on your desired Linux distribution. If you were able to find these packages, please open an issue so we can add support for that Linux distribution to the script.
Only on Python 2.6 on Linux Debian family systems with multi-architecture support (e.g. Ubuntu 16.04 and higher):
Perform the following workaround to make the multi-architecture header files of OpenSSL available in a compatible way (the example is for x86_64 systems):
$ sudo ln -s /usr/include/x86_64-linux-gnu/openssl/opensslconf.h /usr/include/openssl/opensslconf.h
Background: One of the packages needed by pywbem on Python 2 is
M2Crypto
. During its own installation as a Python package,M2Crypto
needs the OpenSSL header files. On Linux Debian family systems with multi-architecture support, the structure of OpenSSL header files changed incompatibly (compared to earlier versions of these distributions). The installation ofM2Crypto
tries to accomodate that incompatibility by detecting multi-architecture support, but on Python 2.6 the interface for that was not yet supported. As a result, the OpenSSL header files are not found. The workaround established in this step makes the OpenSSL header files available in a compatible way, so that theM2Crypto
installation finds them.Install pywbem (and its prerequisite Python packages) into the active Python environment:
$ pip install pywbem
1.2.3. Installing to OS-X¶
Prerequisites:
- The Python environment into which you want to install must be the current
Python environment, and must have at least the following Python packages
installed:
- setuptools
- wheel (<0.30.0 on Python 2.6)
- pip
- The Python environment into which you want to install must be the current
Python environment, and must have at least the following Python packages
installed:
Download the
pywbem_os_setup.sh
script from one of these sources:pywbem_os_setup.sh
on this site- pywbem_os_setup.sh on the master branch of the pywbem Git repository
That script installs OS-level prerequisite packages needed by pywbem.
Execute the
pywbem_os_setup.sh
script:$ ./pywbem_os_setup.sh
The script uses
sudo
under the covers to invokebrew
(Homebrew project) to install OS-level packages, so the current userid needs to have sudo permission.Only on Python 2 on newer OS-X releases:
The
pywbem_os_setup.sh
script installs theopenssl
package needed by theM2Crypto
Python package. On newer OS-X releases, you may see a notice that theopenssl
package is “not linked” because the TLS implementation provided with OS-X is available. In that case, you need to set up the following environment variables for use by the pywbem package installation described in the next step:$ openssl_dir=$(brew --prefix openssl) $ export LDFLAGS="-L$openssl_dir/lib $LDFLAGS" $ export CFLAGS="-I$openssl_dir/include $CFLAGS" $ export SWIG_FEATURES="-I$openssl_dir/include $SWIG_FEATURES"
Install pywbem (and its prerequisite Python packages) into the active Python environment:
$ pip install pywbem
1.2.4. Installing to native Windows¶
This section describes the installation of pywbem into a native Windows environment. That is an environment where the Windows command processor is used to run any commands. Tools from UNIX-like environments may or may not be present in the PATH.
Prerequisites:
- The Python environment into which you want to install must be the active
Python environment, and must have at least the following Python packages
installed:
- setuptools
- wheel
- pip
- Windows command prompt in administrator mode.
- The Python environment into which you want to install must be the active
Python environment, and must have at least the following Python packages
installed:
Download the
pywbem_os_setup.bat
script from one of these sources:pywbem_os_setup.bat
on this site- pywbem_os_setup.bat on the master branch of the pywbem Git repository
Execute the
pywbem_os_setup.bat
script in a Windows command prompt in administrator mode:> pywbem_os_setup.bat
This script checks whether the commands needed for installing and using pywbem are available in the PATH. If not, it installs them via the Chocolatey package manager.
The following commands are needed for installing and using pywbem:
swig
curl
grep
chmod
tar
These commands can be made available in the PATH via a UNIX-like environment such as CygWin, MSYS2, Babun, or Gow. If they are not all available in the PATH, the Chocolatey package manager must be installed and its
choco
command must be available in the PATH.This script will also install the
M2Crypto
Python package into the active Python environment, so it must be run with the desired Python environment active.This script will also download and install Win32 OpenSSL from https://slproweb.com/products/Win32OpenSSL.html.
Install pywbem (and its other prerequisite Python packages) into the active Python environment by running in a Windows command prompt in administrator mode:
> pip install pywbem
1.2.5. Installing to a UNIX-like environment under Windows¶
This section describes the installation of pywbem into a UNIX-like environment
under Windows (such as CygWin, MSYS2, Babun, or Gow). That is an
environment where the UNIX/Linux shell of the UNIX-like environment (such as
bash
or sh
) is used to run any commands.
Note that Unix-like environments on Windows bring their own Python, so in such an environment, you install into that Python, and not into the Python of Windows.
Prerequisites:
The Python environment into which you want to install must be the current Python environment, and must have at least the following Python packages installed:
- setuptools
- wheel (<0.30.0 on Python 2.6)
- pip
Prerequisite OS-level packages must be available in the UNIX-like environment.
For CygWin, these packages can be installed using the CygWin setup program and are listed in Prerequisite operating system packages for install.
For other UNIX-like environments, we did not compile a list of the required packages. If you can help out here by providing the package names, please tell us by opening an issue).
Install pywbem (and its other prerequisite Python packages) into the active Python environment, by running in the UNIX/Linux shell of the UNIX-like environment:
$ pip install pywbem
If the Swig compilation during installation of
M2Crypto
fails, there may be components of the UNIX-like environment missing (see first item).
1.2.6. Installing into a different Python environment¶
The examples in the previous sections install pywbem and its prerequisite Python packages using the Pip utility. By default, Pip installs these packages into the currently active Python environment. That can be the system Python, or a virtual Python. The commands shown above did not detail this, but this section does.
If you just want to use the scripts that come with pywbem, and want them to be always available without having to think about activating virtual Python environments, then installation of pywbem into the system Python environment is probably the right choice for you. If your intention is to write code against the pywbem APIs, installation into a virtual Python environment is recommended.
An additional dimension is Python 2 vs. Python 3:
- On systems where Python 2 is the default, the
python
andpip
commands operate on Python 2. There may bepython3
andpip3
commands that operate on Python 3. - On some newer systems (e.g. Ubuntu 17.04), Python 3 is the default. In that
case, the
python
andpip
commands operate on Python 3. There may bepython2
andpip2
commands that operate on Python 2.
For simplicity, the following examples show only the default commands.
To install pywbem into the currently active virtual Python environment (e.g.
myenv
), issue:(myenv)$ pip install pywbem
To install pywbem for only the current user into the currently active system Python environment, issue:
$ pip install --user pywbem
This installs the Python packages in a directory under the home directory of the current user and therefore does not require sudo permissions nor does it modify the system Python environment seen by other users.
To install pywbem for all users into the currently active system Python environment, issue:
$ sudo pip install pywbem
This installs the Python packages into a directory of the system Python installation and therefore requires sudo permissions.
Be aware that this may replace the content of existing packages when a package version is updated. Such updated packages as well as any newly installed packages are not known by your operating system installer, so the knowledge of your operating system installer is now out of sync with the actual set of packages in the system Python.
Therefore, this approach is not recommended and you should apply this approach only after you have thought about how you would maintain these Python packages in the future.
1.2.7. Installing a different version of pywbem¶
The examples in the previous sections install the latest version of pywbem that is released on PyPI. This section describes how different versions of pywbem can be installed.
To install the latest version of pywbem that is released on PyPI, issue:
$ pip install pywbem
To install an older released version of pywbem, Pip supports specifying a version requirement. The following example installs pywbem version 0.10.0 from PyPI:
$ pip install pywbem==0.10.0
If you need to get a certain new functionality or a new fix of pywbem that is not yet part of a version released to PyPI, Pip supports installation from a Git repository. The following example installs pywbem from the current code level in the master branch of the pywbem Git repository:
$ pip install git+https://github.com/pywbem/pywbem.git@master#egg=pywbem
1.2.8. Verifying the installation¶
You can verify that pywbem is installed correctly by importing the package into Python (using the Python environment you installed pywbem to):
$ python -c "import pywbem; print('ok')"
ok
In case of trouble with the installation, see the Troubleshooting section.
1.2.9. Prerequisite operating system packages for install¶
The following table lists the prerequisite operating system packages along with their version requirements for installing and running pywbem, for the supported operating systems and Linux distributions. This list is for reference only, because the installation steps in the previous sections already take care of getting these packages installed.
The prerequisite operating system packages for developing pywbem are not listed in this table; you can find them in section Prerequisite operating system packages for development.
Op.system / Distribution | Package name | Version requirements | Notes |
---|---|---|---|
Linux RedHat family (RHEL, CentOS, Fedora) | openssl-devel | >=1.0.1 | py2 |
python-devel | for your Python 2.x | py2 | |
gcc-c++ | >=4.4 | py2 | |
swig | >=2.0 | py2 | |
Linux Debian family (Ubuntu, Debian, LinuxMint) | libssl-dev | >=1.0.1 | py2 |
python-dev | for your Python 2.x | py2 | |
g++ | >=4.4 | py2 | |
swig | >=2.0 | py2 | |
Linux SUSE family (SLES, openSUSE) | openssl-devel | >=1.0.1 | py2 |
python-devel | for your Python 2.x | py2 | |
gcc-c++ | >=4.4 | py2 | |
swig | >=2.0 | py2 | |
OS-X | openssl | >=1.0.1 | py2 |
gcc | >=4.4 | py2 | |
swig | >=2.0 | py2 | |
Windows (native) | None | ||
Windows (CygWin) | openssl-devel | py2 | |
python2-devel | py2 | ||
gcc-g++ | py2 | ||
swig | py2 |
Notes:
- py2: Only needed with Python 2 (not needed with Python 3).
1.2.10. Building Swig¶
The installation of M2Crypto needs the Swig utility (e.g. swig
package
on RedHat). On some Linux distributions, the Swig utility is not available in
the required version. In such cases, it can be built from its sources, as
follows:
Install the PCRE development packages:
pcre-devel
package on Linux RedHat and SUSE familieslibpcre3
andlibpcre3-dev
packages on Linux Debian family
Download the source archive of Swig version 2.0 or higher, and unpack it. For example, using Swig version 2.0.12:
$ wget -q -O swig-2.0.12.tar.gz https://sourceforge.net/projects/swig/files/swig/swig-2.0.12/swig-2.0.12.tar.gz/download $ tar -xf swig-2.0.12.tar.gz
Configure and build Swig:
$ cd swig-2.0.12 $ ./configure --prefix=/usr $ make swig
Install Swig (for all users of the system):
$ sudo make install
Verify the installation and the version of Swig:
$ swig -version SWIG Version 2.0.12
1.3. Package version¶
Since pywbem 0.8.1, the version of the pywbem package can be accessed by
programs using the pywbem.__version__
variable:
-
pywbem._version.
__version__
= '0.13.1'¶ The full version of this package including any development levels, as a string.
Possible formats for this version string are:
- “M.N.P.devNNN”: Development level NNN of a not yet released assumed M.N.P version
- “M.N.P”: A released M.N.P version
Note: For tooling reasons, the variable is shown as
pywbem._version.__version__
, but it should be used as
pywbem.__version__
.
From earlier versions of pywbem, pywbem 0.7.0 was the only version released to Pypi, and most likely also the only version that was packaged as an operating system package into Linux distributions.
The following shell command can be used to determine the version of pywbem, for all versions that were released to Pypi, and independently of whether pywbem was installed as an operating system package or as a Python package:
python -c "\
import pywbem, os, subprocess; \
fs=os.path.join(os.path.dirname(pywbem.__file__),'setup.py'); \
vs=subprocess.check_output(['python',fs,'--version']).strip() \
if os.path.exists(fs) else None; \
v=getattr(pywbem, '__version__', vs if vs else '0.7.0-assumed'); \
print(v) \
"
1.4. Standards conformance¶
The pywbem client and pywbem indication listener conform to the following CIM and WBEM standards, in the version specified when following the links to the standards:
The implementation of the CIM-XML protocol in pywbem (client and listener) conforms to DSP0200 and DSP0201.
Limitations:
- The mock support of pywbem (see Mock support) does not support the
ModifyClass
operation. Note that in its implementation of the CIM-XML protocol, pywbem does support theModifyClass
operation. - The
EnumerationCount
operation is not supported by pywbem. That operation is optional for WBEM servers to support, and is hard to implement reasonably. - Multi-requests are not supported by pywbem. This is not a functional limitation though, because the use of multi-requests is entirely determined by the client: If a client does not use multi-requests, the server does not use multi-responses.
Notes:
- The CIM-XML representation as defined in DSP0201 supports CIM methods that have a void return type. However, the CIM architecture defined in DSP0004 does not support that, and neither does pywbem.
- The CIM-XML representation as defined in DSP0201 supports references to CIM classes. However, the CIM architecture defined in DSP0004 does not support that, and neither does pywbem.
- The mock support of pywbem (see Mock support) does not support the
The CIM-XML representation of CIM objects as produced by their
tocimxml()
andtocimxmlstr()
methods conforms to the representations for these objects as defined in DSP0201.Limitations:
- The xml:lang attribute supported by DSP0201 on some CIM-XML elements that can have string values is tolerated in the CIM-XML received by pywbem, but is ignored and is not represented on the corresponding CIM objects.
The capabilities of CIM objects conform to the CIM architecture as defined in DSP0004.
The MOF as produced by the
tomof()
methods on CIM objects and as parsed by the MOF compiler conforms to the MOF syntax as defined in DSP0004.Limitations:
- The pywbem MOF compiler has the restriction that CIM instances specified in MOF that have an alias must have key properties that are either initialized in the instance, or have non-NULL default values (issue #1079).
- The pywbem MOF compiler has the restriction that an alias must be defined before it is used. In the MOF syntax defined in DSP0004, no such restriction exists (issue #1078).
- The pywbem MOF compiler does not roll back changes to qualifier declarations when it aborts (issue #990).
The WBEM URIs produced by the
to_wbem_uri()
methods ofCIMInstanceName
andCIMClassName
conform to the WBEM URI syntax as defined in DSP0207.Note that the
__str__()
methods of these two classes produce strings that are similar but not conformant to DSP0207, for historical reasons.The mechanisms for discovering the Interop namespace of a WBEM server and the management profiles advertised by a WBEM server and their central instances in the WBEM server API conform to DSP1033.
The mechanisms for subscribing for CIM indications in the WBEM indication API conform to DSP1054.
1.5. Deprecation and compatibility policy¶
Since version 0.7.0, pywbem attempts to be as backwards compatible as possible.
Compatibility of pywbem is always seen from the perspective of the user of the pywbem APIs or pywbem utility commands. Thus, a backwards compatible new version of pywbem means that a user can safely upgrade to that new version without encountering compatibility issues for their code using the pywbem APIs or for their scripts using the pywbem utility commands.
Having said that, there is always the possibility that even a bug fix changes some behavior a user was dependent upon. Over time, the pywbem project has put automated regression testing in place that tests the behavior at the APIs, but such compatibility issues cannot be entirely excluded.
Pywbem uses the rules of Semantic Versioning 2.0.0 for compatibility between versions, and for deprecations. The public interface that is subject to the semantic versioning rules and specificically to its compatibility rules are the various pywbem APIs described in this documentation, and the command line interface of the pywbem utility commands.
Occasionally functionality needs to be retired, because it is flawed and a better but incompatible replacement has emerged. In pywbem, such changes are done by deprecating existing functionality, without removing it immediately. The deprecated functionality is still supported at least throughout new minor or update releases within the same major release. Eventually, a new major release may break compatibility by removing deprecated functionality.
Any changes at the pywbem APIs or utility commands that do introduce incompatibilities as defined above, are described in the Change log.
Deprecation of functionality at the pywbem APIs or utility commands is communicated to the users in multiple ways:
- It is described in the documentation of the API or utility command
- It is mentioned in the change log.
- It is raised at runtime by issuing Python warnings of type
DeprecationWarning
(see the Pythonwarnings
module).
Since Python 2.7, DeprecationWarning
messages are suppressed by default.
They can be shown for example in any of these ways:
- By specifying the Python command line option:
-W default
- By invoking Python with the environment variable:
PYTHONWARNINGS=default
It is recommended that users of the pywbem package run their test code with
DeprecationWarning
messages being shown, so they become aware of any use of
deprecated functionality.
Here is a summary of the deprecation and compatibility policy used by pywbem, by release type:
- New update release (M.N.U -> M.N.U+1): No new deprecations; no new functionality; backwards compatible.
- New minor release (M.N.U -> M.N+1.0): New deprecations may be added; functionality may be extended; backwards compatible.
- New major release (M.N.U -> M+1.0.0): Deprecated functionality may get removed; functionality may be extended or changed; backwards compatibility may be broken.
1.6. Python namespaces¶
The external APIs of pywbem are defined by the symbols in the pywbem
namespace. That is the only Python namespace that needs to be imported by
users.
With pywbem versions prior to v0.8, it was common for users to import the
sub-modules of pywbem (e.g. pywbem.cim_obj
). The sub-modules that existed
prior to v0.8 are still available for compatibility reasons.
Starting with v0.8, the pywbem
namespace was cleaned up, and not all public
symbols available in the sub-module namespaces are available in the pywbem
namespace anymore. The symbols in the sub-module namespaces are still available
for compatibility, including those that are no longer available in the
pywbem
namespace. However, any use of symbols from the sub-module namespaces
is deprecated starting with v0.8, and you should assume that a future version of
pywbem will remove them. If you miss any symbol you were used to use, please
open an issue.
New sub-modules added since pywbem v0.8 have a leading underscore in their name in order to document that they are considered an implementation detail and that they should not be imported by users.
With pywbem versions prior to v0.11, the MOF compiler API was only
available in the pywbem.mof_compiler
namespace. Starting with pywbem
version v0.11, it is also available in the pywbem
namespace and should be
used from there.
This documentation describes only the external APIs of pywbem, and omits any internal symbols and any sub-modules.
1.7. Configuration variables¶
Pywbem supports a very limited number of configuration variables that influence certain specific behavior.
These configuration variables can be modified by the user directly after importing pywbem. For example:
import pywbem
pywbem.config.ENFORCE_INTEGER_RANGE = False
Note that the pywbem source file defining these variables should not be changed by the user. Instead, the technique shown in the example above should be used to modify the configuration variables.
-
pywbem.config.
ENFORCE_INTEGER_RANGE
= True¶ Enforce the allowable value range for CIM integer types (e.g.
Uint8
). For details, see theCIMInt
base class.- True (default): Pywbem enforces the allowable value range; Assigning
values out of range causes
ValueError
to be raised. - False: Pywbem does not enforce the allowable value range; Assigning values out of range works in pywbem. Note that a WBEM server may or may not reject such out-of-range values.
New in pywbem 0.9.
- True (default): Pywbem enforces the allowable value range; Assigning
values out of range causes
-
pywbem.config.
DEFAULT_ITER_MAXOBJECTCOUNT
= 1000¶ Default setting for the MaxObjectCount attribute for all of the
WBEMConnection
:Iter… operations. If this attribute is not specified on a request such asIterEnumerateInstances()
, this value will be used as the value for MaxObjectCount. Note that this does not necessarily optimize the performance of these operations.New in pywbem 0.10 as experimental and finalized in 0.12.
-
pywbem.config.
SEND_VALUE_NULL
= True¶ Backwards compatibility option controlling the use of VALUE.NULL for representing NULL entries in array values in CIM-XML requests sent to WBEM servers.
DSP0201 requires the use of VALUE.NULL for representing NULL entries in array values since its version 2.2 (released 01/2007). Pywbem added support for using VALUE.NULL in CIM-XML requests in its version 0.12. In case a WBEM server has not implemented support for VALUE.NULL, this config option can be used to disable the use of VALUE.NULL as a means for backwards compatibility with such WBEM servers.
Note that the config option only influences the behavior of pywbem for using VALUE.NULL in CIM-XML requests sent to a WBEM server. Regardless of the config option, pywbem will always support VALUE.NULL in CIM-XML responses the pywbem client receives from a WBEM server, and in CIM-XML requests the pywbem listener receives from a WBEM server.
- True (default): Pywbem uses VALUE.NULL in CIM-XML requests for representing NULL entries in array values.
- False: Pywbem uses VALUE with an empty value in CIM-XML requests for representing NULL entries in array values.
New in pywbem 0.12.
-
pywbem.config.
IGNORE_NULL_KEY_VALUE
= False¶ Backward compatibility option that controls creating
CIMInstanceName
objects with NULL values for keybindings.DSP0004, section 7.9 specifically forbids key properties with values that are NULL but because pywbem has always allowed this, adding the code to disallow None as a keybinding value is an incompatible change.
- True: Pywbem tolerates None as a value when keybindings are defined.
- False (default): Pywbem raises ValueError when keybindings are created where any key will have the value None.
New in pywbem 0.12.
-
pywbem.config.
AUTO_GENERATE_SFCB_UEP_HEADER
= True¶ Option that enables or disables the automatic creation of a special HTTP header field that the Small Footprint CIM Broker (SFCB) requires when invoking its special “UpdateExpiredPassword()” method. See https://sblim.sourceforge.net/wiki/index.php/SfcbExpiredPasswordUpdate for details.
- True: (default): Automatic creation is enabled, and pywbem will create
the HTTP header field
Pragma: UpdateExpiredPassword
in all CIM-XML requests that invoke a CIM method named “UpdateExpiredPassword()”. - False: Automatic creation is disabled.
New in pywbem 0.13.
- True: (default): Automatic creation is enabled, and pywbem will create
the HTTP header field
1.8. WBEM servers¶
1.8.1. Server-specific features¶
Pywbem supports the following features of some specific WBEM servers that are additions to the DMTF standards:
- OpenPegasus
- Pywbem supports the Interop namespace
root/PG_InterOp
that is specific to OpenPegasus. OpenPegasus also supports the standard Interop namespaces (interop
,root/interop
) but for backwards compatibility with earlier versions of OpenPegasus, pywbem supports this old Interop namespace, for example in its Interop namespace determination whose result is exposed in thepywbem.WBEMServer.interop_ns
property. - Pywbem supports the upper-case variant
EMBEDDEDOBJECT
of the respective CIM-XML attribute that is specific to some releases of OpenPegasus, in addition to the mixed-case variantEmbeddedObject
that is defined in the DSP0201 standard and that is also supported by OpenPegasus. Older releases of OpenPegasus supported only the upper-case variant. - Pywbem supports a connection to an OpenPegasus server using Unix Domain
Sockets through its
PegasusUDSConnection
subclass ofWBEMConnection
.
- Pywbem supports the Interop namespace
- SFCB (Small Footprint CIM Broker)
- Pywbem supports a connection to an SFCB server using Unix Domain
Sockets through its
SFCBUDSConnection
subclass ofWBEMConnection
.
- Pywbem supports a connection to an SFCB server using Unix Domain
Sockets through its
- OpenWBEM
- Pywbem supports the OWlocal authentication extension of OpenWBEM, which is a password-less local authorization.
- Pywbem supports a connection to an OpenWBEM server using Unix Domain
Sockets through its
OpenWBEMUDSConnection
subclass ofWBEMConnection
.
1.8.2. WBEM server testing¶
Today the pywbem project tests primarily against current versions of the OpenPegasus WBEM server because that server is available to the project.
These tests are captured in the test script run_cimoperations.py
. Note that
generally those tests that are server-specific only run against the defined
server so that there are a number of tests that run only against the
OpenPegasus server. This includes some tests that use specific providers
in the OpenPegasus server to set up tests such as indication tests.