use GetInstanceProviderID to get instance provider ID

staging/src/k8s.io/legacy-cloud-providers/gce/BUILD

@@ -97,6 +97,7 @@ go_test(
         "gce_annotations_test.go",
         "gce_disks_test.go",
         "gce_healthchecks_test.go",
+        "gce_instances_test.go",
         "gce_loadbalancer_external_test.go",
         "gce_loadbalancer_internal_test.go",
         "gce_loadbalancer_metrics_test.go",

staging/src/k8s.io/legacy-cloud-providers/gce/gce_instances.go

@@ -264,7 +264,10 @@ func (g *Cloud) InstanceExists(ctx context.Context, node *v1.Node) (bool, error)
 	providerID := node.Spec.ProviderID
 	if providerID == "" {
 		var err error
-		if providerID, err = g.InstanceID(ctx, types.NodeName(node.Name)); err != nil {
+		if providerID, err = cloudprovider.GetInstanceProviderID(ctx, g, types.NodeName(node.Name)); err != nil {
+			if err == cloudprovider.InstanceNotFound {
+				return false, nil
+			}
 			return false, err
 		}
 	}
@@ -279,7 +282,7 @@ func (g *Cloud) InstanceMetadata(ctx context.Context, node *v1.Node) (*cloudprov
 	providerID := node.Spec.ProviderID
 	if providerID == "" {
 		var err error
-		if providerID, err = g.InstanceID(ctx, types.NodeName(node.Name)); err != nil {
+		if providerID, err = cloudprovider.GetInstanceProviderID(ctx, g, types.NodeName(node.Name)); err != nil {
 			return nil, err
 		}
 	}

staging/src/k8s.io/legacy-cloud-providers/gce/gce_instances_test.go

@@ -0,0 +1,69 @@
+// +build !providerless
+
+/*
+Copyright 2020 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 gce
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+func TestInstanceExists(t *testing.T) {
+	gce, err := fakeGCECloud(DefaultTestClusterValues())
+	require.NoError(t, err)
+
+	nodeNames := []string{"test-node-1"}
+	_, err = createAndInsertNodes(gce, nodeNames, vals.ZoneName)
+	require.NoError(t, err)
+
+	testcases := []struct {
+		name        string
+		nodeName    string
+		exist       bool
+		expectedErr error
+	}{
+		{
+			name:        "node exist",
+			nodeName:    "test-node-1",
+			exist:       true,
+			expectedErr: nil,
+		},
+		{
+			name:        "node not exist",
+			nodeName:    "test-node-2",
+			exist:       false,
+			expectedErr: fmt.Errorf("failed to get instance ID from cloud provider: instance not found"),
+		},
+	}
+
+	for _, test := range testcases {
+		t.Run(test.name, func(t *testing.T) {
+			node := &v1.Node{ObjectMeta: metav1.ObjectMeta{Name: test.nodeName}}
+			exist, err := gce.InstanceExists(context.TODO(), node)
+			assert.Equal(t, test.expectedErr, err, test.name)
+			assert.Equal(t, test.exist, exist, test.name)
+		})
+	}
+}

staging/src/k8s.io/legacy-cloud-providers/gce/gce_loadbalancer_utils_test.go

@@ -94,6 +94,8 @@ func createAndInsertNodes(gce *Cloud, nodeNames []string, zoneName string) ([]*v
 					Tags: &compute.Tags{
 						Items: []string{name},
 					},
+					// add Instance.Zone, otherwise InstanceID() won't return a right instanceID.
+					Zone: zoneName,
 				},
 			)
 			if err != nil {