cluster: introduce NodeID and ZoneID types

Signed-off-by: Alejandro Mery <amery@jpi.io>

pkg/cluster/env.go

@@ -35,8 +35,8 @@ func (m *Cluster) Env(export bool) (*Env, error) {
 }
 
 // Zones returns the list of Zone IDs
-func (m *Env) Zones() []int {
-	var zones []int
+func (m *Env) Zones() []ZoneID {
+	var zones []ZoneID
 
 	m.ForEachZone(func(z *Zone) bool {
 		zones = append(zones, z.ID)
@@ -70,8 +70,8 @@ func (m *Env) WriteTo(w io.Writer) (int64, error) {
 		m.writeEnvVar(&buf, m.cephFSID, "FSID")
 	}
 
-	m.writeEnvVarStrings(&buf, m.Regions(), "REGIONS")
-	m.writeEnvVarInts(&buf, m.Zones(), "ZONES")
+	m.writeEnvVar(&buf, genEnvStrings(m.Regions()), "REGIONS")
+	m.writeEnvVar(&buf, genEnvInts(m.Zones()), "ZONES")
 
 	m.ForEachZone(func(z *Zone) bool {
 		m.writeEnvZone(&buf, z)
@@ -92,7 +92,7 @@ func (m *Env) writeEnvZone(w io.Writer, z *Zone) {
 
 	// ZONE{zoneID}_GW
 	gateways, _ := z.GatewayIDs()
-	m.writeEnvVarInts(w, gateways, "ZONE%v_%s", zoneID, "GW")
+	m.writeEnvVar(w, genEnvInts(gateways), "ZONE%v_%s", zoneID, "GW")
 
 	// ZONE{zoneID}_REGION
 	m.writeEnvVar(w, genEnvZoneRegion(z), "ZONE%v_%s", zoneID, "REGION")
@@ -155,6 +155,23 @@ func (m *Env) writeEnvVar(w io.Writer, value string, name string, args ...any) {
 	}
 }
 
+func genEnvInts[T ~int | ~uint](values []T) string {
+	var buf bytes.Buffer
+
+	for _, v := range values {
+		if buf.Len() > 0 {
+			_, _ = buf.WriteRune(' ')
+		}
+		_, _ = buf.WriteString(fmt.Sprintf("%v", v))
+	}
+
+	return buf.String()
+}
+
+func genEnvStrings(values []string) string {
+	return strings.Join(values, "")
+}
+
 func genEnvZoneNodes(z *Zone) string {
 	if n := z.Len(); n > 0 {
 		s := make([]string, 0, n)
@@ -164,7 +181,7 @@ func genEnvZoneNodes(z *Zone) string {
 			return false
 		})
 
-		return strings.Join(s, " ")
+		return genEnvStrings(s)
 	}
 	return ""
 }