Adds kustomize edit add base command

This pull request adds support for editing the kustomization.yaml in the current directory with a base.

pkg/commands/addbase.go

@@ -0,0 +1,95 @@
+/*
+Copyright 2017 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 commands
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/spf13/cobra"
+
+	"github.com/kubernetes-sigs/kustomize/pkg/constants"
+	"github.com/kubernetes-sigs/kustomize/pkg/fs"
+)
+
+type addBaseOptions struct {
+	baseDirectoryPath string
+}
+
+// newCmdAddBase adds the file path of the kustomize base to the kustomization file.
+func newCmdAddBase(fsys fs.FileSystem) *cobra.Command {
+	var o addBaseOptions
+
+	cmd := &cobra.Command{
+		Use:   "base",
+		Short: "Adds a directory path to a base kustomization to the current directory's kustomization file.",
+		Example: `
+		add base {filepath}`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			err := o.Validate(args)
+			if err != nil {
+				return err
+			}
+			err = o.Complete(cmd, args)
+			if err != nil {
+				return err
+			}
+			return o.RunAddBase(fsys)
+		},
+	}
+	return cmd
+}
+
+// Validate validates addBase command.
+func (o *addBaseOptions) Validate(args []string) error {
+	if len(args) != 1 {
+		return errors.New("must specify a base directory")
+	}
+	o.baseDirectoryPath = args[0]
+	return nil
+}
+
+// Complete completes addBase command.
+func (o *addBaseOptions) Complete(cmd *cobra.Command, args []string) error {
+	return nil
+}
+
+// RunAddBase runs addBase command (do real work).
+func (o *addBaseOptions) RunAddBase(fsys fs.FileSystem) error {
+	_, err := fsys.Stat(o.baseDirectoryPath)
+	if err != nil {
+		return err
+	}
+
+	mf, err := newKustomizationFile(constants.KustomizationFileName, fsys)
+	if err != nil {
+		return err
+	}
+
+	m, err := mf.read()
+	if err != nil {
+		return err
+	}
+
+	if stringInSlice(o.baseDirectoryPath, m.Bases) {
+		return fmt.Errorf("base %s already in kustomization file", o.baseDirectoryPath)
+	}
+
+	m.Bases = append(m.Bases, o.baseDirectoryPath)
+
+	return mf.write(m)
+}