Index migration

cmd/krew/cmd/root.go

@@ -31,6 +31,7 @@ import (
 	"sigs.k8s.io/krew/cmd/krew/cmd/internal"
 	"sigs.k8s.io/krew/internal/environment"
 	"sigs.k8s.io/krew/internal/gitutil"
+	"sigs.k8s.io/krew/internal/indexmigration"
 	"sigs.k8s.io/krew/internal/installation"
 	"sigs.k8s.io/krew/internal/installation/receipt"
 	"sigs.k8s.io/krew/internal/installation/semver"
@@ -138,6 +139,17 @@ func preRun(cmd *cobra.Command, _ []string) error {
 		return errors.New("krew home outdated")
 	}
 
+	if _, ok := os.LookupEnv("X_KREW_ENABLE_MULTI_INDEX"); ok {
+		isMigrated, err = indexmigration.Done(paths)
+		if err != nil {
+			return errors.Wrap(err, "error getting file info")
+		}
+		if !isMigrated && cmd.Use != "index-upgrade" {
+			fmt.Fprintln(os.Stderr, "You need to perform a migration to continue using krew.\nPlease run `kubectl krew system index-upgrade`")
+			return errors.New("krew index outdated")
+		}
+	}
+
 	if installation.IsWindows() {
 		klog.V(4).Infof("detected windows, will check for old krew installations to clean up")
 		err := cleanupStaleKrewInstallations()

cmd/krew/cmd/system.go

@@ -15,8 +15,11 @@
 package cmd
 
 import (
+	"os"
+
 	"github.com/spf13/cobra"
 
+	"sigs.k8s.io/krew/internal/indexmigration"
 	"sigs.k8s.io/krew/internal/receiptsmigration"
 )
 
@@ -50,7 +53,24 @@ This command will be removed without further notice from future versions of krew
 	PreRunE: ensureIndexUpdated,
 }
 
+var indexUpgradeCmd = &cobra.Command{
+	Use:   "index-upgrade",
+	Short: "Perform a migration of the krew index",
+	Long: `Krew became more awesome! To use the new features, you need to run this
+one-time migration, which will enable installing plugins from custom indexes.
+
+This command will be removed without further notice from future versions of krew.
+`,
+	Args: cobra.NoArgs,
+	RunE: func(cmd *cobra.Command, args []string) error {
+		return indexmigration.Migrate(paths)
+	},
+}
+
 func init() {
+	if _, ok := os.LookupEnv("X_KREW_ENABLE_MULTI_INDEX"); ok {
+		systemCmd.AddCommand(indexUpgradeCmd)
+	}
 	systemCmd.AddCommand(receiptsUpgradeCmd)
 	rootCmd.AddCommand(systemCmd)
 }

internal/indexmigration/migration.go

@@ -0,0 +1,62 @@
+// Copyright 2019 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 indexmigration
+
+import (
+	"os"
+	"path/filepath"
+
+	"github.com/pkg/errors"
+	"k8s.io/klog"
+
+	"sigs.k8s.io/krew/internal/environment"
+	"sigs.k8s.io/krew/internal/gitutil"
+	"sigs.k8s.io/krew/pkg/constants"
+)
+
+// Done checks if the krew installation requires a migration to support multiple indexes.
+// A migration is necessary when the index directory contains a ".git" directory.
+func Done(paths environment.Paths) (bool, error) {
+	_, err := os.Stat(filepath.Join(paths.IndexPath(), ".git"))
+	if err == nil {
+		return false, nil
+	} else if os.IsNotExist(err) {
+		return true, nil
+	}
+	return false, err
+}
+
+// Migrate removes the index directory and then clones krew-index to the new default index path.
+func Migrate(paths environment.Paths) error {
+	isMigrated, err := Done(paths)
+	if err != nil {
+		return errors.Wrap(err, "failed to check if index migration is complete")
+	}
+	if isMigrated {
+		klog.V(2).Infoln("Already migrated")
+		return nil
+	}
+
+	err = os.RemoveAll(paths.IndexPath())
+	if err != nil {
+		return errors.Wrapf(err, "could not remove index directory %q", paths.IndexPath())
+	}
+	err = gitutil.EnsureCloned(constants.IndexURI, filepath.Join(paths.IndexPath(), "default"))
+	if err != nil {
+		return errors.Wrap(err, "failed to clone index")
+	}
+	klog.Infof("Migration completed successfully.")
+	return nil
+}

internal/indexmigration/migration_test.go

@@ -0,0 +1,67 @@
+// Copyright 2019 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 indexmigration
+
+import (
+	"os"
+	"testing"
+
+	"sigs.k8s.io/krew/internal/environment"
+	"sigs.k8s.io/krew/internal/testutil"
+)
+
+func TestIsMigrated(t *testing.T) {
+	if _, ok := os.LookupEnv("X_KREW_ENABLE_MULTI_INDEX"); !ok {
+		t.Skip("Set X_KREW_ENABLE_MULTI_INDEX variable to run this test")
+	}
+
+	tests := []struct {
+		name     string
+		dirPath  string
+		expected bool
+	}{
+		{
+			name:     "Already migrated",
+			dirPath:  "index/default/.git",
+			expected: true,
+		},
+		{
+			name:     "Not migrated",
+			dirPath:  "index/.git",
+			expected: false,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			tmpDir, cleanup := testutil.NewTempDir(t)
+			defer cleanup()
+
+			err := os.MkdirAll(tmpDir.Path(test.dirPath), os.ModePerm)
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			newPaths := environment.NewPaths(tmpDir.Root())
+			actual, err := Done(newPaths)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if actual != test.expected {
+				t.Errorf("Expected %v but found %v", test.expected, actual)
+			}
+		})
+	}
+}