vSphere SDK for Perl Programming Guide - Documentation - VMware

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Refining vSphere SDK for Perl Scripts 3
This chapter discusses some programming techniques for your vSphere SDK for Perl scripts.
The chapter includes these topics:
“Creating and Using Filters” on page 33
“Filtering Views Selectively Using Properties” on page 35
“Retrieving the ServiceInstance Object on a vSphere Host” on page 36
“Saving and Using Sessions” on page 36
“Using Multiple Sessions” on page 37
“Learning About Object Structure Using Data::Dumper” on page 38
“Specifying Untyped Arguments in Scheduled Tasks and Callbacks” on page 39
“Using Advanced Subroutines” on page 40
Creating and Using Filters
You can use the vSphere SDK for Perl to define and use filters that select objects based on property values.
Filters can reduce a large result set to only those objects with characteristics of interest to you.
Using Filters with Vim::find_entity_view() or Vim::find_entity_views()
You can call Vim::find_entity_view() or Vim::find_entity_views() to retrieve objects from the
ESX/ESXi host. Vim::find_entity_view() returns the first object it finds that matches the search criteria.
Vim::find_entity_views() returns all objects.
When you call Vim::find_entity_view() the first object found might not be the one you are looking for. For
example, you might want to retrieve only those virtual machine objects whose names begin with a certain
prefix. When you call Vim::find_entity_views(), the command might return more objects than you want
to work with, for example all virtual machines in a datacenter. You can apply one or more filters to
Vim::find_entity_view() and Vim::find_entity_views() to select a subset of objects based on property
values.
To apply a filter to the results of Vim::find_entity_view() or Vim::find_entity_views(), you supply an
optional filter parameter. The value of the parameter is an anonymous hash reference containing one or
more pairs of filter criteria. Each of the criteria is a property path and a match value. The match value can be
either a string or a regular expression object. If the match value is a string, the value of the property must match
the string exactly (including case). To match Boolean values, use the strings true and false.
The following filter parameter matches a virtual machine power state of poweredOff:
filter => { 'runtime.powerState' => 'poweredOff' }
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