func getNEGZones()

in projects/k8s-hybrid-neg-controller/pkg/config/zones.go [86:121]

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

func getNEGZones(ctx context.Context, logger logr.Logger, projectID string, regionZonesClient *compute.RegionZonesClient) ([]string, error) {
	var zones []string
	var err error
	switch {
	case len(negZonesFlag) > 0:
		// Use the values from the supplied `neg-zones` flag.
		zones = strings.Split(negZonesFlag, ",")
	case len(zoneMappingFlag) > 0:
		// Use the target values from the `zone-mapping` flag.
		zoneMapping := parseZoneMappingFlag()
		for _, negZone := range zoneMapping {
			zones = append(zones, negZone)
		}
	case metadata.OnGCE():
		// Look up zones from the Compute Engine or Google Kubernetes Engine metadata server, and
		// using the Compute Engine API.
		// 1. Look up the zone of the current Kubernetes Node from the metadata server.
		// 2. Determine the region of that zone.
		// 3. Use the Compute Engine API to list the zones of that region.
		logger.V(4).Info("No NEG zones provided, attempting to fetch zones from the metadata server")
		zones, err = lookupNEGZones(ctx, projectID, regionZonesClient)
		if err != nil {
			return nil, err
		}
	}
	if len(zones) == 0 {
		return nil, errAtLeastOneZoneRequired
	}
	slices.Sort(zones)
	for _, zone := range zones {
		if !isValidNEGZone(zone) {
			return nil, fmt.Errorf("%w zone=%s", errInvalidNEGZone, zone)
		}
	}
	return zones, nil
}