Each LMIInstance in LMIShell represents a CIM instance provided by a certain provider.

Operations that can be performed within a LMIInstance:

  • get and set properties
  • list/print/execute its methods
  • print a documentation string
  • get a list of associated objects
  • get a list of association objects
  • push (update) a modified object to CIMOM
  • delete a single instance from the CIMOM.

Instance Methods

To get a list of methods, run following:

> instance.print_methods()
> method_lst = instance.methods()

To execute a method within an object, run this:

> instance.Method(
...    {"Param1" : value1,
...     "Param2" : value2, ...})
    errorstr="Possible error string"

NOTE: Instances do not auto-refresh after a method calls. It is necessary to perform this operation by hand (See Instance refreshing).

To get the result from a method call, see following:

> rval, rparams, errorstr = instance.Method(
...    {"Param1" : value1,
...     "Param2" : value2, ...})

The tuple in the previous example will contain return value of the method call (rval), returned parameters (rparams) and possible error string (errorstr).

Synchronous methods

LMIShell can perform synchronous method call, which means, that the LMIShell is able to synchronously wait for a Job object to change its state to Finished state and then return the job’s return parameters.

Most of the implemented methods in OpenLMI providers are asynchronous methods, which means that user can execute such method and do other desired actions while waiting for the result(s).

LMIShell can perform the synchronous method call, if the given method returns a object of following classes:

  • LMI_SELinuxJob
  • LMI_StorageJob
  • LMI_SoftwareInstallationJob
  • LMI_SoftwareVerificationJob
  • LMI_NetworkJob

LMIShell first tries to use indications as the waiting method. If it fails, then it uses polling method instead.

Following example illustrates, how to perform a synchronous method call:

> rval, rparams, errorstr = instance.SyncMethod(
...    {"Param1" : value1,
...     "Param2" : value2, ...})

NOTE: See the prefix Sync of a method name.

When a synchronous method call is done:

  • rval will contain the job’s return value
  • rparams will contain the job’s return parameters
  • errorstr will contain job’s possible error string

It is possible to force LMIShell to use only polling method, see the next example:

> rval, rparams, errorstr = instance.SyncMethod(
...    {"Param1" : value1,
...     "Param2" : value2, ...},
...    PreferPolling=True)

Signal handling

LMIShell can properly handle SIGINT and SIGTERM, which instruct the shell to cancel the synchronous call. When such signal is received, the background job, for which the LMIShell is waiting, will be asked to terminate, as well.

Instance Properties

To get a list of properties, see following:

> instance.print_properties()
> instance_prop_lst =

It is possible to access an instance object properties. To get a property, see the following example:

> instance.Property

To modify a property, execute following:

> instance.Property = NewPropertyValue
> instance.push()
LMIReturnValue(rval=0, rparams={}, errorstr="")

NOTE: If you change an instance object property, you have to execute a LMIInstance.push() method to propagate the change to the CIMOM.

ValueMap Parameters

A CIM Method may contain ValueMap parameters (aliases for constant values) in its MOF definition.

To access these parameters, which contain constant values, see following code:

> instance.Method.print_valuemap_parameters()
> valuemap_parameters = instance.Method.valuemap_parameters()

Get ValueMap parameter value

By using a ValueMap parameters, you can retrieve a constant value defined in the MOF file for a specific method.

To get a list of all available constants, their values, use the following code:

> instance.Method.ParameterValues.print_values()

NOTE: The suffix Values provides a way, how to access ValueMap parameters.

To retrieve a constant value, see the next example:

> constant_value_names_lst = instance.Method.ParameterValues.values()
> instance.Method.ParameterValues.ConstantValueName
> instance.Method.ParameterValues.value("ConstantValueName")

Get ValueMap parameter

Method can also contain a mapping between constant property name and corresponding value. Following code demonstrates, how to access such parameters:

> instance.Method.ConstantValueName

Get ValueMap parameter value name

LMIShell can also return string representing constant value. See the following code:

> instance.Method.ParameterValue.value_name(ConstantValue)

Instance refreshing

Local objects used by LMIShell, which represent CIM objects at CIMOM side, can get outdated, if such object changes while working with LMIShell’s one.

To update object’s properties, methods, etc. follow the next example:

> instance.refresh()
LMIReturnValue(rval=True, rparams={}, errorstr="")

Instance deletion

A single instance can be removed from the CIMOM by executing:

> instance.delete()

NOTE: After executing the LMIInstance.delete() method, all the object properties, methods will become inaccessible.

Deletion of the instance can be verified by:

> instance.is_deleted


For an instance object, you can also use a documentation method, which will display verbose information of its properties and values.

See next example:

> instance.doc()
# ... pretty verbose output displayed in a pages (can be modified by
#     setting environment variable PAGER) ...

MOF representation

An instance object can also print out its MOF representation. This can be achieved by running:

> instance.tomof()
... verbose output of the instance in MOF syntax ...

Useful Properties

Following part describes LMIInstance useful properties.

Class Name

Each instance object provide a property, that returns its class name. To get a string of the class name, run following:

> instance.classname


Each instance object also provides a property, that returns a namespace name. To get a string of the namespace name, run following:

> instance.namespace


To retrieve a unique, wrapped, identification object for the instance, LMIInstanceName, execute following:

> instance.path

Connection Object

This property returns a connection object, which was used to retrieve the instance (refer to Establish a connection). See next example:

> instance.connection
LMIConnection(URI='uri', user='user'...)

Wrapped Object

This property returns a wrapped wbem object. See the example:

> instance.wrapped_object
CIMInstance(classname=u'ClassName', ...)