address feedback

cloud/scope/managedcontrolplane.go

@@ -21,6 +21,8 @@ import (
 	"fmt"
 	"strings"
 
+	"sigs.k8s.io/cluster-api-provider-gcp/util/location"
+
 	"google.golang.org/api/option"
 
 	"sigs.k8s.io/cluster-api/util/conditions"
@@ -209,8 +211,8 @@ func parseLocation(location string) string {
 
 // Region returns the region of the GKE cluster.
 func (s *ManagedControlPlaneScope) Region() string {
-	region := parseLocation(s.GCPManagedControlPlane.Spec.Location)
-	return region
+	loc, _ := location.Parse(s.GCPManagedControlPlane.Spec.Location)
+	return loc.Region
 }
 
 // ClusterLocation returns the location of the cluster.

cloud/scope/managedmachinepool.go

@@ -20,6 +20,8 @@ import (
 	"context"
 	"fmt"
 
+	"sigs.k8s.io/cluster-api-provider-gcp/util/location"
+
 	"google.golang.org/api/option"
 	"sigs.k8s.io/cluster-api/util/conditions"
 
@@ -208,8 +210,8 @@ func (s *ManagedMachinePoolScope) NodePoolName() string {
 
 // Region returns the region of the GKE node pool.
 func (s *ManagedMachinePoolScope) Region() string {
-	region := parseLocation(s.GCPManagedControlPlane.Spec.Location)
-	return region
+	loc, _ := location.Parse(s.GCPManagedControlPlane.Spec.Location)
+	return loc.Region
 }
 
 // NodePoolLocation returns the location of the node pool.

util/location/location.go

@@ -0,0 +1,50 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package location implements location parsing utilities.
+package location
+
+import (
+	"strings"
+
+	"github.com/pkg/errors"
+)
+
+// Location captures the region and zone of a GCP location.
+// Examples of GCP location:
+// us-central1 (region).
+// us-central1-c (region with zone).
+type Location struct {
+	Region string
+	Zone   *string
+}
+
+// Parse parses a location string.
+func Parse(location string) (Location, error) {
+	parts := strings.Split(location, "-")
+	if len(parts) < 2 {
+		return Location{}, errors.New("invalid location")
+	}
+	region := strings.Join(parts[:2], "-")
+	var zone *string
+	if len(parts) == 3 {
+		zone = &parts[2]
+	}
+	return Location{
+		Region: region,
+		Zone:   zone,
+	}, nil
+}