Merge branch 'pr-amery-region-sort' into next-amery

pkg/cluster/regions.go

@@ -56,6 +56,7 @@ func (m *Cluster) initRegions(_ *ScanOptions) error {
 
 	// first regions defined by zones
 	m.ForEachZone(func(z *Zone) bool {
+		SortRegions(z.Regions)
 		for _, region := range z.Regions {
 			regions[region] = append(regions[region], z)
 		}
@@ -74,6 +75,7 @@ func (m *Cluster) initRegions(_ *ScanOptions) error {
 		m.finishRegion(r)
 	}
 
+	m.sortRegions()
 	return nil
 }
 

pkg/cluster/regions_utils.go

@@ -0,0 +1,41 @@
+package cluster
+
+import "sort"
+
+// SortRegions sorts regions. first by length those 3-character
+// or shorter, and then by length. It's mostly aimed at
+// supporting ISO-3166 order
+func SortRegions(regions []string) []string {
+	sort.Slice(regions, func(i, j int) bool {
+		r1, r2 := regions[i], regions[j]
+		return regionLess(r1, r2)
+	})
+
+	return regions
+}
+
+func regionLess(r1, r2 string) bool {
+	switch {
+	case len(r1) < 4:
+		switch {
+		case len(r1) < len(r2):
+			return true
+		case len(r1) > len(r2):
+			return false
+		default:
+			return r1 < r2
+		}
+	case len(r2) < 4:
+		return false
+	default:
+		return r1 < r2
+	}
+}
+
+func (m *Cluster) sortRegions() {
+	sort.Slice(m.Regions, func(i, j int) bool {
+		r1 := m.Regions[i].Name
+		r2 := m.Regions[j].Name
+		return regionLess(r1, r2)
+	})
+}