Golang Cobra详解（二）

代码目录：

 

main.go

package main

import "cobraDemo/cmd"

func main() {
	cmd.Execute()
}

root.go

package cmd

import (
	"fmt"
	"github.com/spf13/cobra"
	"os"

	"github.com/spf13/viper"
)

var cfgFile string
//增加name参数
var name string

var rootCmd = &cobra.Command{
	Use:   "demo",
	Short: "A brief description of your application",
	Long: `A longer description that spans multiple lines and likely contains
examples and usage of using your application. For example:

Cobra is a CLI library for Go that empowers applications.
This application is a tool to generate the needed files
to quickly create a Cobra application.`,
	Run: func(cmd *cobra.Command, args []string) {
		//赋值
		fmt.Println(name)
	},
}

func Execute() {
	cobra.CheckErr(rootCmd.Execute())
}

func init() {
	cobra.OnInitialize(initConfig)
	rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.demo.yaml)")
	rootCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
	//参数给变量赋值
	rootCmd.Flags().StringVar(&name, "name", "", "name demo")
}

func initConfig() {
	if cfgFile != "" {
		viper.SetConfigFile(cfgFile)
	} else {
		home, err := os.UserHomeDir()
		cobra.CheckErr(err)
		viper.AddConfigPath(home)
		viper.SetConfigType("yaml")
		viper.SetConfigName(".demo")
	}

	viper.AutomaticEnv()
	if err := viper.ReadInConfig(); err == nil {
		fmt.Fprintln(os.Stderr, "Using config file:", viper.ConfigFileUsed())
	}
}

test.go

/*
Copyright © 2021 NAME HERE 

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 cmd

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

// testCmd represents the test command
var testCmd = &cobra.Command{
	Use:   "test",
	Short: "A brief description of your command",
	Long: `A longer description that spans multiple lines and likely contains examples
and usage of using your command. For example:

Cobra is a CLI library for Go that empowers applications.
This application is a tool to generate the needed files
to quickly create a Cobra application.`,
	Run: func(cmd *cobra.Command, args []string) {
		fmt.Println("test called")
	},
}

func init() {
	rootCmd.AddCommand(testCmd)
}

带着问题看代码

1.root.go定义的rootCmd是如何执行到Run的呢？

2.test.go 添加的rootCmd.AddCommand(testCmd)是如何添加到rootCmd当中解析的呢？