vSphere SDK for Perl Programming Guide - Documentation - VMware

vSphere SDK for Perl Programming Guide
Omitting Optional Arguments in Method Calls
When you call a vSphere API method using vSphere SDK for Perl, and want to omit an optional argument,
you can do one of two things:
You can omit the argument:
$vm->PowerOnVM(host => $host); # with the optional host argument
$vm->PowerOnVM(); # without the optional host argument
You can supply undef as the value of the optional argument:
$vm->PowerOnVM(host => undef);
Supplying undef as the value of the optional argument is useful when the value of an argument, which might
or might not be undef, is contained in a variable, as in the following example:
my $host = Vim::find_entity_view(
view_type => 'HostSystem',
filter => { name => 'preferredHost' }
);
$vm->PowerOnVM(host => $host);
You cannot use the empty string or the value 0 to represent undef or an unset parameter.
Updating View Objects
In any view, the values of the view properties represent the state of the server‐side objects at the time the view
was created. These property values are not updated automatically. In a production environment, the state of
managed objects on the server is likely to change frequently. If your client script depends on the server being
in a particular state (poweredOn or poweredOff, for example), then you can refresh the view object’s state. You
can use the vSphere SDK for Perl Vim::update_view_data() subroutine to refresh the values of client‐side
views with server‐side values. Example 2‐3 uses Vim::update_view_data() to refresh view data.
Example 2-3. Updating the State of View Objects
#!/usr/bin/perl
use strict;
use warnings;
use VMware::VIRuntime;
. . .
# Get all VirtualMachine objects
my $vm_views = Vim::find_entity_views(view_type => 'VirtualMachine');
# Power off virtual machines.
foreach my $vm (@$vm_views) {
# Refresh the state of each view
$vm->update_view_data();
if ($vm->runtime->powerState->val eq 'poweredOn') {
$vm->PowerOffVM();
print " Stopped virtual machine: " . $vm->name . "\n";
} else {
print " Virtual machine " . $vm->name .
" power state is: " . $vm->runtime->powerState->val . "\n";
}
}
32 VMware, Inc.