completion.go

// Copyright 2018 The Kubeflow 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 (
	"fmt"
	"io"
	"log"
	"os"

	"github.com/spf13/cobra"
)

func NewCompletionCommand() *cobra.Command {
	var command = &cobra.Command{
		Use:   "completion SHELL",
		Short: "output shell completion code for the specified shell (bash or zsh)",
		Long: `Write bash or zsh shell completion code to standard output.

For bash, ensure you have bash completions installed and enabled.
To access completions in your current shell, run
$ source <(arena completion bash)
Alternatively, write it to a file and source in .bash_profile

For zsh, output to a file in a directory referenced by the $fpath shell
variable.
`,
		Run: func(cmd *cobra.Command, args []string) {
			if len(args) != 1 {
				cmd.HelpFunc()(cmd, args)
				os.Exit(1)
			}
			shell := args[0]
			rootCommand := NewCommand()
			rootCommand.BashCompletionFunction = bashCompletionFunc

			availableCompletions := map[string]func(io.Writer) error{
				"bash": rootCommand.GenBashCompletion,
				"zsh":  rootCommand.GenZshCompletion,
			}
			completion, ok := availableCompletions[shell]
			if !ok {
				fmt.Printf("Invalid shell '%s'. The supported shells are bash and zsh.\n", shell)
				os.Exit(1)
			}
			if err := completion(os.Stdout); err != nil {
				log.Fatal(err)
			}
		},
	}

	return command
}