From 897f8012fdd3739ebbb726c8356b91552ad26f84 Mon Sep 17 00:00:00 2001
From: navist2020 <navist2020@163.com>
Date: Thu, 3 Jun 2021 17:56:19 +0800
Subject: [PATCH] kubeadm:Run preflight checks for diff to check that the
 manifests already exist

---
 cmd/kubeadm/app/cmd/upgrade/diff.go      | 28 +++++++++++-
 cmd/kubeadm/app/cmd/upgrade/diff_test.go | 57 ++++++++++++++++++++++++
 2 files changed, 84 insertions(+), 1 deletion(-)

diff --git a/cmd/kubeadm/app/cmd/upgrade/diff.go b/cmd/kubeadm/app/cmd/upgrade/diff.go
index 500d176f5a9..bb9a2c3a7cd 100644
--- a/cmd/kubeadm/app/cmd/upgrade/diff.go
+++ b/cmd/kubeadm/app/cmd/upgrade/diff.go
@@ -19,6 +19,7 @@ package upgrade
 import (
 	"io"
 	"io/ioutil"
+	"os"
 
 	"github.com/pkg/errors"
 	"github.com/pmezard/go-difflib/difflib"
@@ -65,7 +66,13 @@ func newCmdDiff(out io.Writer) *cobra.Command {
 		Use:   "diff [version]",
 		Short: "Show what differences would be applied to existing static pod manifests. See also: kubeadm upgrade apply --dry-run",
 		RunE: func(cmd *cobra.Command, args []string) error {
-			// TODO: Run preflight checks for diff to check that the manifests already exist.
+			// Run preflight checks for diff to check that the manifests already exist.
+			if err := validateManifestsPath(
+				flags.apiServerManifestPath,
+				flags.controllerManagerManifestPath,
+				flags.schedulerManifestPath); err != nil {
+				return err
+			}
 			return runDiff(flags, args)
 		},
 	}
@@ -80,6 +87,25 @@ func newCmdDiff(out io.Writer) *cobra.Command {
 	return cmd
 }
 
+func validateManifestsPath(manifests ...string) (err error) {
+	for _, manifestPath := range manifests {
+		if len(manifestPath) == 0 {
+			return errors.New("empty manifest path")
+		}
+		s, err := os.Stat(manifestPath)
+		if err != nil {
+			if os.IsNotExist(err) {
+				return errors.Wrapf(err, "the manifest file %q does not exist", manifestPath)
+			}
+			return errors.Wrapf(err, "error obtaining stats for manifest file %q", manifestPath)
+		}
+		if s.IsDir() {
+			return errors.Errorf("%q is a directory", manifestPath)
+		}
+	}
+	return nil
+}
+
 func runDiff(flags *diffFlags, args []string) error {
 	var err error
 	var cfg *kubeadmapi.InitConfiguration
diff --git a/cmd/kubeadm/app/cmd/upgrade/diff_test.go b/cmd/kubeadm/app/cmd/upgrade/diff_test.go
index f67eae8f878..4f71f83cdf9 100644
--- a/cmd/kubeadm/app/cmd/upgrade/diff_test.go
+++ b/cmd/kubeadm/app/cmd/upgrade/diff_test.go
@@ -124,3 +124,60 @@ func TestRunDiff(t *testing.T) {
 		})
 	}
 }
+
+func TestValidateManifests(t *testing.T) {
+	// Create valid manifest paths
+	apiServerManifest, err := createTestRunDiffFile([]byte{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.Remove(apiServerManifest)
+	controllerManagerManifest, err := createTestRunDiffFile([]byte{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.Remove(controllerManagerManifest)
+	schedulerManifest, err := createTestRunDiffFile([]byte{})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.Remove(schedulerManifest)
+	// Create a file path that does not exist
+	notExistFilePath := "./foobar123456"
+
+	testCases := []struct {
+		name          string
+		args          []string
+		expectedError bool
+	}{
+		{
+			name:          "valid: valid manifest path",
+			args:          []string{apiServerManifest, controllerManagerManifest, schedulerManifest},
+			expectedError: false,
+		},
+		{
+			name:          "invalid: one is empty path",
+			args:          []string{apiServerManifest, controllerManagerManifest, ""},
+			expectedError: true,
+		},
+		{
+			name:          "invalid: manifest path is directory",
+			args:          []string{"./"},
+			expectedError: true,
+		},
+		{
+			name:          "invalid: manifest path does not exist",
+			args:          []string{notExistFilePath},
+			expectedError: true,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			if err := validateManifestsPath(tc.args...); (err != nil) != tc.expectedError {
+				t.Fatalf("expected error: %v, saw: %v, error: %v", tc.expectedError, (err != nil), err)
+			}
+		})
+	}
+
+}