Cobra支持动态自定义flag

Tech

用GO实现了一个binary，这个binary会发送API请求去服务端，服务端完成对K8S环境的部署工作。
由于后端进行了大量封装，并且参数是非常多的，所以有了一个想法，具体的要求如下：

  1. 支持自定义flag列表
  2. help信息支持展示自定义的flag列表
  3. 列表信息来自于一个专门的API

基于这些需求，查询了很多文档后，并没有成功的例子，经过一下午的尝试，最后实现了预期的需求，分享一下。
回头准备写一篇post给cobra。

在Cobra的github repo里开了issue，询问是否有更加优雅和方便的方法，没想到Cobra的Collaborator竟然回复了，看起来现在的实现方法是一个正确的方向。
https://github.com/spf13/cobra/issues/1758

API部分， python flask实现的，简单定义了数据结构，然后返回一个json结果。

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@ns.route('/custom-api')
class CustomAPI(Resource):
    def get(self):
        flags_list = {
            "cert": {
                "type": "string",
                "des": "add self-signed certs for private registries. Format: registry-name1:/path/to/cert-file1,registry-name2:/path/to/cert-file2,...",
                "default": ""
            },
            "csf-grocery": {
                "type": "bool",
                "des": "set up CSF Grocery",
                "default": True
            }
        }
        return json_success(flags_list)
utils/customized_flags.go
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package utils

import (
	"fmt"
	"os"
	"strings"

	resty "github.com/go-resty/resty/v2"
	"github.com/spf13/cobra"
	"github.com/spf13/viper"
	"github.com/tidwall/gjson"
)

var customizedMap = make(map[string]interface{})

func ParseCutomizedFlags(url string, requiredFlags []string, cmd *cobra.Command, args []string) map[string]interface{} {

	if len(requiredFlags) > 0 && len(args) == 0 {
		cmd.Help()
		fmt.Println()
		os.Exit(0)
	}

	argsArrayString := strings.Join(args, "#")
	for _, flag := range requiredFlags {
		if !strings.Contains(argsArrayString, "--"+flag) {
			fmt.Printf("required flag(s) \"%v\" not set\n", flag)
			cmd.Help()
			fmt.Println()
			os.Exit(1)
		}
	}

	fullURL := viper.GetString("datacenter-server-api") + url
	var customizedData gjson.Result
	client := resty.New()
	resp, err := client.R().ForceContentType("application/json").EnableTrace().Get(fullURL)
	if err == nil {
		if gjson.Get(resp.String(), "status").String() == "OK" {
			customizedData = gjson.Get(resp.String(), "data")
		}
	} else {
		fmt.Println(err.Error())
		os.Exit(1)
	}

	if len(customizedData.Map()) > 0 {
		for key_name, valueMap := range customizedData.Map() {
			value_type := valueMap.Get("type").String()
			if value_type == "string" {
				cmd.Flags().String(string(key_name), valueMap.Map()["default"].String(), valueMap.Map()["des"].String())
			} else if value_type == "bool" {
				cmd.Flags().Bool(string(key_name), valueMap.Map()["default"].Bool(), valueMap.Map()["des"].String())
			}
		}
	}

	cmd.DisableFlagParsing = false
	err = cmd.ParseFlags(args)
	if err != nil {
		fmt.Println(err)
		cmd.Help()
		fmt.Println()
		os.Exit(1)
	}

	if cmd.Flag("help").Value.String() == "true" {
		cmd.Help()
		fmt.Println()
		os.Exit(0)
	}

	if len(customizedData.Array()) > 0 {
		for key_name := range customizedData.Map() {
			if cmd.Flag(key_name).Value.String() != cmd.Flag(key_name).DefValue {
				customizedMap[key_name] = cmd.Flag(key_name).Value
			}
		}
	}

	return customizedMap
}


调用：

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import (
	"fmt"

	"github.com/spf13/cobra"
	"nuke.csf.nokia.net/nuke-cli/utils"
)

var Region string
var requiredFlags []string

var DemoClusterCreate = &cobra.Command{
	Use:                "demo [string to print]",
	Short:              "demo anything to the screen",
	Long:               `demo is for printing anything back to the screen. For many years people have printed back to the screen.`,
	RunE:               createDemoCluster,
	DisableFlagParsing: true,
}

func createDemoCluster(cmd *cobra.Command, args []string) error {

	var customizedMap = utils.ParseCutomizedFlags("/api/v1/demo/custom-api", requiredFlags, cmd, args)

	for va := range customizedMap {
		fmt.Println(va)
		fmt.Println(customizedMap[va])
	}

	fmt.Println(Region)
	return nil
}

func init() {
	// DemoClusterCreate.Flags().StringVarP(&demoVersion, "version", "v", "1.14", "Venilla version, current can be set as 1.10 , 1.11 1.12")
	DemoClusterCreate.Flags().StringVarP(&Region, "region", "r", "zone-a", "(required) AWS region")
	// DemoClusterCreate.MarkFlagRequired("region")
	//特殊处理required的参数
	requiredFlags = append(requiredFlags, "region") 

}

最后执行的结果：

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skeetw@N-20HEPF12NB62 MINGW64 /d/CSF_NCM/CSF-NUKE-CLI (1.0)
$ go run nuke.go create cluster demo --cert xxxx --csf-grocery=false
required flag(s) "region" not set
demo is for printing anything back to the screen. For many years people have printed back to the screen.

Usage:
  nuke create cluster demo [string to print] [flags]

Flags:
  -h, --help            help for demo
  -r, --region string   (required) AWS region (default "zone-a")

Global Flags:
      --datacenter-server-api string   data center server api (default "http://127.0.0.1:5678")
      --log string                     nuke log level [debug, info] (default "info")
  -o, --output string                  result output format. [json, yaml, file] (default "json")
      --output-folder string           when output type if file, all result files will be save to this folder. (default "./output/")
      --wrap-processbar                if need to wrap process bar when running a long task (default true)

exit status 1

skeetw@N-20HEPF12NB62 MINGW64 /d/CSF_NCM/CSF-NUKE-CLI (1.0)
$ go run nuke.go create cluster demo --cert xxxx --csf-grocery=false --region=989
csf-grocery
false
cert
xxxx
989

skeetw@N-20HEPF12NB62 MINGW64 /d/CSF_NCM/CSF-NUKE-CLI (1.0)
$ go run nuke.go create cluster demo --cert xxxx --region=989
cert
xxxx
989

skeetw@N-20HEPF12NB62 MINGW64 /d/CSF_NCM/CSF-NUKE-CLI (1.0)
$ go run nuke.go create cluster demo --region=989
989

skeetw@N-20HEPF12NB62 MINGW64 /d/CSF_NCM/CSF-NUKE-CLI (1.0)
$ go run nuke.go create cluster demo
demo is for printing anything back to the screen. For many years people have printed back to the screen.

Usage:
  nuke create cluster demo [string to print] [flags]

Flags:
  -h, --help            help for demo
  -r, --region string   (required) AWS region (default "zone-a")

Global Flags:
      --datacenter-server-api string   data center server api (default "http://127.0.0.1:5678")
      --log string                     nuke log level [debug, info] (default "info")
  -o, --output string                  result output format. [json, yaml, file] (default "json")
      --output-folder string           when output type if file, all result files will be save to this folder. (default "./output/")
      --wrap-processbar                if need to wrap process bar when running a long task (default true)

Notice: 正常情况下，这里会有一个基于utteranc.es的留言系统，如果看不到，可能需要科学上网方式。