warren/main.go

package main

import (
	"flag"
	"fmt"
	"os"
	"strings"
	"text/template"
)

var BuildGitHash string
var BuildGitBranch string
var BuildDate string

var usagePrefix = `
warren is a tool for building, deploying and running multiple versions of a Go server

Usage: 
	warren command [args]
`

var usageTmpl = template.Must(template.New("usage").Parse(`
Commands:{{range .}}
     {{.Name | printf "%-10s"}} {{.Summary}}{{end}}
`))

var commands = []*Command{
	buildCmd,
	deployCmd,
}

func usage() {
	fmt.Println(BuildGitBranch, " ", BuildGitHash, " ", BuildDate)
	fmt.Print(usagePrefix)
	usageTmpl.Execute(os.Stdout, commands)
}

func main() {

	flag.Usage = usage
	flag.Parse()

	args := flag.Args()
	if len(args) == 0 || args[0] == "-h" {
		flag.Usage()
		return
	}

	var cmd *Command
	name := args[0]
	for _, c := range commands {
		if strings.HasPrefix(c.Name, name) {
			cmd = c
			break
		}
	}

	if cmd == nil {
		fmt.Printf("error: unknown command %q\n", name)
		flag.Usage()
		os.Exit(1)
	}

	cmd.Exec(args[1:])

}