DownloadFile downloads the file at the given URL to the local filepath.

ExitErrorHandler exits the program with a non-zero exit status if err != nil.

GetInstanceName returns the name for an ec2.Instance.

GetTagValue iterates over the tags and returns the value of the given tag if it exists, otherwise "".

IsSubnetEmpty returns true/false depending on if the subnet is empty.

StringSliceContains returns true if the slice contains the string, otherwise false.

SubnetSize calculates the number of addresses in a given CIDR.