adds alternative error handling to readme

This commit is contained in:
Austin Riendeau 2015-10-26 22:39:06 -06:00 committed by spf13
parent 7290a944e4
commit bc980b80a1

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@ -85,7 +85,7 @@ A Command has the following structure:
### Flags ### Flags
A Flag is a way to modify the behavior of an command. Cobra supports A Flag is a way to modify the behavior of an command. Cobra supports
fully posix compliant flags as well as the go flag package. fully posix compliant flags as well as the go flag package.
A Cobra command can define flags that persist through to children commands A Cobra command can define flags that persist through to children commands
and flags that are only available to that command. and flags that are only available to that command.
@ -306,7 +306,7 @@ around it. In fact you can provide your own if you want.
You can provide your own Help command or you own template for the default command to use. You can provide your own Help command or you own template for the default command to use.
The default help command is The default help command is
func (c *Command) initHelp() { func (c *Command) initHelp() {
if c.helpCommand == nil { if c.helpCommand == nil {
@ -448,6 +448,48 @@ func main() {
} }
``` ```
## Alternative Error Handling
Cobra also has functions where the return signature is an error. This allows for errors to bubble up to the top, providing a way to handle the errors in one location. The current list of functions that return an error is:
* PersistentPreRunE
* PreRunE
* RunE
* PostRunE
* PersistentPostRunE
**Example Usage using RunE:**
```go
package main
import (
"errors"
"log"
"github.com/spf13/cobra"
)
func main() {
var rootCmd = &cobra.Command{
Use: "hugo",
Short: "Hugo is a very fast static site generator",
Long: `A Fast and Flexible Static Site Generator built with
love by spf13 and friends in Go.
Complete documentation is available at http://hugo.spf13.com`,
RunE: func(cmd *cobra.Command, args []string) error {
// Do Stuff Here
return errors.New("some random error")
},
}
if err := rootCmd.Execute(); err != nil {
log.Fatal(err)
}
}
```
## Suggestions when "unknown command" happens ## Suggestions when "unknown command" happens
Cobra will print automatic suggestions when "unknown command" errors happen. This allows Cobra to behavior similarly to the `git` command when a typo happens. For example: Cobra will print automatic suggestions when "unknown command" errors happen. This allows Cobra to behavior similarly to the `git` command when a typo happens. For example:
@ -468,7 +510,7 @@ If you need to disable suggestions or tweak the string distance in your command,
command.DisableSuggestions = true command.DisableSuggestions = true
or or
command.SuggestionsMinimumDistance = 1 command.SuggestionsMinimumDistance = 1
@ -552,4 +594,3 @@ Cobra is released under the Apache 2.0 license. See [LICENSE.txt](https://github
[![Bitdeli Badge](https://d2weczhvl823v0.cloudfront.net/spf13/cobra/trend.png)](https://bitdeli.com/free "Bitdeli Badge") [![Bitdeli Badge](https://d2weczhvl823v0.cloudfront.net/spf13/cobra/trend.png)](https://bitdeli.com/free "Bitdeli Badge")