4. Pywbemcli special command line features

Pywbemcli includes several features in the command syntax that are worth presenting in detail to help the user understand the background, purpose and syntactic implementation of the features. This includes:

  • The ability to receive either CIM instances or classes or only their names with only a change of an option on the commands that request CIM instances or classes. The --names-only/-no command option defines whether only the name or the complete object will be displayed.
  • The ability to define complete INSTANCE name command arguments or interactively select the instance namesfrom a list presented by pywbemcli for certain objects rather than typing in long names the full name. see Specifying the INSTANCENAME command argument.

4.1. pywbemcli commands to WBEM operations

The following table defines which pywbemcli commands are used for the corresponding WBEM operations.

WBEM CIM-XML Operation pywbemcli command group & command
Instance Operations:  
EnumerateInstances instance enumerate INSTANCENAME
EnumerateInstanceNames instance enumerate INSTANCENAME –names-only
GetInstance instance get INSTANCENAME
ModifyInstance instance modify
CreateInstance instance create
DeleteInstance instance delete INSTANCENAME
Associators(instance) instance associators INSTANCENAME
Associators(class) class associators CLASSNAME
AssociatorNames(instance) instance associators INSTANCENAME –names-only
AssociatorNames(class) class associators CLASSNAME –names-only
References(instance) instance references INSTANCENAME
References(class) class references CLASSNAME
ReferenceNames(instance) instance references INSTANCENAME –names-only
ReferenceNames(class) class references CLASSNAME –names-only
InvokeMethod instance invokemethod INSTANCENAME –names-only
ReferenceNames class invokemethod CLASSNAME –names-only
ExecQuery instance query
Pull Operations: Option –use-pull either or yes
OpenEnumerateInstances instance enumerate INSTANCENAME
OpenEnumerateInstancePaths instance enumerate INSTANCENAME –names-only
OpenAssociatorInstances instance associators INSTANCENAME
OpenAssociatorInstancePaths instance associators INSTANCENAME –names-only
OpenReferenceInstances instance references INSTANCENAME
OpenReferenceInstancePaths instance references INSTANCENAME –names-only
OpenQueryInstances instance references INSTANCENAME –names-only
PullInstancesWithPath part of pull sequence
PullInstancePaths part of pull sequence
PullInstances part of pull sequence
CloseEnumeration Not implemented
Class Operations:  
EnumerateClasses class enumerate CLASSNAME
EnumerateClassNames class enumerate –names-only
GetClass class get CLASSNAME
ModifyClass Not implemented
CreateClass Not implemented
DeleteClass class delete CLASSNAME
QualifierDeclaration ops:  
EnumerateQualifiers qualifier enumerate
GetQualifier qualifier get QUALIFIERNAME
SetQualifier Not implemented
DeleteQualifier Not Implemented

4.2. Specifying CIM property and parameter values

The Instance create command, Instance modify command, Class invokemethod command, and Instance invokemethod command define the values of properties and parameters that are to be applied to CIM instances and methods to be sent to the WBEM server.

For a single property or parameter this is the --property/-p or --parameter/-p option with the name and value in the form:

-p <name>=<value>

Where:

  • <name> is the name of the of the property or parameter.
  • <value> is the value of the property or parameter The values represent the value of CIM types (ex. Uint32, String, etc.) or arrays of these types.
value := scalarValue | or arrayValues
arrayValues := scalarValue [ "," scalarValue]
scalarValue := integerValue, realValue, charValue, stringValue,
               datetimeValue, booleanValue, nullValue, objectPath of
               ANNEX A :term:`DSP0004`

These values define the syntax of the values to build CIM properties and CIM parameters to be sent to the CIM Server. Since the WBEM server requires that each property/parameter be typed to be created, pywbemcli retrieves the target CIM class from the WBEM Server to determine the CIM type and arrayness required to define a CIMProperty.

The scalarValues limitations with respect to the definitions in DSP0004 include:

  • Only decimal integers are allowed (octal, hex, and binary are not supported).
  • Integers must be in the value range of the corresponding CIM type (ex. Uint32) defined in the class to which the property is being applied.
  • The format for objectPath is the WBEM URI as defined in Specifying the INSTANCENAME command argument

Quotes around the value are only required if the value includes whitespace. See backslash-escaped for information on use of backslashes in formating property and parameter argument values.

The following are examples of scalar property definitions:

  -p p1=SomeText
  -p p2=\"Text with space\"
  -p pint=3
  -p psint=-3

For array properties the values are defined separated by commas:

.. code-block:: text

  -p <property-name>=<value>(,<value>)

For example:

.. code-block:: text

  -p strarray=abc,def,ghjk
  -p strarray2=\"ab c\",def

4.3. Displaying CIM instances/classes or their names

The pywbem API includes different WBEM operations (ex. EnumerateInstances, EnumerateInstanceNames, EnumerateClasses, and EnumerateClassNames) to request CIM objects or just their names. To simplify the overall command line syntax pywbemcli combines these into a single command (i.e. enumerate, references, associators) in the Class command group and the Instance command group and includes an option (--no, or --names-only) that determines whether the names or the CIM objects are retrieved from the WBEM server.

Thus, for example an instance enumerate with and without the --names-only option:

$ pywbemcli --mock-server tests/unit/simple_mock_model.mof instance enumerate CIM_Foo

instance of CIM_Foo {
   InstanceID = "CIM_Foo1";
   IntegerProp = 1;
};

instance of CIM_Foo {
   InstanceID = "CIM_Foo2";
   IntegerProp = 2;
};

instance of CIM_Foo {
   InstanceID = "CIM_Foo3";
};

$ pywbemcli --mock-server tests/unit/simple_mock_model.mof instance enumerate CIM_Foo --names-only

root/cimv2:CIM_Foo.InstanceID="CIM_Foo1"
root/cimv2:CIM_Foo.InstanceID="CIM_Foo2"
root/cimv2:CIM_Foo.InstanceID="CIM_Foo3"

4.4. Specifying the INSTANCENAME command argument

The INSTANCENAME argument used by some pywbemcli commands (e.g instance get) specifies the instance path (aka instance name) of a CIM instance in a CIM namespace of a WBEM server.

The instance name (INSTANCENAME argument) can be specified in two ways:

  • By specifying a complete untyped WBEM URI as defined in section The INSTANCENAME command argument as a WBEM URI. The namespace of the instance is the namespace specified in the WBEM URI, or the namespace specified with the -namespace/-n command option, or the default namespace of the connection. Any host name in the WBEM URI will be ignored.
  • By specifying the WBEM URI with the wildcard “?” in place of the keys component of the WBEM URI, as defined in section Interactively selecting INSTANCENAME command argument (i.e. CLASSNAME.?). The namespace of the instance is the namespace specified with the -namespace/-n command option, or the default namespace of the connection.

4.4.1. The INSTANCENAME command argument as a WBEM URI

The format used by pywbemcli for specifying complete INSTANCENAME arguments on the command line is an untyped WBEM URI for instance paths as defined in DSP0207, this is the standard format. There is also a historical format for WBEM URIs that is described in the pywbem.CIMInstanceName.to_wbem_uri() method.

The INSTANCENAME argument can be specified using the standard format or the historical format.

Because pywbemcli always works with a single WBEM server at a time, the authority component of the WBEM URI does not need to be specified in an INSTANCENAME argument. Because the namespace type of the WBEM URI (e.g. “http” or “https”) is not relevant for identifying the CIM instance, the namespace type does not need to be specified in an INSTANCENAME argument.

With these simplifications and using the (simpler) historical format, the format for the INSTANCENAME argument can be described by the following ABNF:

INSTANCENAME = [ NAMESPACE ":" ] CLASSNAME [ "." keybindings ]

keybindings = keybinding *( "," keybinding )

keybinding = PROPERTYNAME "=" value

value = integerValue / charValue / stringValue / datetimeValue / booleanValue / referenceValue

referenceValue = "\"" escaped_INSTANCENAME "\""

where:

  • NAMESPACE, CLASSNAME and PROPERTYNAME are namespace, class and key property name, respectively, as used elsewhere in pywbemcli.

    The namespace, if specified, must be the target namespace of the operation. The purpose of being able to specify a namespace in INSTANCENAME is not to override the target namespace, but to use returned instance names that may contain a namespace, unchanged.

  • integerValue, charValue, stringValue, datetimeValue and booleanValue are defined in ANNEX A of DSP0004.

    Note that stringValue and datetimeValue when used in INSTANCENAME have exactly one set of surrounding double quotes (i.e. they cannot be constructed via string concatenation).

    Note that charValue when used in INSTANCENAME has exactly one set of surrounding single quotes.

    Note that DSP0004 prevents the use of real32 or real64 typed properties as keys.

  • escaped_INSTANCENAME is a backslash-escaped INSTANCENAME where at least backslash and double quote characters are backslash-escaped

Examples for UNIX-like shells. See backslash-escaped for information on use of backslashes:

pywbemcli instance get root/cimv2:MY_Foo.ID=42
pywbemcli instance get MY_Foo.ID=42
pywbemcli instance get "MY_Foo.CharKey='x'"
pywbemcli instance get 'MY_Foo.InstanceID="foo1"'
pywbemcli instance get "MY_Foo.InstanceID=\"$value\""
pywbemcli instance get 'MY_CS.CreationClassName="MY_CS",Name="MyComp"'
pywbemcli instance get 'MY_LogEntry.Timestamp="20190901183853.762122+120"'

Examples for Windows command processor:

pywbemcli instance get root/cimv2:MY_Foo.ID=42
pywbemcli instance get MY_Foo.ID=42
pywbemcli instance get MY_Foo.CharKey='x'
pywbemcli instance get MY_Foo.InstanceID="foo1"
pywbemcli instance get MY_Foo.InstanceID="%value%"
pywbemcli instance get MY_CS.CreationClassName="MY_CS",Name="MyComp"
pywbemcli instance get MY_LogEntry.Timestamp="20190901183853.762122+120"

4.4.2. Interactively selecting INSTANCENAME command argument

To simplify creating the INSTANCENAME argument on the command line, pywbemcli provides a wildcard character “?” that can be used in the INSTANCENAME argument in place of the keybindings component of the WBEM URI.

If an INSTANCENAME argument specifies the wildcard key, pywbemcli performs an interactive selection of the instance name by enumerating the instance names of the specified class, displaying the list of instance names along with index numbers, and prompting the user for the index number of the instance name to be used.

The ABNF for the INSTANCENAME argument with a wildcard key is:

INSTANCENAME = CLASSNAME "." wildcard

wildcard = "?"

where:

  • CLASSNAME is a class name as used elsewhere in pywbemcli.

Thus, in place of the full WBEM URI (ex. CIM_Foo.InstanceID="CIM_Foo1"), the user specifies CIM_Foo.? for the INSTANCENAME argument to trigger the interactive selection, as shown in the following example:

$ pywbemcli --mock-server tests/unit/simple_mock_model.mof instance get CIM_Foo.?
Pick Instance name to process
0: root/cimv2:CIM_Foo.InstanceID="CIM_Foo1"
1: root/cimv2:CIM_Foo.InstanceID="CIM_Foo2"
2: root/cimv2:CIM_Foo.InstanceID="CIM_Foo3"
Input integer between 0 and 2 or Ctrl-C to exit selection: 0  << user enters 0
instance of CIM_Foo {
   InstanceID = "CIM_Foo1";
   IntegerProp = 1;
};