CLI App 代码布局 (App Layout)

app [commands] [flags] [arguments]

app cmd1 -a -b cmd2 cmd3 -c -d -e file1 file2 file3

-avraz == -a -v -ra -z
-raavz == -ra -a -v -z

# 由于 cmd1 有多个下级子命令，所以下一行命令导致帮助屏自动被显示
$ app cmd1
# 显式要求帮助屏
$ app cmd1 cmd2 -a -bc --help
# 或者借助环境变量
$ HELP=1 app cmd1 cmd2 -a -bc

your_cmdr_app versions
your_cmdr_app version
your_cmdr_app ver

app cmd1 cmd2 -v --help
HELP=1 app cmd1 cmd2 -v

 root.NewSubCommand("soundex", "snd", "sndx", "sound").
  Action(func(cmd *cmdr.Command, args []string) (err error) {
   for ix, s := range args {
    fmt.Printf("%5d. %s => %s\n", ix, s, cmdr.Soundex(s))
   }
   return
  })

var debugMode bool = cmdr.GetR("debug", false)
var stringVal string = cmdr.GetStringR("test.vals.string-val", "hello, world")
var intVal int = cmdr.GetIntR("test.vals.int-val", -1)
var uintVal uint = cmdr.GetUintR("test.vals.uint-val", 99)
var sslice []int64 = cmdr.GetIntSliceR("test.vals.int-slice-val", 5,6,7)

var m map[string]interface{} = cmdr.GetMapR("test.vals")
var i interface{} = cmdr.Get("test.vals")
 
type ServerConfig struct {
  Port int
  HttpMode int
  EnableTLS bool
}
var serverConfig = new(ServerConfig)
cmdr.GetSectionFrom("server", &serverConfig)
assert serverConfig.Port == 7100

package main
 
import (
 "fmt"
 "github.com/hedzr/cmdr"
 cmdr_examples "github.com/hedzr/cmdr-examples"
 "gopkg.in/hedzr/errors.v2"
)
 
func main() {
 Entry()
}
 
func Entry() {
 if err := cmdr.Exec(buildRootCmd(), 
      cmdr.WithUnhandledErrorHandler(onUnhandledErrorHandler),
                      // ... more WithXXX(),
  ); err != nil {
  fmt.Printf("error: %+v\n", err)
 }
}
 
func onUnhandledErrorHandler(err interface{}) {
 if cmdr.GetBoolR("enable-ueh") {
  dumpStacks()
  return
 }
 
 panic(err)
}
 
func dumpStacks() {
 fmt.Printf("=== BEGIN goroutine stack dump ===\n%s\n=== END goroutine stack dump ===\n", errors.DumpStacksAsString(true))
}
 
func buildRootCmd() (rootCmd *cmdr.RootCommand) {
 root := cmdr.Root(appName, cmdr_examples.Version).
  Copyright(copyright, "hedzr").
  Description(desc, longDesc).
  Examples(examples)
 rootCmd = root.RootCommand()
 
 cmdr.NewBool(false).
  Titles("enable-ueh", "ueh").
  EnvKeys("ENABLE_UEH").
  Description("Enables the unhandled exception handler?").
  AttachTo(root)
 
 soundex(root)
 panicTest(root)
 
 return
}
 
func soundex(root cmdr.OptCmd) {
 // soundex
 
 root.NewSubCommand("soundex", "snd", "sndx", "sound").
  Description("soundex test").
  Group("Test").
  TailPlaceholder("[text1, text2, ...]").
  Action(func(cmd *cmdr.Command, args []string) (err error) {
   for ix, s := range args {
    fmt.Printf("%5d. %s => %s\n", ix, s, cmdr.Soundex(s))
   }
   return
  })
}
 
func panicTest(root cmdr.OptCmd) {
 // panic test
 
 pa := root.NewSubCommand("panic-test", "pa").
  Description("test panic inside cmdr actions", "").
  Group("Test")
 
 val := 9
 zeroVal := zero
 
 pa.NewSubCommand("division-by-zero", "dz").
  Description("").
  Group("Test").
  Action(func(cmd *cmdr.Command, args []string) (err error) {
   fmt.Println(val / zeroVal)
   return
  })
 
 pa.NewSubCommand("panic", "pa").
  Description("").
  Group("Test").
  Action(raisePanic)
}
 
func raisePanic(cmd *cmdr.Command, args []string) (err error) {
  panic(9)
  return
}
 
const (
 appName   = "simple"
 copyright = "simple is an effective devops tool"
 desc      = "simple is an effective devops tool. It make an demo application for `cmdr`."
 longDesc  = "simple is an effective devops tool. It make an demo application for `cmdr`."
 examples  = `
$ {{.AppName}} gen shell [--bash|--zsh|--auto]
  generate bash/shell completion scripts
$ {{.AppName}} gen man
  generate linux man page 1
$ {{.AppName}} --help
  show help screen.
`
 overview = ``
 
 zero = 0
)

  ep            Exclude paths from names
  ep1           Exclude base directory from names
  ep3           Expand paths to full including the drive letter

$ docker checkpoint create --help
 
Usage:    docker checkpoint create [OPTIONS] CONTAINER CHECKPOINT
 
Create a checkpoint from a running container
 
Options:
      --checkpoint-dir string   Use a custom checkpoint storage directory
      --leave-running           Leave the container running after checkpoint

func WithPagerEnabled() ExecOption

func main(){
  if err := cmdr.Exec(buildRootCmd(), WithNoCommandAction(true)); err != nil {
    log.Fatal(err)
  }
  
  // ...
  if cmdr.GetBoolR("opt1")  {
    //...
  }
  if filename := cmdr.GetStringR("filename1"); filename != "" {
    //...
  }
}