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@ -19,13 +19,34 @@ Many of the most widely used Go projects are built using Cobra including:
* [GiantSwarm's swarm](https://github.com/giantswarm/cli)
* [Nanobox](https://github.com/nanobox-io/nanobox)/[Nanopack](https://github.com/nanopack)
* [rclone](http://rclone.org/)
* [nehm](https://github.com/bogem/nehm)
[![Build Status](https://travis-ci.org/spf13/cobra.svg "Travis CI status")](https://travis-ci.org/spf13/cobra)
[![CircleCI status](https://circleci.com/gh/spf13/cobra.png?circle-token=:circle-token "CircleCI status")](https://circleci.com/gh/spf13/cobra)
[![GoDoc](https://godoc.org/github.com/spf13/cobra?status.svg)](https://godoc.org/github.com/spf13/cobra)
![cobra](https://cloud.githubusercontent.com/assets/173412/10911369/84832a8e-8212-11e5-9f82-cc96660a4794.gif)
# Table of Contents
- [Overview](#overview)
- [Concepts](#concepts)
* [Commands](#commands)
* [Flags](#flags)
- [Installing](#installing)
- [Getting Started](#getting-started)
* [Using the Cobra Generator](#using-the-cobra-generator)
* [Using the Cobra Library](#using-the-cobra-library)
* [Working with Flags](#working-with-flags)
* [Positional and Custom Arguments](#positional-and-custom-arguments)
* [Example](#example)
* [Help Command](#help-command)
* [Usage Message](#usage-message)
* [PreRun and PostRun Hooks](#prerun-and-postrun-hooks)
* [Suggestions when "unknown command" happens](#suggestions-when-unknown-command-happens)
* [Generating Markdown-formatted docs](#generating-markdown-formatted-docs)
* [Generating man pages](#generating-man-pages)
* [Generating bash completions](#generating-bash-completions)
- [Contributing](#contributing)
- [License](#license)
# Overview
@ -43,7 +64,6 @@ Cobra provides:
* Easy generation of applications & commands with `cobra init appname` & `cobra add cmdname`
* Intelligent suggestions (`app srver`... did you mean `app server`?)
* Automatic help generation for commands and flags
* Automatic detailed help for `app help [command]`
* Automatic help flag recognition of `-h`, `--help`, etc.
* Automatically generated bash autocomplete for your application
* Automatically generated man pages for your application
@ -51,16 +71,6 @@ Cobra provides:
* The flexibility to define your own help, usage, etc.
* Optional tight integration with [viper](http://github.com/spf13/viper) for 12-factor apps
Cobra has an exceptionally clean interface and simple design without needless
constructors or initialization methods.
Applications built with Cobra commands are designed to be as user-friendly as
possible. Flags can be placed before or after the command (as long as a
confusing space isn’t provided). Both short and long flags can be used. A
command need not even be fully typed. Help is automatically generated and
available for the application or for a specific command using either the help
command or the `--help` flag.
# Concepts
Cobra is built on a structure of commands, arguments & flags.
@ -93,20 +103,11 @@ have children commands and optionally run an action.
In the example above, 'server' is the command.
A Command has the following structure:
```go
type Command struct {
Use string // The one-line usage message.
Short string // The short description shown in the 'help' output.
Long string // The long message shown in the 'help <this-command>' output.
Run func(cmd *Command, args []string) // Run runs the command.
}
```
[More about cobra.Command](https://godoc.org/github.com/spf13/cobra#Command)
## Flags
A Flag is a way to modify the behavior of a command. Cobra supports
A flag is a way to modify the behavior of a command. Cobra supports
fully POSIX-compliant flags as well as the Go [flag package](https://golang.org/pkg/flag/).
A Cobra command can define flags that persist through to children commands
and flags that are only available to that command.
@ -170,106 +171,14 @@ func main() {
Cobra provides its own program that will create your application and add any
commands you want. It's the easiest way to incorporate Cobra into your application.
In order to use the cobra command, compile it using the following command:
[Here](https://github.com/spf13/cobra/cobra/README.md) you can find more information about it.
go get github.com/spf13/cobra/cobra
This will create the cobra executable under your `$GOPATH/bin` directory.
### cobra init
The `cobra init [yourApp]` command will create your initial application code
for you. It is a very powerful application that will populate your program with
the right structure so you can immediately enjoy all the benefits of Cobra. It
will also automatically apply the license you specify to your application.
Cobra init is pretty smart. You can provide it a full path, or simply a path
similar to what is expected in the import.
```
cobra init github.com/spf13/newAppName
```
### cobra add
Once an application is initialized Cobra can create additional commands for you.
Let's say you created an app and you wanted the following commands for it:
* app serve
* app config
* app config create
In your project directory (where your main.go file is) you would run the following:
```
cobra add serve
cobra add config
cobra add create -p 'configCmd'
```
*Note: Use camelCase (not snake_case/snake-case) for command names.
Otherwise, you will encounter errors.
For example, `cobra add add-user` is incorrect, but `cobra add addUser` is valid.*
Once you have run these three commands you would have an app structure similar to
the following:
```
▾ app/
▾ cmd/
serve.go
config.go
create.go
main.go
```
At this point you can run `go run main.go` and it would run your app. `go run
main.go serve`, `go run main.go config`, `go run main.go config create` along
with `go run main.go help serve`, etc. would all work.
Obviously you haven't added your own code to these yet. The commands are ready
for you to give them their tasks. Have fun!
### Configuring the cobra generator
The Cobra generator will be easier to use if you provide a simple configuration
file which will help you eliminate providing a bunch of repeated information in
flags over and over.
An example ~/.cobra.yaml file:
```yaml
author: Steve Francia <spf@spf13.com>
license: MIT
```
You can specify no license by setting `license` to `none` or you can specify
a custom license:
```yaml
license:
header: This file is part of {{ .appName }}.
text: |
{{ .copyright }}
This is my license. There are many like it, but this one is mine.
My license is my best friend. It is my life. I must master it as I must
master my life.
```
You can also use built-in licenses. For example, **GPLv2**, **GPLv3**, **LGPL**,
**AGPL**, **MIT**, **2-Clause BSD** or **3-Clause BSD**.
## Manually implementing Cobra
## Using the Cobra Library
To manually implement Cobra you need to create a bare main.go file and a RootCmd file.
You will optionally provide additional commands as you see fit.
### Create the root command
The root command represents your binary itself.
#### Manually create rootCmd
### Create rootCmd
Cobra doesn't require any special constructors. Simply create your commands.
@ -400,17 +309,6 @@ var versionCmd = &cobra.Command{
}
```
### Attach command to its parent
If you notice in the above example we attach the command to its parent. In
this case the parent is the rootCmd. In this example we are attaching it to the
root, but commands can be attached at any level.
```go
RootCmd.AddCommand(versionCmd)
```
## Working with Flags
Flags provide modifiers to control how the action command operates.
@ -569,7 +467,7 @@ a count and a string.`,
For a more complete example of a larger application, please checkout [Hugo](http://gohugo.io/).
## The Help Command
## Help Command
Cobra automatically adds a help command to your application when you have subcommands.
This will be called when a user runs 'app help'. Additionally, help will also
@ -582,60 +480,28 @@ create' is called. Every command will automatically have the '--help' flag adde
The following output is automatically generated by Cobra. Nothing beyond the
command and flag definitions are needed.
> hugo help
$ cobra help
hugo is the main command, used to build your Hugo site.
Hugo is a Fast and Flexible Static Site Generator
built with love by spf13 and friends in Go.
Complete documentation is available at http://gohugo.io/.
Cobra is a CLI library for Go that empowers applications.
This application is a tool to generate the needed files
to quickly create a Cobra application.
Usage:
hugo [flags]
hugo [command]
cobra [command]
Available Commands:
server Hugo runs its own webserver to render the files
version Print the version number of Hugo
config Print the site configuration
check Check content in the source directory
benchmark Benchmark hugo by building a site a number of times.
convert Convert your content to different formats
new Create new content for your site
list Listing out various types of content
undraft Undraft changes the content's draft status from 'True' to 'False'
genautocomplete Generate shell autocompletion script for Hugo
gendoc Generate Markdown documentation for the Hugo CLI.
genman Generate man page for Hugo
import Import your site from others.
add Add a command to a Cobra Application
help Help about any command
init Initialize a Cobra Application
Flags:
-b, --baseURL="": hostname (and path) to the root, e.g. http://spf13.com/
-D, --buildDrafts[=false]: include content marked as draft
-F, --buildFuture[=false]: include content with publishdate in the future
--cacheDir="": filesystem path to cache directory. Defaults: $TMPDIR/hugo_cache/
--canonifyURLs[=false]: if true, all relative URLs will be canonicalized using baseURL
--config="": config file (default is path/config.yaml|json|toml)
-d, --destination="": filesystem path to write files to
--disableRSS[=false]: Do not build RSS files
--disableSitemap[=false]: Do not build Sitemap file
--editor="": edit new content with this editor, if provided
--ignoreCache[=false]: Ignores the cache directory for reading but still writes to it
--log[=false]: Enable Logging
--logFile="": Log File path (if set, logging enabled automatically)
--noTimes[=false]: Don't sync modification time of files
--pluralizeListTitles[=true]: Pluralize titles in lists using inflect
--preserveTaxonomyNames[=false]: Preserve taxonomy names as written ("Gérard Depardieu" vs "gerard-depardieu")
-s, --source="": filesystem path to read files relative from
--stepAnalysis[=false]: display memory and timing of different steps of the program
-t, --theme="": theme to use (located in /themes/THEMENAME/)
--uglyURLs[=false]: if true, use /filename.html instead of /filename/
-v, --verbose[=false]: verbose output
--verboseLog[=false]: verbose logging
-w, --watch[=false]: watch filesystem for changes and recreate as needed
-a, --author string author name for copyright attribution (default "YOUR NAME")
--config string config file (default is $HOME/.cobra.yaml)
-h, --help help for cobra
-l, --license string name of license for the project
--viper use Viper for configuration (default true)
Use "hugo [command] --help" for more information about a command.
Use "cobra [command] --help" for more information about a command.
Help is just a command like any other. There is no special logic or behavior
@ -643,36 +509,18 @@ around it. In fact, you can provide your own if you want.
### Defining your own help
You can provide your own Help command or your own template for the default command to use.
The default help command is
You can provide your own Help command or your own template for the default command to use
with followind functions:
```go
func (c *Command) initHelp() {
if c.helpCommand == nil {
c.helpCommand = &Command{
Use: "help [command]",
Short: "Help about any command",
Long: `Help provides help for any command in the application.
Simply type ` + c.Name() + ` help [path to command] for full details.`,
Run: c.HelpFunc(),
}
}
c.AddCommand(c.helpCommand)
}
```
You can provide your own command, function or template through the following methods:
```go
command.SetHelpCommand(cmd *Command)
command.SetHelpFunc(f func(*Command, []string))
command.SetHelpTemplate(s string)
cmd.SetHelpCommand(cmd *Command)
cmd.SetHelpFunc(f func(*Command, []string))
cmd.SetHelpTemplate(s string)
```
The latter two will also apply to any children commands.
## Usage
## Usage Message
When the user provides an invalid flag or invalid command, Cobra responds by
showing the user the 'usage'.
@ -681,71 +529,35 @@ showing the user the 'usage'.
You may recognize this from the help above. That's because the default help
embeds the usage as part of its output.
$ cobra --invalid
Error: unknown flag: --invalid
Usage:
hugo [flags]
hugo [command]
cobra [command]
Available Commands:
server Hugo runs its own webserver to render the files
version Print the version number of Hugo
config Print the site configuration
check Check content in the source directory
benchmark Benchmark hugo by building a site a number of times.
convert Convert your content to different formats
new Create new content for your site
list Listing out various types of content
undraft Undraft changes the content's draft status from 'True' to 'False'
genautocomplete Generate shell autocompletion script for Hugo
gendoc Generate Markdown documentation for the Hugo CLI.
genman Generate man page for Hugo
import Import your site from others.
add Add a command to a Cobra Application
help Help about any command
init Initialize a Cobra Application
Flags:
-b, --baseURL="": hostname (and path) to the root, e.g. http://spf13.com/
-D, --buildDrafts[=false]: include content marked as draft
-F, --buildFuture[=false]: include content with publishdate in the future
--cacheDir="": filesystem path to cache directory. Defaults: $TMPDIR/hugo_cache/
--canonifyURLs[=false]: if true, all relative URLs will be canonicalized using baseURL
--config="": config file (default is path/config.yaml|json|toml)
-d, --destination="": filesystem path to write files to
--disableRSS[=false]: Do not build RSS files
--disableSitemap[=false]: Do not build Sitemap file
--editor="": edit new content with this editor, if provided
--ignoreCache[=false]: Ignores the cache directory for reading but still writes to it
--log[=false]: Enable Logging
--logFile="": Log File path (if set, logging enabled automatically)
--noTimes[=false]: Don't sync modification time of files
--pluralizeListTitles[=true]: Pluralize titles in lists using inflect
--preserveTaxonomyNames[=false]: Preserve taxonomy names as written ("Gérard Depardieu" vs "gerard-depardieu")
-s, --source="": filesystem path to read files relative from
--stepAnalysis[=false]: display memory and timing of different steps of the program
-t, --theme="": theme to use (located in /themes/THEMENAME/)
--uglyURLs[=false]: if true, use /filename.html instead of /filename/
-v, --verbose[=false]: verbose output
--verboseLog[=false]: verbose logging
-w, --watch[=false]: watch filesystem for changes and recreate as needed
-a, --author string author name for copyright attribution (default "YOUR NAME")
--config string config file (default is $HOME/.cobra.yaml)
-h, --help help for cobra
-l, --license string name of license for the project
--viper use Viper for configuration (default true)
Use "cobra [command] --help" for more information about a command.
### Defining your own usage
You can provide your own usage function or template for Cobra to use.
The default usage function is:
```go
return func(c *Command) error {
err := tmpl(c.Out(), c.UsageTemplate(), c)
return err
}
```
Like help, the function and template are overridable through public methods:
```go
command.SetUsageFunc(f func(*Command) error)
command.SetUsageTemplate(s string)
cmd.SetUsageFunc(f func(*Command) error)
cmd.SetUsageTemplate(s string)
```
## PreRun or PostRun Hooks
## PreRun and PostRun Hooks
It is possible to run functions before or after the main `Run` function of your command. The `PersistentPreRun` and `PreRun` functions will be executed before `Run`. `PersistentPostRun` and `PostRun` will be executed after `Run`. The `Persistent*Run` functions will be inherited by children if they do not declare their own. These functions are run in the following order:
@ -815,51 +627,19 @@ func main() {
}
```
Output:
```
Inside rootCmd PersistentPreRun with args: []
Inside rootCmd PreRun with args: []
Inside rootCmd Run with args: []
Inside rootCmd PostRun with args: []
Inside rootCmd PersistentPostRun with args: []
## 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
If you would like to silence the default `error` and `usage` output in favor of your own, you can set `SilenceUsage`
and `SilenceErrors` to `true` on the command. A child command respects these flags if they are set on the parent
command.
**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)
}
}
Inside rootCmd PersistentPreRun with args: [arg1 arg2]
Inside subCmd PreRun with args: [arg1 arg2]
Inside subCmd Run with args: [arg1 arg2]
Inside subCmd PostRun with args: [arg1 arg2]
Inside subCmd PersistentPostRun with args: [arg1 arg2]
```
## Suggestions when "unknown command" happens
@ -902,41 +682,28 @@ Did you mean this?
Run 'kubectl help' for usage.
```
## Generating Markdown-formatted documentation for your command
## Generating Markdown-formatted docs
Cobra can generate a Markdown-formatted document based on the subcommands, flags, etc. A simple example of how to do this for your command can be found in [Markdown Docs](doc/md_docs.md).
## Generating man pages for your command
## Generating man pages
Cobra can generate a man page based on the subcommands, flags, etc. A simple example of how to do this for your command can be found in [Man Docs](doc/man_docs.md).
## Generating bash completions for your command
## Generating bash completions
Cobra can generate a bash-completion file. If you add more information to your command, these completions can be amazingly powerful and flexible. Read more about it in [Bash Completions](bash_completions.md).
## Extensions
Libraries for extending Cobra:
* [cmdns](https://github.com/gosuri/cmdns): Enables name spacing a command's immediate children. It provides an alternative way to structure subcommands, similar to `heroku apps:create` and `ovrclk clusters:launch`.
## Contributing
# Contributing
1. Fork it
2. Create your feature branch (`git checkout -b my-new-feature`)
3. Commit your changes (`git commit -am 'Add some feature'`)
4. Push to the branch (`git push origin my-new-feature`)
5. Create new Pull Request
2. Download your fork to your PC (`git clone https://github.com/your_username/cobra && cd cobra`)
3. Create your feature branch (`git checkout -b my-new-feature`)
4. Make changes and add them (`git add .`)
5. Commit your changes (`git commit -m 'Add some feature'`)
6. Push to the branch (`git push origin my-new-feature`)
7. Create new pull request
## Contributors
Names in no particular order:
* [spf13](https://github.com/spf13),
[eparis](https://github.com/eparis),
[bep](https://github.com/bep), and many more!
## License
# License
Cobra is released under the Apache 2.0 license. See [LICENSE.txt](https://github.com/spf13/cobra/blob/master/LICENSE.txt)

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@ -0,0 +1,94 @@
# Cobra Generator
Cobra provides its own program that will create your application and add any
commands you want. It's the easiest way to incorporate Cobra into your application.
In order to use the cobra command, compile it using the following command:
go get github.com/spf13/cobra/cobra
This will create the cobra executable under your `$GOPATH/bin` directory.
### cobra init
The `cobra init [app]` command will create your initial application code
for you. It is a very powerful application that will populate your program with
the right structure so you can immediately enjoy all the benefits of Cobra. It
will also automatically apply the license you specify to your application.
Cobra init is pretty smart. You can provide it a full path, or simply a path
similar to what is expected in the import.
```
cobra init github.com/spf13/newApp
```
### cobra add
Once an application is initialized Cobra can create additional commands for you.
Let's say you created an app and you wanted the following commands for it:
* app serve
* app config
* app config create
In your project directory (where your main.go file is) you would run the following:
```
cobra add serve
cobra add config
cobra add create -p 'configCmd'
```
*Note: Use camelCase (not snake_case/snake-case) for command names.
Otherwise, you will encounter errors.
For example, `cobra add add-user` is incorrect, but `cobra add addUser` is valid.*
Once you have run these three commands you would have an app structure similar to
the following:
```
▾ app/
▾ cmd/
serve.go
config.go
create.go
main.go
```
At this point you can run `go run main.go` and it would run your app. `go run
main.go serve`, `go run main.go config`, `go run main.go config create` along
with `go run main.go help serve`, etc. would all work.
Obviously you haven't added your own code to these yet. The commands are ready
for you to give them their tasks. Have fun!
### Configuring the cobra generator
The Cobra generator will be easier to use if you provide a simple configuration
file which will help you eliminate providing a bunch of repeated information in
flags over and over.
An example ~/.cobra.yaml file:
```yaml
author: Steve Francia <spf@spf13.com>
license: MIT
```
You can specify no license by setting `license` to `none` or you can specify
a custom license:
```yaml
license:
header: This file is part of {{ .appName }}.
text: |
{{ .copyright }}
This is my license. There are many like it, but this one is mine.
My license is my best friend. It is my life. I must master it as I must
master my life.
```
You can also use built-in licenses. For example, **GPLv2**, **GPLv3**, **LGPL**,
**AGPL**, **MIT**, **2-Clause BSD** or **3-Clause BSD**.