vendor/github.com/mitchellh/cli/command.go

   1 package cli
   2
   3 import (
   4         "github.com/posener/complete"
   5 )
   6
   7 const (
   8         // RunResultHelp is a value that can be returned from Run to signal
   9         // to the CLI to render the help output.
  10         RunResultHelp = -18511
  11 )
  12
  13 // A command is a runnable sub-command of a CLI.
  14 type Command interface {
  15         // Help should return long-form help text that includes the command-line
  16         // usage, a brief few sentences explaining the function of the command,
  17         // and the complete list of flags the command accepts.
  18         Help() string
  19
  20         // Run should run the actual command with the given CLI instance and
  21         // command-line arguments. It should return the exit status when it is
  22         // finished.
  23         //
  24         // There are a handful of special exit codes this can return documented
  25         // above that change behavior.
  26         Run(args []string) int
  27
  28         // Synopsis should return a one-line, short synopsis of the command.
  29         // This should be less than 50 characters ideally.
  30         Synopsis() string
  31 }
  32
  33 // CommandAutocomplete is an extension of Command that enables fine-grained
  34 // autocompletion. Subcommand autocompletion will work even if this interface
  35 // is not implemented. By implementing this interface, more advanced
  36 // autocompletion is enabled.
  37 type CommandAutocomplete interface {
  38         // AutocompleteArgs returns the argument predictor for this command.
  39         // If argument completion is not supported, this should return
  40         // complete.PredictNothing.
  41         AutocompleteArgs() complete.Predictor
  42
  43         // AutocompleteFlags returns a mapping of supported flags and autocomplete
  44         // options for this command. The map key for the Flags map should be the
  45         // complete flag such as "-foo" or "--foo".
  46         AutocompleteFlags() complete.Flags
  47 }
  48
  49 // CommandHelpTemplate is an extension of Command that also has a function
  50 // for returning a template for the help rather than the help itself. In
  51 // this scenario, both Help and HelpTemplate should be implemented.
  52 //
  53 // If CommandHelpTemplate isn't implemented, the Help is output as-is.
  54 type CommandHelpTemplate interface {
  55         // HelpTemplate is the template in text/template format to use for
  56         // displaying the Help. The keys available are:
  57         //
  58         //   * ".Help" - The help text itself
  59         //   * ".Subcommands"
  60         //
  61         HelpTemplate() string
  62 }
  63
  64 // CommandFactory is a type of function that is a factory for commands.
  65 // We need a factory because we may need to setup some state on the
  66 // struct that implements the command itself.
  67 type CommandFactory func() (Command, error)