README.md

cobra-extensions

cobra-extensions is an extension package for the well-known Cobra library, designed to enhance command management by introducing a declarative approach for binding flags to command structs. With this approach, you build complex CLI applications consisting of many commands in a clean and organized manner.

By leveraging command structs, adopting patterns like dependency injection becomes far easier, further simplifying the design of scalable and maintainable CLI tools. The library automates flag setup using struct tags, reducing boilerplate and improving developer productivity.

Usage

Using the Cobra extensions is a no-brainer. Use, go get to install the latest version of the library.

$ go get -u github.com/matzefriedrich/cobra-extensions@latest

Next, include Cobra extensions in your application.

import (
	"github.com/matzefriedrich/cobra-extensions/pkg/commands"
	"github.com/matzefriedrich/cobra-extensions/pkg/types"
	"github.com/spf13/cobra"
)

Example

All it needs is the definition of a struct that implements the TypedCommand interface. Public fields are annotated with flag tags to define flags and bind them to the struct once parsed. A private field of type CommandName specifies the command's name. For instance:

package commands

import (
	"fmt"
	"github.com/matzefriedrich/cobra-extensions/pkg/commands"
	"github.com/matzefriedrich/cobra-extensions/pkg/types"
	"github.com/spf13/cobra"
)

type helloCommand struct {
	use       types.CommandName `flag:"hello"`
	Arguments helloArgs
}

var _ types.TypedCommand = (*helloCommand)(nil)

type helloArgs struct {
	types.CommandArgs
	Name string
}

func CreateHelloCommand() *cobra.Command {
	instance := &helloCommand{
		Arguments: helloArgs{
			CommandArgs: types.NewCommandArgs(types.MinimumArgumentsRequired(1)),
		}}
	return commands.CreateTypedCommand(instance)
}

func (c *helloCommand) Execute() {
	fmt.Printf("Hello %s.\n", c.Arguments.Name)
}

A CreateHelloCommand factory method creates a new helloCommand instance and utilizes the CreateTypedCommand method to create and initialize a Cobra command.

package main

import (
	"github.com/matzefriedrich/cobra-extensions/example/commands"
	"github.com/matzefriedrich/cobra-extensions/pkg/charmer"
	"github.com/spf13/cobra"
)

func main() {

	app := charmer.NewRootCommand("simple-example", "")

	app.AddCommand(commands.CreateHelloCommand())

	err := app.Execute()
	if err != nil {
		panic(err)
	}
}