Climate

Climate "CLI Mate" aims to make creating CLIs in Go easy (and fun!), similar to python-fire.
It's also built on top of Cobra and so comes with "batteries included" (help, shell completion etc.).

Usage

climate/cmd/examples/greet/main.go

Lines 11 to 54 in 45ac608

	// Exported struct fields are automatically declared as flags --
	// 1. Field names are converted to kebab-case and are used as flag names.
	// That said, users can pass flags in camelCase, PascalCase, snake_case or
	// SCREAMING_SNAKE_CASE and everything just works (thanks to normalization).
	// 2. Field types are used as flag types (string, bool, int, etc.).
	// 3. "short" subfield tags (under the "cli" tags) are used as short flag names
	// (as is). It's also possible to omit the value, in which case the first
	// letter of the field name is used.
	// 4. "default" field tags are used as default values (of course, with
	// automatic type conversion from raw string to the actual field type).
	// 5. Field docs / comments are used* as flag usage strings (as is).
	// 6. "required" subfield tags (under the "cli" tags) are used to mark the
	// flags as required (i.e., the command is errored out without these flags).
	type greetOptions struct {
	Greeting string `cli:"short" default:"Hello"` // greeting to use
	Name string `cli:"short=n" default:"World"` // name to greet
	Times int `cli:"short,required"` // number of times to greet
	}
	// Func is automatically converted to a command --
	// 1. Param names are converted to kebab-case and used* as part of the usage
	// string ("command [opts] [args]", for example).
	// 2. (Optional) First argument if a struct pointer, is used to declare flags.
	// 3. (Optional) Next argument if a string slice is used to collect args.
	// 4. Doc is used* as long help string (as is).
	// 5. Usage directive is used* to explicitly set the usage string.
	// Greet someone.
	func greet(opts *greetOptions) {
	for i := 0; i < opts.Times; i++ {
	fmt.Printf("%v, %v!\n", opts.Greeting, opts.Name)
	}
	}
	// * These only work if you generate and pass along "metadata" like below --
	//go:generate go run github.com/avamsi/climate/cmd/cligen --out=md.cli
	//go:embed md.cli
	var md []byte
	func main() {
	climate.RunAndExit(climate.Func(greet), climate.WithMetadata(md))
	}

$ greet --help

Greet someone.

Usage:
  greet [opts]

Flags:
  -g, --greeting string (default Hello)  greeting to use
  -n, --name     string (default World)  name to greet
  -t, --times    int                     number of times to greet
  -h, --help                             help for greet
  -v, --version                          version for greet

Subcommands

climate/cmd/examples/jj/main.go

Lines 14 to 87 in 45ac608

	// See ../greet/main.go first for some details that are not covered here.
	// Struct is automatically converted to a command --
	// 1. Struct names are converted to lowercase and used as the command name.
	// 2. Struct fields are automatically declared as "global" flags.
	// 3. Struct methods are automatically converted to subcommands --
	// 1. Method names are converted to lowercase and used as the command name.
	// 2. Method docs are truncated and are used* as short help strings.
	// 3. Method directives are used* to declare aliases or explicitly set the
	// short help strings (//cli:aliases, for example).
	// 4. "Sub-structs" are automatically converted to subcommands, recursively.
	// Jujutsu (an experimental VCS).
	type jj struct {
	Repository string `cli:"short=R"` // `path` to the repo to operate on
	IgnoreWorkingCopy bool // don't snapshot / update the working copy
	}
	// Create a new repo in the given directory.
	func (j *jj) Init(ctx context.Context, dir *string) {
	fmt.Println("init", ctx, j, dir)
	}
	type squashOptions struct {
	Revision string `cli:"short" default:"@"`
	Interactive bool `cli:"short"` // interactively choose which parts to squash
	}
	// Move changes from a revision into its parent.
	//
	// After moving the changes into the parent, the child revision will have the
	// same content state as before. If that means that the change is now empty
	// compared to its parent, it will be abandoned. Without `--interactive`, the
	// child change will always be empty.
	//
	//cli:aliases am, amend
	func (j *jj) Squash(opts *squashOptions, paths [5]string) {
	fmt.Println("squash", j, opts, paths)
	}
	// Commands for working with the underlying Git repo.
	type git struct {
	J *jj
	}
	// Manage Git remotes.
	func (g *git) Remote() error {
	return errors.New("not implemented")
	}
	// Update the underlying Git repo with changes made in the repo.
	func (g *git) Export() {
	fmt.Println("export", g.J)
	}
	//go:generate go run github.com/avamsi/climate/cmd/cligen --out=md.cli
	//go:embed md.cli
	var md []byte
	func main() {
	// Note the recursive struct embedding below, which lets us create "deep"
	// subcommands like this (indentation implies subcommand) --
	//
	// jj
	// init
	// squash
	// git
	// remote
	// export
	// util
	// completion
	p := climate.Struct[jj](climate.Struct[git](), climate.Struct[util.Util]())
	climate.RunAndExit(p, climate.WithMetadata(md))
	}

$ jj --help

Jujutsu (an experimental VCS).

Usage:
  jj [command]

Available Commands:
  completion  Generate the autocompletion script for the specified shell
  git         Commands for working with the underlying Git repo
  help        Help about any command
  init        Create a new repo in the given directory
  squash      Move changes from a revision into its parent
  util        Infrequently used commands such as for generating shell completions
  version     Display jj's version information

Flags:
  -R, --repository          path  path to the repo to operate on
      --ignore-working-copy       don't snapshot / update the working copy
  -h, --help                      help for jj
  -v, --version                   version for jj

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

$ jj git --help

Commands for working with the underlying Git repo.

Usage:
  jj git [command]

Available Commands:
  export      Update the underlying Git repo with changes made in the repo
  remote      Manage Git remotes

Flags:
  -h, --help  help for git

Global Flags:
      --ignore-working-copy       don't snapshot / update the working copy
  -R, --repository          path  path to the repo to operate on

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