VM::EC2::Instance::State::Change - Represent an EC2 instance's change in state.

       Lincoln Stein <lincoln.stein@gmail.com>.

       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.

perl v5.38.2                                       2024-08-10              VM::EC2::Instance::State::Change(3pm)

       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",
                            "shutting-down".
        previousState   -- The instanceID's previous state AT THE TIME
                            THE STATECHANGE OBJECT WAS CREATED.

       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.

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

       VM::EC2::Instance::State::Change - Represent an EC2 instance's change in state.

       VM::EC2 VM::EC2::Generic VM::EC2::State VM::EC2::Instance

            # 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';