func getAwsRegionFromZones()

in plugins/aws_ebs.go [277:302]

• 21 lines of code
• 9 McCabe index (conditional complexity)

func getAwsRegionFromZones(zones []string) (string, error) {
	regions := sets.String{}
	if len(zones) < 1 {
		return "", fmt.Errorf("no zones specified")
	}

	// AWS zones can be in four forms:
	// us-west-2a, us-gov-east-1a, us-west-2-lax-1a (local zone) and us-east-1-wl1-bos-wlz-1 (wavelength).
	for _, zone := range zones {
		splitZone := strings.Split(zone, "-")
		if (len(splitZone) == 3 || len(splitZone) == 4) && len(splitZone[len(splitZone)-1]) == 2 {
			// this would break if we ever have a location with more than 9 regions, ie us-west-10.
			splitZone[len(splitZone)-1] = splitZone[len(splitZone)-1][:1]
			regions.Insert(strings.Join(splitZone, "-"))
		} else if len(splitZone) == 5 || len(splitZone) == 7 {
			// local zone or wavelength
			regions.Insert(strings.Join(splitZone[:3], "-"))
		} else {
			return "", fmt.Errorf("Unexpected zone format: %v is not a valid AWS zone", zone)
		}
	}
	if regions.Len() != 1 {
		return "", fmt.Errorf("multiple or no regions gotten from zones, got: %v", regions)
	}
	return regions.UnsortedList()[0], nil
}