zones: assign zoneID to zones inferable ID

Signed-off-by: Alejandro Mery <[email protected]>

pkg/zones/scan.go

@@ -5,6 +5,20 @@ import (
 )
 
 func (m *Zones) scan() error {
+	for _, fn := range []func() error{
+		m.scanDirectory,
+		m.scanMachines,
+		m.scanZoneIDs,
+	} {
+		if err := fn(); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (m *Zones) scanDirectory() error {
 	// each directory is a zone
 	entries, err := fs.ReadDir(m.dir, ".")
 	if err != nil {
@@ -26,7 +40,7 @@ func (m *Zones) scan() error {
 		}
 	}
 
-	return m.scanMachines()
+	return nil
 }
 
 func (m *Zones) scanMachines() error {
@@ -38,6 +52,36 @@ func (m *Zones) scanMachines() error {
 	return err
 }
 
+func (m *Zones) scanZoneIDs() error {
+	var hasMissing bool
+	var lastZoneID int
+
+	m.ForEachZone(func(z *Zone) bool {
+		switch {
+		case z.ID == 0:
+			hasMissing = true
+		case z.ID > lastZoneID:
+			lastZoneID = z.ID
+		}
+
+		return false
+	})
+
+	if hasMissing {
+		next := lastZoneID + 1
+
+		m.ForEachZone(func(z *Zone) bool {
+			if z.ID == 0 {
+				z.ID, next = next, next+1
+			}
+
+			return false
+		})
+	}
+
+	return nil
+}
+
 func (z *Zone) scan() error {
 	// each directory is a machine
 	entries, err := fs.ReadDir(z.zones.dir, z.Name)