Kubectl Plugin Builder

$ mkdir kubectl-demo && cd kubectl-demo
$ kubectl-plugin-builder new github.com/Drumato/kubectl-demo
Initialization Complete!
Run `go mod tidy` to install third-party modules.

$ go mod tidy
$ make > /dev/null
$ ./kubectl-demo -h
Usage:
  demo [flags]

Flags:
  -h, --help            help for demo
  -o, --output string   the command's output mode (default "normal")

// Code generated by kubectl-plugin-builder.
package main

import (
        "fmt"
        "github.com/Drumato/kubectl-demo/internal/cmd/demo"
        "os"

        "k8s.io/cli-runtime/pkg/genericclioptions"
)

func main() {
        streams := genericclioptions.IOStreams{
                In:     os.Stdin,
                Out:    os.Stdout,
                ErrOut: os.Stderr,
        }

        if err := demo.NewCommand(&streams).Execute(); err != nil {
                fmt.Fprintf(os.Stderr, "ERROR: %+v\n", err)
                os.Exit(1)
        }
}

// Code generated by kubectl-plugin-builder.

/* MIT License
 *
 * Copyright (c) 2021 you
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package cmd

import (
        "github.com/spf13/cobra"
)

type CLINodeOptions interface {
        Complete(cmd *cobra.Command, args []string) error
        Validate() error
        Run() error
}

type OutputMode = string

const (
        OutputModeNormal OutputMode = "normal"
        // OutputModeJSON
        // OutputModeYAML
)

$ cat internal/cmd/demo/command.go
// Code generated by kubectl-plugin-builder; DO NOT EDIT.

/* MIT License
 *
 * Copyright (c) 2021 you
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package demo

import (
        "github.com/spf13/cobra"

        "github.com/Drumato/kubectl-demo/internal/cmd"
        "k8s.io/cli-runtime/pkg/genericclioptions"
)

var (
        // demoOutputModeFlag provides
        // user-passed option to options.
        demoOutputModeFlag string
)

// WARNING: don't rename this function.
func NewCommand(streams *genericclioptions.IOStreams) *cobra.Command {
        c := &cobra.Command{
                Use: "demo",

                Aliases: []string{},

                RunE: func(cmd *cobra.Command, args []string) error {
                        o := &options{streams: streams}
                        if err := o.Complete(cmd, args); err != nil {
                                return err
                        }

                        if err := o.Validate(); err != nil {
                                return err
                        }

                        return o.Run()
                },
        }

        hangChildrenOnCommand(c, streams)
        defineCommandFlags(c)

        return c
}

// hangChildrenOnCommand enumerates command's children and attach them into it.
func hangChildrenOnCommand(c *cobra.Command, streams *genericclioptions.IOStreams) {
}

// defineCommandFlags declares primitive flags.
func defineCommandFlags(c *cobra.Command) {
        c.Flags().StringVarP(
                &demoOutputModeFlag,
                "output",
                "o",
                cmd.OutputModeNormal,
                "the command's output mode",
        )
}

license: MIT
packageName: github.com/Drumato/kubectl-demo
root:
  name: demo
  year: 2021
  author: you
  defPath: internal/cmd/demo
  children:

// Code generated by kubectl-plugin-builder.

/* MIT License
 *
 * Copyright (c) 2021 you
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package demo

import (
        "fmt"

        "github.com/Drumato/kubectl-demo/internal/cmd"
        "github.com/spf13/cobra"
        "k8s.io/cli-runtime/pkg/genericclioptions"
)

// this assignment ensures
// options struct must implement CLINodeOptions interface.
var _ cmd.CLINodeOptions = &options{}

type options struct {
        cmd        *cobra.Command
        args       []string
        streams    *genericclioptions.IOStreams
        outputMode cmd.OutputMode
}

// Complete implements CLINodeOptions interface.
func (o *options) Complete(cmd *cobra.Command, args []string) error {
        o.cmd = cmd
        o.args = args
        o.outputMode = demoOutputModeFlag
        return nil
}

// Validate implements CLINodeOptions interface.
func (o *options) Validate() error {
        return nil
}

// Run implements CLINodeOptions interface.
func (o *options) Run() error {
        switch o.outputMode {
        // case cmd.OutputModeJSON:
        // case cmd.OutputModeYAML:
        case cmd.OutputModeNormal:
                _, err := fmt.Fprintf(o.streams.Out, "%s\n", o.cmd.Use)
                return err
        }

        return fmt.Errorf("unsupported output format '%s' found", o.outputMode)
}

license: MIT
packageName: github.com/Drumato/kubectl-demo
root:
  name: demo
  year: 2021
  author: you
  defPath: internal/cmd/demo
  flags:
  - name: flag1 # added
    type: string
    description: controls root command behavior
  - name: flag2 # added
    type: string
    description: controls root command behavior
  children:
  - name: subcmd1
    year: 2021
    author: you
    defPath: internal/cmd/demo/subcmd1
  - name: subcmd2
    year: 2021
    author: you
    defPath: internal/cmd/demo/subcmd2

$ make > /dev/null
$ ./kubectl-demo -h
Usage:
  demo [flags]
  demo [command]

Available Commands:
  completion  generate the autocompletion script for the specified shell
  help        Help about any command
  subcmd1
  subcmd2

Flags:
      --flag1 string    controls root command behavior
      --flag2 string    controls root command behavior
  -h, --help            help for demo
  -o, --output string   the command's output mode (default "normal")

Use "demo [command] --help" for more information about a command.