♻️ change stream by args

cmd/leetgode/main.go

@@ -4,6 +4,7 @@ import (
  "context"
  "flag"
  "fmt"
+ "io"
  "io/ioutil"
  "log"
  "os"
@@ -12,35 +13,51 @@ import (
 )
 
 func main() {
- flag.Usage = func() {
- if err := leetgode.ShowUsage(os.Stdout); err != nil {
- panic(err)
+ os.Exit(run(os.Stdout, os.Stderr, os.Args))
+}
+
+func run(stdout, stderr io.Writer, args []string) int {
+ if len(args) < 2 {
+ cmd := &leetgode.HelpCmd{}
+ if err := cmd.Run(context.Background(), []string{}); err != nil {
+ fmt.Fprintf(stderr, "help comamnd is faield: %v", err)
  }
+ return 1
  }
- flag.Parse()
- sub := flag.Arg(0)
- if len(sub) == 0 {
- cmd := &leetgode.HelpCmd{}
- if err := cmd.Run(context.Background(), []string{}); err !=nil{
- fmt.Printf("help comamnd is faield: %v", err)
+ sub := args[1]
+ f := flag.NewFlagSet(sub, flag.ContinueOnError)
+ f.Usage = func() {
+ if err := leetgode.ShowUsage(stdout); err != nil {
+ fmt.Fprintf(stderr, "failed show useage: %v\n", err)
  }
- return
  }
- // TODO: set os.Stderr if set debug mode
- log.SetOutput(ioutil.Discard)
+ var v bool
+ f.BoolVar(&v, "v", false, "show debug print")
+ if err := f.Parse(args[2:]); err == flag.ErrHelp {
+ return 1
+ } else if err != nil {
+ fmt.Fprintf(stderr, "%s with invalid args: %v\n", sub, err)
+ return 1
+ }
+
+ log.SetOutput(stderr)
+ if !v {
+ log.SetOutput(ioutil.Discard)
+ }
 
  if cmd, ok := leetgode.CmdMap[leetgode.CmdName(sub)]; ok {
- args := flag.Args()[1:]
+ args := f.Args()
  if len(args) != cmd.MaxArg() {
- fmt.Printf("%s expects %d options, but %d options\n", cmd.Name(), cmd.MaxArg(), len(args))
- os.Exit(1)
+ fmt.Fprintf(stderr, "%s expects %d options, but %d options\n", cmd.Name(), cmd.MaxArg(), len(args))
+ return 1
  }
  if err := cmd.Run(context.Background(), args); err != nil {
- log.Printf("main: err %v", err)
- os.Exit(1)
+ fmt.Fprintf(stderr, "main: err %v", err)
+ return 1
  }
  } else {
- log.Printf("unknown command %q", sub)
- os.Exit(1)
+ fmt.Fprintf(stderr, "unknown command %q", sub)
+ return 1
  }
+ return 0
 }