As I continue my journey in learning more about golang. I am venturing off to find frameworks that I can use to write better clis or apis. There is a popular framework called Cobra that helps golang developers generate cli applications that can scale. kubectl, hugo, and gh are few of many that are leveraging Cobra.

I do have a cookiecutter template that I can use to generate an inital cobra application. We will use the cookie template to generate depot cli application to handle different types of storage like aws, fs, gcloud, and azure.

We won’t be implementing CRUD operations for each storage type. We will mock out functionality using print statements to demonstrate Cobra’s subcommand capabilities.

Steps Link to heading

  1. My Cookiecutter blog post can help with setting up the inital cobra application

  2. Once you have setup the cli application you can run these commands to generate subcommands e.g. go run main.go aws

    cobra-cli add aws
cobra-cli add fs
cobra-cli add azure
cobra-cli add gcloud

    Output if you run go run main.go -h

    ➜  depot git:(main) ✗ go run main.go -h
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.

Usage:
depot [command]

Available Commands:
aws         A brief description of your command
azure       A brief description of your command
completion  Generate the autocompletion script for the specified shell
fs          A brief description of your command
gcloud      A brief description of your command
help        Help about any command

Flags:
-h, --help     help for depot
-t, --toggle   Help message for toggle

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

  3. Add these commands into crud.go and make sure to register them e.g.

    func init() {
    rootCmd.AddCommand(awsCmd)
    awsCmd.AddCommand(CpCmd)
    awsCmd.AddCommand(DeleteCmd)
    awsCmd.AddCommand(ListCmd)
}

    Here is the output if you run go run main.go aws -h. You should see cp, ls, delete subcommands

    ➜  depot git:(main) ✗ go run main.go aws -h
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.

Usage:
depot aws [flags]
depot aws [command]

Available Commands:
cp          A brief description of your command
delete      A brief description of your command
ls          A brief description of your command

Flags:
-h, --help   help for aws

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

  4. Execute sub-sub commands to verify functionality.

    ➜  depot git:(main) go run main.go aws ls
cp called
➜  depot git:(main) ✗ go run main.go aws ls
ls called
➜  depot git:(main) ✗ go run main.go aws delete
delete called

Congrulations, you now have a cobra cli application with various subcommands where you can extend functionality if you would like

Learnings Link to heading

With Cobra, I feel it follows a Makefile approach where you can organized your tooling in way that makes logical sense to the user

APPNAME VERB NOUN --ADJECTIVE

In combination with the golang programming language where you can generate executables based on the hardware and os, this cli framework lend itself to generate powerful cli tools.

Resources Link to heading