Add usage example for required flags (#627)

* Add usage example for required flags

* Explain new behavior in MarkFlagRequired godocs
This commit is contained in:
Jake Dodd 2018-02-05 11:53:53 -08:00 committed by Eric Paris
parent eb58983359
commit c2bbfaa12d
2 changed files with 17 additions and 5 deletions

View File

@ -337,8 +337,8 @@ rootCmd.Flags().StringVarP(&Source, "source", "s", "", "Source directory to read
### Local Flag on Parent Commands ### Local Flag on Parent Commands
By default Cobra only parses local flags on the target command, any local flags on By default Cobra only parses local flags on the target command, any local flags on
parent commands are ignored. By enabling `Command.TraverseChildren` Cobra will parent commands are ignored. By enabling `Command.TraverseChildren` Cobra will
parse local flags on each command before executing the target command. parse local flags on each command before executing the target command.
```go ```go
@ -366,6 +366,15 @@ when the `--author` flag is not provided by user.
More in [viper documentation](https://github.com/spf13/viper#working-with-flags). More in [viper documentation](https://github.com/spf13/viper#working-with-flags).
### Required flags
Flags are optional by default. If instead you wish your command to report an error
when a flag has not been set, mark it as required:
```go
rootCmd.Flags().StringVarP(&Region, "region", "r", "", "AWS region (required)")
rootCmd.MarkFlagRequired("region")
```
## Positional and Custom Arguments ## Positional and Custom Arguments
Validation of positional arguments can be specified using the `Args` field Validation of positional arguments can be specified using the `Args` field

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@ -494,17 +494,20 @@ func (c *Command) GenBashCompletionFile(filename string) error {
return c.GenBashCompletion(outFile) return c.GenBashCompletion(outFile)
} }
// MarkFlagRequired adds the BashCompOneRequiredFlag annotation to the named flag, if it exists. // MarkFlagRequired adds the BashCompOneRequiredFlag annotation to the named flag if it exists,
// and causes your command to report an error if invoked without the flag.
func (c *Command) MarkFlagRequired(name string) error { func (c *Command) MarkFlagRequired(name string) error {
return MarkFlagRequired(c.Flags(), name) return MarkFlagRequired(c.Flags(), name)
} }
// MarkPersistentFlagRequired adds the BashCompOneRequiredFlag annotation to the named persistent flag, if it exists. // MarkPersistentFlagRequired adds the BashCompOneRequiredFlag annotation to the named persistent flag if it exists,
// and causes your command to report an error if invoked without the flag.
func (c *Command) MarkPersistentFlagRequired(name string) error { func (c *Command) MarkPersistentFlagRequired(name string) error {
return MarkFlagRequired(c.PersistentFlags(), name) return MarkFlagRequired(c.PersistentFlags(), name)
} }
// MarkFlagRequired adds the BashCompOneRequiredFlag annotation to the named flag in the flag set, if it exists. // MarkFlagRequired adds the BashCompOneRequiredFlag annotation to the named flag if it exists,
// and causes your command to report an error if invoked without the flag.
func MarkFlagRequired(flags *pflag.FlagSet, name string) error { func MarkFlagRequired(flags *pflag.FlagSet, name string) error {
return flags.SetAnnotation(name, BashCompOneRequiredFlag, []string{"true"}) return flags.SetAnnotation(name, BashCompOneRequiredFlag, []string{"true"})
} }