gem-hunterCli-X is a command line library for Go, inspired by
spf13/cobra.
struct based API: Similar to cobra, go-clix/cli features a struct based
API for easy composition and discovery of available options.cli.Command can be nested for a git
like experience.spf13/pflag.<TAB> completion is supported for bash, zsh and
fish. But you can generate suggestions using Go code!Add the library to your project:
$ go get github.com/go-clix/cli
Then set up your root command:
package main import ( "fmt" "github.com/go-clix/cli" ) func main() { // create the root command rootCmd := cli.Command{ Use: "greet", Short: "print a message", Run: func(cmd *cli.Command, args []string) error { fmt.Println("Hello from Cli-X!") }, } // run and check for errors if err := rootCmd.Execute(); err != nil { fmt.Println(err) os.Exit(1) } }
Every command may have children:
// use a func to return a Command instead of // a global variable and `init()` func applyCmd() *cli.Command { cmd := &cli.Command{ Use: "apply", Short: "apply the changes" } cmd.Run = func(cmd *cli.Command, args []string) error { fmt.Println("applied", args[0]) } return cmd } func main() { rootCmd := &cli.Comand{ Use: "kubectl", Short: "Kubernetes management tool", } // add the child command rootCmd.AddChildren( applyCmd(), ) // run and check for errors if err := rootCmd.Execute(); err != nil { fmt.Println(err) os.Exit(1) } }
Note: Do not use the
init()function for setting up your commands. Create constructors as shown above!
A pflag.FlagSet can be accessed per command using *Command.Flags():
func applyCmd() *cli.Command { cmd := &cli.Command{ Use: "apply", Short: "apply the changes" } force := cmd.Flags().BoolP("force", "f", false, "skip checks") cmd.Run = func(cmd *cli.Command, args []string) error { fmt.Println("applied", args[0]) if *force { fmt.Println("The force was with us.") } } return cmd }
To make the apply subcommand also available as make and do:
func applyCmd() *cli.Command { cmd := &cli.Command{ Use: "apply", Aliases: []string{"make", "do"}, Short: "apply the changes" } }
Keep in mind that in --help outputs the command will still be called apply.
Cli-X has a very powerful cli completion system, based on
posener/complete.
It is powerful, because suggestions come directly from the Go application, not
from a bash script or similar.
Command and Flag names are automatically suggested, custom suggestions can be implemented for positional arguments and flag values:
Custom suggestions for flag values can be set up using Command.Predictors.
To do so, you need to add a complete.Predictor for that flag. Cli-X has a
number of predefined ones:
PredictAny(): Predicts available files and directories, like bash does when
having no better ideaPredictNone(): Predicts literally nothing. No suggestions will be shown.PredictSet(...string): Suggests from a predefined slice of optionsIf that's not sufficient, use PredictFunc(func(complete.Args) []string) to
create your own.
import ( "github.com/posener/complete" "github.com/go-clix/cli" ) func logsCmd() *cli.Command { cmd := &cli.Command{ Use: "logs", Short: "show logs of a pod", Predictors: map[string]complete.Predictor{ "output": cli.PredictSet("lines", "json", "logfmt"), }, } output := cmd.Flags().StringP("output", "o", "lines", "one of [lines, json, logfmt]") }
For positional arguments, Cli-X uses a slightly different interface, to allow
validation as well:
interface { Validate(args []string) error Predict(Args) []string }
Predefined options are also available:
ArgsAny(): accepts any number args, predicts files and directoriesArgsExact(n): accepts exactly n arguments. Predicts files and directories.ArgsRange(n, m): accepts between n and m arguments (inclusive). Predicts files and directories.ArgsNone(): accepts no args and predicts nothing.ArgsSet(...string): Accepts one argument, which MUST be included in the
given set. Predicts the values from the set.import ( "github.com/posener/complete" "github.com/go-clix/cli" ) func applyCmd() *cli.Command { cmd := &cli.Command{ Use: "logs", Short: "show logs of a pod", // we expect one argument which can be anything Args: cli.ArgsExact(1), } }