README ¶
cli
cli is a simple, fast, and fun package for building command line apps in Go. The goal is to enable developers to write fast and distributable command line applications in an expressive way.
Overview
Command line apps are usually so tiny that there is absolutely no reason why your code should not be self-documenting. Things like generating help text and parsing command flags/options should not hinder productivity when writing a command line app.
This is where cli comes into play. cli makes command line programming fun, organized, and expressive!
Installation
Make sure you have a working Go environment (go 1.1+ is required). See the install instructions.
To install cli, simply run:
$ go get github.com/codegangsta/cli
Make sure your PATH
includes to the $GOPATH/bin
directory so your commands can be easily used:
export PATH=$PATH:$GOPATH/bin
Getting Started
One of the philosophies behind cli is that an API should be playful and full of discovery. So a cli app can be as little as one line of code in main()
.
package main
import (
"os"
"github.com/codegangsta/cli"
)
func main() {
cli.NewApp().Run(os.Args)
}
This app will run and show help text, but is not very useful. Let's give an action to execute and some help documentation:
package main
import (
"fmt"
"os"
"github.com/codegangsta/cli"
)
func main() {
app := cli.NewApp()
app.Name = "boom"
app.Usage = "make an explosive entrance"
app.Action = func(c *cli.Context) error {
fmt.Println("boom! I say!")
return nil
}
app.Run(os.Args)
}
Running this already gives you a ton of functionality, plus support for things like subcommands and flags, which are covered below.
Example
Being a programmer can be a lonely job. Thankfully by the power of automation that is not the case! Let's create a greeter app to fend off our demons of loneliness!
Start by creating a directory named greet
, and within it, add a file, greet.go
with the following code in it:
package main
import (
"fmt"
"os"
"github.com/codegangsta/cli"
)
func main() {
app := cli.NewApp()
app.Name = "greet"
app.Usage = "fight the loneliness!"
app.Action = func(c *cli.Context) error {
fmt.Println("Hello friend!")
return nil
}
app.Run(os.Args)
}
Install our command to the $GOPATH/bin
directory:
$ go install
Finally run our new command:
$ greet
Hello friend!
cli also generates neat help text:
$ greet help
NAME:
greet - fight the loneliness!
USAGE:
greet [global options] command [command options] [arguments...]
VERSION:
0.0.0
COMMANDS:
help, h Shows a list of commands or help for one command
GLOBAL OPTIONS
--version Shows version information
Arguments
You can lookup arguments by calling the Args
function on cli.Context
.
...
app.Action = func(c *cli.Context) error {
fmt.Println("Hello", c.Args()[0])
return nil
}
...
Flags
Setting and querying flags is simple.
...
app.Flags = []cli.Flag {
cli.StringFlag{
Name: "lang",
Value: "english",
Usage: "language for the greeting",
},
}
app.Action = func(c *cli.Context) error {
name := "someone"
if c.NArg() > 0 {
name = c.Args()[0]
}
if c.String("lang") == "spanish" {
fmt.Println("Hola", name)
} else {
fmt.Println("Hello", name)
}
return nil
}
...
You can also set a destination variable for a flag, to which the content will be scanned.
...
var language string
app.Flags = []cli.Flag {
cli.StringFlag{
Name: "lang",
Value: "english",
Usage: "language for the greeting",
Destination: &language,
},
}
app.Action = func(c *cli.Context) error {
name := "someone"
if c.NArg() > 0 {
name = c.Args()[0]
}
if language == "spanish" {
fmt.Println("Hola", name)
} else {
fmt.Println("Hello", name)
}
return nil
}
...
See full list of flags at http://godoc.org/github.com/codegangsta/cli
Placeholder Values
Sometimes it's useful to specify a flag's value within the usage string itself. Such placeholders are indicated with back quotes.
For example this:
cli.StringFlag{
Name: "config, c",
Usage: "Load configuration from `FILE`",
}
Will result in help output like:
--config FILE, -c FILE Load configuration from FILE
Note that only the first placeholder is used. Subsequent back-quoted words will be left as-is.
Alternate Names
You can set alternate (or short) names for flags by providing a comma-delimited list for the Name
. e.g.
app.Flags = []cli.Flag {
cli.StringFlag{
Name: "lang, l",
Value: "english",
Usage: "language for the greeting",
},
}
That flag can then be set with --lang spanish
or -l spanish
. Note that giving two different forms of the same flag in the same command invocation is an error.
Values from the Environment
You can also have the default value set from the environment via EnvVar
. e.g.
app.Flags = []cli.Flag {
cli.StringFlag{
Name: "lang, l",
Value: "english",
Usage: "language for the greeting",
EnvVar: "APP_LANG",
},
}
The EnvVar
may also be given as a comma-delimited "cascade", where the first environment variable that resolves is used as the default.
app.Flags = []cli.Flag {
cli.StringFlag{
Name: "lang, l",
Value: "english",
Usage: "language for the greeting",
EnvVar: "LEGACY_COMPAT_LANG,APP_LANG,LANG",
},
}
Values from alternate input sources (YAML and others)
There is a separate package altsrc that adds support for getting flag values from other input sources like YAML.
In order to get values for a flag from an alternate input source the following code would be added to wrap an existing cli.Flag like below:
altsrc.NewIntFlag(cli.IntFlag{Name: "test"})
Initialization must also occur for these flags. Below is an example initializing getting data from a yaml file below.
command.Before = altsrc.InitInputSourceWithContext(command.Flags, NewYamlSourceFromFlagFunc("load"))
The code above will use the "load" string as a flag name to get the file name of a yaml file from the cli.Context. It will then use that file name to initialize the yaml input source for any flags that are defined on that command. As a note the "load" flag used would also have to be defined on the command flags in order for this code snipped to work.
Currently only YAML files are supported but developers can add support for other input sources by implementing the altsrc.InputSourceContext for their given sources.
Here is a more complete sample of a command using YAML support:
command := &cli.Command{
Name: "test-cmd",
Aliases: []string{"tc"},
Usage: "this is for testing",
Description: "testing",
Action: func(c *cli.Context) error {
// Action to run
return nil
},
Flags: []cli.Flag{
NewIntFlag(cli.IntFlag{Name: "test"}),
cli.StringFlag{Name: "load"}},
}
command.Before = InitInputSourceWithContext(command.Flags, NewYamlSourceFromFlagFunc("load"))
err := command.Run(c)
Subcommands
Subcommands can be defined for a more git-like command line app.
...
app.Commands = []cli.Command{
{
Name: "add",
Aliases: []string{"a"},
Usage: "add a task to the list",
Action: func(c *cli.Context) error {
fmt.Println("added task: ", c.Args().First())
return nil
},
},
{
Name: "complete",
Aliases: []string{"c"},
Usage: "complete a task on the list",
Action: func(c *cli.Context) error {
fmt.Println("completed task: ", c.Args().First())
return nil
},
},
{
Name: "template",
Aliases: []string{"r"},
Usage: "options for task templates",
Subcommands: []cli.Command{
{
Name: "add",
Usage: "add a new template",
Action: func(c *cli.Context) error {
fmt.Println("new task template: ", c.Args().First())
return nil
},
},
{
Name: "remove",
Usage: "remove an existing template",
Action: func(c *cli.Context) error {
fmt.Println("removed task template: ", c.Args().First())
return nil
},
},
},
},
}
...
Subcommands categories
For additional organization in apps that have many subcommands, you can associate a category for each command to group them together in the help output.
E.g.
...
app.Commands = []cli.Command{
{
Name: "noop",
},
{
Name: "add",
Category: "template",
},
{
Name: "remove",
Category: "template",
},
}
...
Will include:
...
COMMANDS:
noop
Template actions:
add
remove
...
Exit code
Calling App.Run
will not automatically call os.Exit
, which means that by
default the exit code will "fall through" to being 0
. An explicit exit code
may be set by returning a non-nil error that fulfills cli.ExitCoder
, or a
cli.MultiError
that includes an error that fulfills cli.ExitCoder
, e.g.:
package main
import (
"os"
"github.com/codegangsta/cli"
)
func main() {
app := cli.NewApp()
app.Flags = []cli.Flag{
cli.BoolTFlag{
Name: "ginger-crouton",
Usage: "is it in the soup?",
},
}
app.Action = func(ctx *cli.Context) error {
if !ctx.Bool("ginger-crouton") {
return cli.NewExitError("it is not in the soup", 86)
}
return nil
}
app.Run(os.Args)
}
Bash Completion
You can enable completion commands by setting the EnableBashCompletion
flag on the App
object. By default, this setting will only auto-complete to
show an app's subcommands, but you can write your own completion methods for
the App or its subcommands.
...
var tasks = []string{"cook", "clean", "laundry", "eat", "sleep", "code"}
app := cli.NewApp()
app.EnableBashCompletion = true
app.Commands = []cli.Command{
{
Name: "complete",
Aliases: []string{"c"},
Usage: "complete a task on the list",
Action: func(c *cli.Context) error {
fmt.Println("completed task: ", c.Args().First())
return nil
},
BashComplete: func(c *cli.Context) {
// This will complete if no args are passed
if c.NArg() > 0 {
return
}
for _, t := range tasks {
fmt.Println(t)
}
},
}
}
...
To Enable
Source the autocomplete/bash_autocomplete
file in your .bashrc
file while
setting the PROG
variable to the name of your program:
PROG=myprogram source /.../cli/autocomplete/bash_autocomplete
To Distribute
Copy autocomplete/bash_autocomplete
into /etc/bash_completion.d/
and rename
it to the name of the program you wish to add autocomplete support for (or
automatically install it there if you are distributing a package). Don't forget
to source the file to make it active in the current shell.
sudo cp src/bash_autocomplete /etc/bash_completion.d/<myprogram>
source /etc/bash_completion.d/<myprogram>
Alternatively, you can just document that users should source the generic
autocomplete/bash_autocomplete
in their bash configuration with $PROG
set
to the name of their program (as above).
Generated Help Text Customization
All of the help text generation may be customized, and at multiple levels. The
templates are exposed as variables AppHelpTemplate
, CommandHelpTemplate
, and
SubcommandHelpTemplate
which may be reassigned or augmented, and full override
is possible by assigning a compatible func to the cli.HelpPrinter
variable,
e.g.:
package main
import (
"fmt"
"io"
"os"
"github.com/codegangsta/cli"
)
func main() {
// EXAMPLE: Append to an existing template
cli.AppHelpTemplate = fmt.Sprintf(`%s
WEBSITE: http://awesometown.example.com
SUPPORT: support@awesometown.example.com
`, cli.AppHelpTemplate)
// EXAMPLE: Override a template
cli.AppHelpTemplate = `NAME:
{{.Name}} - {{.Usage}}
USAGE:
{{.HelpName}} {{if .VisibleFlags}}[global options]{{end}}{{if .Commands}} command
[command options]{{end}} {{if
.ArgsUsage}}{{.ArgsUsage}}{{else}}[arguments...]{{end}}
{{if len .Authors}}
AUTHOR(S):
{{range .Authors}}{{ . }}{{end}}
{{end}}{{if .Commands}}
COMMANDS:
{{range .Commands}}{{if not .HideHelp}} {{join .Names ", "}}{{ "\t"
}}{{.Usage}}{{ "\n" }}{{end}}{{end}}{{end}}{{if .VisibleFlags}}
GLOBAL OPTIONS:
{{range .VisibleFlags}}{{.}}
{{end}}{{end}}{{if .Copyright }}
COPYRIGHT:
{{.Copyright}}
{{end}}{{if .Version}}
VERSION:
{{.Version}}
{{end}}
`
// EXAMPLE: Replace the `HelpPrinter` func
cli.HelpPrinter = func(w io.Writer, templ string, data interface{}) {
fmt.Println("Ha HA. I pwnd the help!!1")
}
cli.NewApp().Run(os.Args)
}
Contribution Guidelines
Feel free to put up a pull request to fix a bug or maybe add a feature. I will give it a code review and make sure that it does not break backwards compatibility. If I or any other collaborators agree that it is in line with the vision of the project, we will work with you to get the code into a mergeable state and merge it into the master branch.
If you have contributed something significant to the project, I will most likely add you as a collaborator. As a collaborator you are given the ability to merge others pull requests. It is very important that new code does not break existing code, so be careful about what code you do choose to merge. If you have any questions feel free to link @codegangsta to the issue in question and we can review it together.
If you feel like you have contributed to the project but have not yet been added as a collaborator, I probably forgot to add you. Hit @codegangsta up over email and we will get it figured out.
Documentation ¶
Overview ¶
Package cli provides a minimal framework for creating and organizing command line Go applications. cli is designed to be easy to understand and write, the most simple cli application can be written as follows:
func main() { cli.NewApp().Run(os.Args) }
Of course this application does not do much, so let's make this an actual application:
func main() { app := cli.NewApp() app.Name = "greet" app.Usage = "say a greeting" app.Action = func(c *cli.Context) error { println("Greetings") } app.Run(os.Args) }
Index ¶
- Variables
- func DefaultAppComplete(c *Context)
- func HandleAction(action interface{}, context *Context) (err error)
- func HandleExitCoder(err error)
- func ShowAppHelp(c *Context)
- func ShowCommandCompletions(ctx *Context, command string)
- func ShowCommandHelp(ctx *Context, command string) error
- func ShowCompletions(c *Context)
- func ShowSubcommandHelp(c *Context) error
- func ShowVersion(c *Context)
- type ActionFunc
- type AfterFunc
- type App
- func (a *App) Categories() CommandCategories
- func (a *App) Command(name string) *Command
- func (a *App) Run(arguments []string) (err error)
- func (a *App) RunAndExitOnError()
- func (a *App) RunAsSubcommand(ctx *Context) (err error)
- func (a *App) Setup()
- func (a *App) VisibleCategories() []*CommandCategory
- func (a *App) VisibleCommands() []Command
- func (a *App) VisibleFlags() []Flag
- type Args
- type Author
- type BashCompleteFunc
- type BeforeFunc
- type BoolFlag
- type BoolTFlag
- type Command
- type CommandCategories
- type CommandCategory
- type CommandNotFoundFunc
- type Commands
- type Context
- func (c *Context) Args() Args
- func (c *Context) Bool(name string) bool
- func (c *Context) BoolT(name string) bool
- func (c *Context) Duration(name string) time.Duration
- func (c *Context) FlagNames() (names []string)
- func (c *Context) Float64(name string) float64
- func (c *Context) Generic(name string) interface{}
- func (c *Context) GlobalBool(name string) bool
- func (c *Context) GlobalBoolT(name string) bool
- func (c *Context) GlobalDuration(name string) time.Duration
- func (c *Context) GlobalFlagNames() (names []string)
- func (c *Context) GlobalFloat64(name string) float64
- func (c *Context) GlobalGeneric(name string) interface{}
- func (c *Context) GlobalInt(name string) int
- func (c *Context) GlobalIntSlice(name string) []int
- func (c *Context) GlobalIsSet(name string) bool
- func (c *Context) GlobalSet(name, value string) error
- func (c *Context) GlobalString(name string) string
- func (c *Context) GlobalStringSlice(name string) []string
- func (c *Context) Int(name string) int
- func (c *Context) IntSlice(name string) []int
- func (c *Context) IsSet(name string) bool
- func (c *Context) NArg() int
- func (c *Context) NumFlags() int
- func (c *Context) Parent() *Context
- func (c *Context) Set(name, value string) error
- func (c *Context) String(name string) string
- func (c *Context) StringSlice(name string) []string
- type DurationFlag
- type ExitCoder
- type ExitError
- type Flag
- type FlagStringFunc
- type Float64Flag
- type Generic
- type GenericFlag
- type IntFlag
- type IntSlice
- type IntSliceFlag
- type MultiError
- type OnUsageErrorFunc
- type StringFlag
- type StringSlice
- type StringSliceFlag
Constants ¶
This section is empty.
Variables ¶
var AppHelpTemplate = `` /* 768-byte string literal not displayed */
AppHelpTemplate is the text template for the Default help topic. cli.go uses text/template to render templates. You can render custom help text by setting this variable.
var BashCompletionFlag = BoolFlag{ Name: "generate-bash-completion", Hidden: true, }
BashCompletionFlag enables bash-completion for all commands and subcommands
var CommandHelpTemplate = `` /* 358-byte string literal not displayed */
CommandHelpTemplate is the text template for the command help topic. cli.go uses text/template to render templates. You can render custom help text by setting this variable.
var ErrWriter io.Writer = os.Stderr
ErrWriter is used to write errors to the user. This can be anything implementing the io.Writer interface and defaults to os.Stderr.
var HelpFlag = BoolFlag{
Name: "help, h",
Usage: "show help",
}
HelpFlag prints the help for all commands and subcommands Set to the zero value (BoolFlag{}) to disable flag -- keeps subcommand unless HideHelp is set to true)
var HelpPrinter helpPrinter = printHelp
HelpPrinter is a function that writes the help output. If not set a default is used. The function signature is: func(w io.Writer, templ string, data interface{})
var OsExiter = os.Exit
OsExiter is the function used when the app exits. If not set defaults to os.Exit.
var SubcommandHelpTemplate = `` /* 433-byte string literal not displayed */
SubcommandHelpTemplate is the text template for the subcommand help topic. cli.go uses text/template to render templates. You can render custom help text by setting this variable.
var VersionFlag = BoolFlag{
Name: "version, v",
Usage: "print the version",
}
VersionFlag prints the version for the application
var VersionPrinter = printVersion
VersionPrinter prints the version for the App
Functions ¶
func DefaultAppComplete ¶
func DefaultAppComplete(c *Context)
DefaultAppComplete prints the list of subcommands as the default app completion method
func HandleAction ¶
HandleAction uses ✧✧✧reflection✧✧✧ to figure out if the given Action is an ActionFunc, a func with the legacy signature for Action, or some other invalid thing. If it's an ActionFunc or a func with the legacy signature for Action, the func is run!
func HandleExitCoder ¶
func HandleExitCoder(err error)
HandleExitCoder checks if the error fulfills the ExitCoder interface, and if so prints the error to stderr (if it is non-empty) and calls OsExiter with the given exit code. If the given error is a MultiError, then this func is called on all members of the Errors slice.
func ShowCommandCompletions ¶
ShowCommandCompletions prints the custom completions for a given command
func ShowCommandHelp ¶
ShowCommandHelp prints help for the given command
func ShowCompletions ¶
func ShowCompletions(c *Context)
ShowCompletions prints the lists of commands within a given context
func ShowSubcommandHelp ¶
ShowSubcommandHelp prints help for the given subcommand
Types ¶
type ActionFunc ¶
ActionFunc is the action to execute when no subcommands are specified
type AfterFunc ¶
AfterFunc is an action to execute after any subcommands are run, but after the subcommand has finished it is run even if Action() panics
type App ¶
type App struct { // The name of the program. Defaults to path.Base(os.Args[0]) Name string // Full name of command for help, defaults to Name HelpName string // Description of the program. Usage string // Text to override the USAGE section of help UsageText string // Description of the program argument format. ArgsUsage string // Version of the program Version string // List of commands to execute Commands []Command // List of flags to parse Flags []Flag // Boolean to enable bash completion commands EnableBashCompletion bool // Boolean to hide built-in help command HideHelp bool // Boolean to hide built-in version flag and the VERSION section of help HideVersion bool // An action to execute when the bash-completion flag is set BashComplete BashCompleteFunc // An action to execute before any subcommands are run, but after the context is ready // If a non-nil error is returned, no subcommands are run Before BeforeFunc // An action to execute after any subcommands are run, but after the subcommand has finished // It is run even if Action() panics After AfterFunc // The action to execute when no subcommands are specified Action interface{} // Execute this function if the proper command cannot be found CommandNotFound CommandNotFoundFunc // Execute this function if an usage error occurs OnUsageError OnUsageErrorFunc // Compilation date Compiled time.Time // List of all authors who contributed Authors []Author // Copyright of the binary if any Copyright string // Name of Author (Note: Use App.Authors, this is deprecated) Author string // Email of Author (Note: Use App.Authors, this is deprecated) Email string // Writer writer to write output to Writer io.Writer // ErrWriter writes error output ErrWriter io.Writer // Other custom info Metadata map[string]interface{} // contains filtered or unexported fields }
App is the main structure of a cli application. It is recommended that an app be created with the cli.NewApp() function
func NewApp ¶
func NewApp() *App
NewApp creates a new cli Application with some reasonable defaults for Name, Usage, Version and Action.
func (*App) Categories ¶
func (a *App) Categories() CommandCategories
Categories returns a slice containing all the categories with the commands they contain
func (*App) Command ¶
Command returns the named command on App. Returns nil if the command does not exist
func (*App) Run ¶
Run is the entry point to the cli app. Parses the arguments slice and routes to the proper flag/args combination
func (*App) RunAndExitOnError ¶
func (a *App) RunAndExitOnError()
DEPRECATED: Another entry point to the cli app, takes care of passing arguments and error handling
func (*App) RunAsSubcommand ¶
RunAsSubcommand invokes the subcommand given the context, parses ctx.Args() to generate command-specific flags
func (*App) Setup ¶
func (a *App) Setup()
Setup runs initialization code to ensure all data structures are ready for `Run` or inspection prior to `Run`. It is internally called by `Run`, but will return early if setup has already happened.
func (*App) VisibleCategories ¶
func (a *App) VisibleCategories() []*CommandCategory
VisibleCategories returns a slice of categories and commands that are Hidden=false
func (*App) VisibleCommands ¶
VisibleCommands returns a slice of the Commands with Hidden=false
func (*App) VisibleFlags ¶
VisibleFlags returns a slice of the Flags with Hidden=false
type Args ¶
type Args []string
Args contains apps console arguments
type BashCompleteFunc ¶
type BashCompleteFunc func(*Context)
BashCompleteFunc is an action to execute when the bash-completion flag is set
type BeforeFunc ¶
BeforeFunc is an action to execute before any subcommands are run, but after the context is ready if a non-nil error is returned, no subcommands are run
type BoolFlag ¶
BoolFlag is a switch that defaults to false
type BoolTFlag ¶
BoolTFlag this represents a boolean flag that is true by default, but can still be set to false by --some-flag=false
type Command ¶
type Command struct { // The name of the command Name string // short name of the command. Typically one character (deprecated, use `Aliases`) ShortName string // A list of aliases for the command Aliases []string // A short description of the usage of this command Usage string // Custom text to show on USAGE section of help UsageText string // A longer explanation of how the command works Description string // A short description of the arguments of this command ArgsUsage string // The category the command is part of Category string // The function to call when checking for bash command completions BashComplete BashCompleteFunc // An action to execute before any sub-subcommands are run, but after the context is ready // If a non-nil error is returned, no sub-subcommands are run Before BeforeFunc // An action to execute after any subcommands are run, but after the subcommand has finished // It is run even if Action() panics After AfterFunc // The function to call when this command is invoked Action interface{} // Execute this function if a usage error occurs. OnUsageError OnUsageErrorFunc // List of child commands Subcommands Commands // List of flags to parse Flags []Flag // Treat all flags as normal arguments if true SkipFlagParsing bool // Boolean to hide built-in help command HideHelp bool // Boolean to hide this command from help or completion Hidden bool // Full name of command for help, defaults to full command name, including parent commands. HelpName string // contains filtered or unexported fields }
Command is a subcommand for a cli.App.
func (Command) FullName ¶
FullName returns the full name of the command. For subcommands this ensures that parent commands are part of the command path
func (Command) HasName ¶
HasName returns true if Command.Name or Command.ShortName matches given name
func (Command) Run ¶
Run invokes the command given the context, parses ctx.Args() to generate command-specific flags
func (Command) VisibleFlags ¶
VisibleFlags returns a slice of the Flags with Hidden=false
type CommandCategories ¶
type CommandCategories []*CommandCategory
CommandCategories is a slice of *CommandCategory.
func (CommandCategories) AddCommand ¶
func (c CommandCategories) AddCommand(category string, command Command) CommandCategories
AddCommand adds a command to a category.
func (CommandCategories) Len ¶
func (c CommandCategories) Len() int
func (CommandCategories) Less ¶
func (c CommandCategories) Less(i, j int) bool
func (CommandCategories) Swap ¶
func (c CommandCategories) Swap(i, j int)
type CommandCategory ¶
CommandCategory is a category containing commands.
func (*CommandCategory) VisibleCommands ¶
func (c *CommandCategory) VisibleCommands() []Command
VisibleCommands returns a slice of the Commands with Hidden=false
type CommandNotFoundFunc ¶
CommandNotFoundFunc is executed if the proper command cannot be found
type Context ¶
Context is a type that is passed through to each Handler action in a cli application. Context can be used to retrieve context-specific Args and parsed command-line options.
func NewContext ¶
NewContext creates a new context. For use in when invoking an App or Command action.
func (*Context) Bool ¶
Bool looks up the value of a local bool flag, returns false if no bool flag exists
func (*Context) BoolT ¶
BoolT looks up the value of a local boolT flag, returns false if no bool flag exists
func (*Context) Duration ¶
Duration looks up the value of a local time.Duration flag, returns 0 if no time.Duration flag exists
func (*Context) Float64 ¶
Float64 looks up the value of a local float64 flag, returns 0 if no float64 flag exists
func (*Context) Generic ¶
Generic looks up the value of a local generic flag, returns nil if no generic flag exists
func (*Context) GlobalBool ¶
GlobalBool looks up the value of a global bool flag, returns false if no bool flag exists
func (*Context) GlobalBoolT ¶
GlobalBoolT looks up the value of a global bool flag, returns true if no bool flag exists
func (*Context) GlobalDuration ¶
GlobalDuration looks up the value of a global time.Duration flag, returns 0 if no time.Duration flag exists
func (*Context) GlobalFlagNames ¶
GlobalFlagNames returns a slice of global flag names used by the app.
func (*Context) GlobalFloat64 ¶
GlobalFloat64 looks up the value of a global float64 flag, returns float64(0) if no float64 flag exists
func (*Context) GlobalGeneric ¶
GlobalGeneric looks up the value of a global generic flag, returns nil if no generic flag exists
func (*Context) GlobalInt ¶
GlobalInt looks up the value of a global int flag, returns 0 if no int flag exists
func (*Context) GlobalIntSlice ¶
GlobalIntSlice looks up the value of a global int slice flag, returns nil if no int slice flag exists
func (*Context) GlobalIsSet ¶
GlobalIsSet determines if the global flag was actually set
func (*Context) GlobalString ¶
GlobalString looks up the value of a global string flag, returns "" if no string flag exists
func (*Context) GlobalStringSlice ¶
GlobalStringSlice looks up the value of a global string slice flag, returns nil if no string slice flag exists
func (*Context) IntSlice ¶
IntSlice looks up the value of a local int slice flag, returns nil if no int slice flag exists
func (*Context) String ¶
String looks up the value of a local string flag, returns "" if no string flag exists
func (*Context) StringSlice ¶
StringSlice looks up the value of a local string slice flag, returns nil if no string slice flag exists
type DurationFlag ¶
type DurationFlag struct { Name string Value time.Duration Usage string EnvVar string Destination *time.Duration Hidden bool }
DurationFlag is a flag that takes a duration specified in Go's duration format: https://golang.org/pkg/time/#ParseDuration
func (DurationFlag) Apply ¶
func (f DurationFlag) Apply(set *flag.FlagSet)
Apply populates the flag given the flag set and environment
func (DurationFlag) GetName ¶
func (f DurationFlag) GetName() string
GetName returns the name of the flag.
func (DurationFlag) String ¶
func (f DurationFlag) String() string
String returns a readable representation of this value (for usage defaults)
type ExitError ¶
type ExitError struct {
// contains filtered or unexported fields
}
ExitError fulfills both the builtin `error` interface and `ExitCoder`
func NewExitError ¶
NewExitError makes a new *ExitError
type Flag ¶
type Flag interface { fmt.Stringer // Apply Flag settings to the given flag set Apply(*flag.FlagSet) GetName() string }
Flag is a common interface related to parsing flags in cli. For more advanced flag parsing techniques, it is recommended that this interface be implemented.
type FlagStringFunc ¶
FlagStringFunc is used by the help generation to display a flag, which is expected to be a single line.
var FlagStringer FlagStringFunc = stringifyFlag
FlagStringer converts a flag definition to a string. This is used by help to display a flag.
type Float64Flag ¶
type Float64Flag struct { Name string Value float64 Usage string EnvVar string Destination *float64 Hidden bool }
Float64Flag is a flag that takes an float value Errors if the value provided cannot be parsed
func (Float64Flag) Apply ¶
func (f Float64Flag) Apply(set *flag.FlagSet)
Apply populates the flag given the flag set and environment
func (Float64Flag) GetName ¶
func (f Float64Flag) GetName() string
GetName returns the name of the flag.
type GenericFlag ¶
GenericFlag is the flag type for types implementing Generic
func (GenericFlag) Apply ¶
func (f GenericFlag) Apply(set *flag.FlagSet)
Apply takes the flagset and calls Set on the generic flag with the value provided by the user for parsing by the flag
func (GenericFlag) GetName ¶
func (f GenericFlag) GetName() string
GetName returns the name of a flag.
func (GenericFlag) String ¶
func (f GenericFlag) String() string
String returns the string representation of the generic flag to display the help text to the user (uses the String() method of the generic flag to show the value)
type IntFlag ¶
type IntFlag struct { Name string Value int Usage string EnvVar string Destination *int Hidden bool }
IntFlag is a flag that takes an integer Errors if the value provided cannot be parsed
type IntSlice ¶
type IntSlice []int
IntSlice is an opaque type for []int to satisfy flag.Value
type IntSliceFlag ¶
IntSliceFlag is an int flag that can be specified multiple times on the command-line
func (IntSliceFlag) Apply ¶
func (f IntSliceFlag) Apply(set *flag.FlagSet)
Apply populates the flag given the flag set and environment
func (IntSliceFlag) GetName ¶
func (f IntSliceFlag) GetName() string
GetName returns the name of the flag.
type MultiError ¶
type MultiError struct {
Errors []error
}
MultiError is an error that wraps multiple errors.
func NewMultiError ¶
func NewMultiError(err ...error) MultiError
NewMultiError creates a new MultiError. Pass in one or more errors.
type OnUsageErrorFunc ¶
OnUsageErrorFunc is executed if an usage error occurs. This is useful for displaying customized usage error messages. This function is able to replace the original error messages. If this function is not set, the "Incorrect usage" is displayed and the execution is interrupted.
type StringFlag ¶
type StringFlag struct { Name string Value string Usage string EnvVar string Destination *string Hidden bool }
StringFlag represents a flag that takes as string value
func (StringFlag) Apply ¶
func (f StringFlag) Apply(set *flag.FlagSet)
Apply populates the flag given the flag set and environment
func (StringFlag) GetName ¶
func (f StringFlag) GetName() string
GetName returns the name of the flag.
type StringSlice ¶
type StringSlice []string
StringSlice is an opaque type for []string to satisfy flag.Value
func (*StringSlice) Set ¶
func (f *StringSlice) Set(value string) error
Set appends the string value to the list of values
func (*StringSlice) String ¶
func (f *StringSlice) String() string
String returns a readable representation of this value (for usage defaults)
func (*StringSlice) Value ¶
func (f *StringSlice) Value() []string
Value returns the slice of strings set by this flag
type StringSliceFlag ¶
type StringSliceFlag struct { Name string Value *StringSlice Usage string EnvVar string Hidden bool }
StringSliceFlag is a string flag that can be specified multiple times on the command-line
func (StringSliceFlag) Apply ¶
func (f StringSliceFlag) Apply(set *flag.FlagSet)
Apply populates the flag given the flag set and environment
func (StringSliceFlag) GetName ¶
func (f StringSliceFlag) GetName() string
GetName returns the name of a flag.