VM::EC2::Instance::State::Change(3) Represent an EC2 instance's change in state.


# find all stopped instances
@instances = $ec2->describe_instances(-filter=>{'instance-state-name'=>'stopped'});
# start them
@state_change = $ec2->start_instances(@instances)

foreach my $sc (@state_change) {
my $instanceId = $sc->instanceId;
my $currentState = $sc->currentState;
my $previousState = $sc->previousState;
# poll till the first instance is running
sleep 2 until $state_change[0]->current_status eq 'running';


This object represents a state change in an Amazon EC2 instance. It is returned by VM::EC2 start_instances(), stop_instances(), terminate_instances(), reboot_instances() and the corresponding VM::EC2::Instance methods. In addition, this object is returned by calls to VM::EC2::Instance->instanceState().


These object methods are supported:

 instanceId      -- The instanceId.
 currentState    -- The instanceId's current state AT THE TIME
                     THE STATECHANGE OBJECT WAS CREATED. One of
                     "terminated", "running", "stopped", "stopping",
 previousState   -- The instanceID's previous state AT THE TIME

Note that currentState and previousState return a VM::EC2::Instance::State object, which provides both string-readable forms and numeric codes representing the state.

In addition, the method provides the following convenience method:

$state = $state_change->current_status()

This method returns the current state of the instance. This is the correct method to call if you are interested in knowing what the instance is doing right now.


In a string context, the method will return the string representation of currentState.


Lincoln Stein <[email protected]>.

Copyright (c) 2011 Ontario Institute for Cancer Research

This package and its accompanying libraries is free software; you can redistribute it and/or modify it under the terms of the GPL (either version 1, or at your option, any later version) or the Artistic License 2.0. Refer to LICENSE for the full license text. In addition, please see DISCLAIMER.txt for disclaimers of warranty.