cli.go

// Package cli provides a minimal framework for creating and organizing command line
// Go applications. cli is designed to be easy to understand and write, the most simple
// cli application can be written as follows:
//
//	func main() {
//		(&cli.Command{}).Run(context.Background(), os.Args)
//	}
//
// Of course this application does not do much, so let's make this an actual application:
//
//	func main() {
//		cmd := &cli.Command{
//	  		Name: "greet",
//	  		Usage: "say a greeting",
//	  		Action: func(c *cli.Context) error {
//	  			fmt.Println("Greetings")
//	  			return nil
//	  		},
//		}
//
//		cmd.Run(context.Background(), os.Args)
//	}
package cli

import (
	"fmt"
	"os"
	"runtime"
	"strings"
)

var isTracingOn = os.Getenv("URFAVE_CLI_TRACING") == "on"

func tracef(format string, a ...any) {
	if !isTracingOn {
		return
	}

	if !strings.HasSuffix(format, "\n") {
		format = format + "\n"
	}

	pc, file, line, _ := runtime.Caller(1)
	cf := runtime.FuncForPC(pc)

	fmt.Fprintf(
		os.Stderr,
		strings.Join([]string{
			"## URFAVE CLI TRACE ",
			file,
			":",
			fmt.Sprintf("%v", line),
			" ",
			fmt.Sprintf("(%s)", cf.Name()),
			" ",
			format,
		}, ""),
		a...,
	)
}