85 lines
2.1 KiB
Go
85 lines
2.1 KiB
Go
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package rcli
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import (
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"fmt"
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"io"
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"reflect"
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"flag"
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"log"
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"strings"
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"errors"
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)
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type Service interface {
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Name() string
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Help() string
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}
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type Cmd func(io.ReadCloser, io.Writer, ...string) error
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type CmdMethod func(Service, io.ReadCloser, io.Writer, ...string) error
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func call(service Service, stdin io.ReadCloser, stdout io.Writer, args ...string) error {
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flags := flag.NewFlagSet("main", flag.ContinueOnError)
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flags.SetOutput(stdout)
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flags.Usage = func() { stdout.Write([]byte(service.Help())) }
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if err := flags.Parse(args); err != nil {
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return err
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}
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cmd := flags.Arg(0)
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log.Printf("%s\n", strings.Join(append(append([]string{service.Name()}, cmd), flags.Args()[1:]...), " "))
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if cmd == "" {
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cmd = "help"
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}
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method := getMethod(service, cmd)
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if method != nil {
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return method(stdin, stdout, args[1:]...)
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}
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return errors.New("No such command: " + cmd)
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}
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func getMethod(service Service, name string) Cmd {
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if name == "help" {
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return func(stdin io.ReadCloser, stdout io.Writer, args ...string) error {
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if len(args) == 0 {
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stdout.Write([]byte(service.Help()))
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} else {
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if method := getMethod(service, args[0]); method == nil {
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return errors.New("No such command: " + args[0])
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} else {
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method(stdin, stdout, "--help")
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}
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}
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return nil
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}
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}
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methodName := "Cmd"+strings.ToUpper(name[:1])+strings.ToLower(name[1:])
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method, exists := reflect.TypeOf(service).MethodByName(methodName)
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if !exists {
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return nil
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}
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return func(stdin io.ReadCloser, stdout io.Writer, args ...string) error {
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ret := method.Func.CallSlice([]reflect.Value{
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reflect.ValueOf(service),
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reflect.ValueOf(stdin),
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reflect.ValueOf(stdout),
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reflect.ValueOf(args),
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})[0].Interface()
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if ret == nil {
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return nil
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}
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return ret.(error)
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}
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}
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func Subcmd(output io.Writer, name, signature, description string) *flag.FlagSet {
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flags := flag.NewFlagSet(name, flag.ContinueOnError)
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flags.SetOutput(output)
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flags.Usage = func() {
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fmt.Fprintf(output, "\nUsage: docker %s %s\n\n%s\n\n", name, signature, description)
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flags.PrintDefaults()
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}
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return flags
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}
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