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

@ -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).
### 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
Validation of positional arguments can be specified using the `Args` field

View file

@ -494,17 +494,20 @@ func (c *Command) GenBashCompletionFile(filename string) error {
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 {
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 {
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 {
return flags.SetAnnotation(name, BashCompOneRequiredFlag, []string{"true"})
}