func (agent *ecsAgent) getHostPublicIPv4AddressFromEC2Metadata() string {
	// Get instance ID from ec2 metadata client.
	hostPublicIPv4Address, err := agent.ec2MetadataClient.PublicIPv4Address()
	if err != nil {
		seelog.Errorf("Unable to retrieve Host Instance PublicIPv4 Address: %v", err)
		return ""
	}
	return hostPublicIPv4Address
}
func (agent *ecsAgent) getHostPublicIPv4AddressFromEC2Metadata() string {
	// Get instance ID from ec2 metadata client.
	hostPublicIPv4Address, err := agent.ec2MetadataClient.PublicIPv4Address()
	if err != nil {
		seelog.Errorf("Unable to retrieve Host Instance PublicIPv4 Address: %v", err)
		return ""
	}
	return hostPublicIPv4Address
}
// getHostPublicIPv4AddressFromEC2Metadata will retrieve the PublicIPAddress (IPv4) of this
// instance through the EC2 API