cli

package
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 Go to latest Published: Jan 3, 2018 License: GPL-3.0, MIT Imports: 15 Imported by: 0

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

Constants

This section is empty.

Variables

View Source 
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.

View Source 
var BashCompletionFlag = BoolFlag{
	Name:   "generate-bash-completion",
	Hidden: true,
}

BashCompletionFlag enables bash-completion for all commands and subcommands

View Source 
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.

View Source 
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.

View Source 
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)

View Source 
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{})

View Source 
var OsExiter = os.Exit

OsExiter is the function used when the app exits. If not set defaults to os.Exit.

View Source 
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.

View Source 
var VersionFlag = BoolFlag{
	Name:  "version, v",
	Usage: "print the version",
}

VersionFlag prints the version for the application

View Source 
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 

func HandleAction(action interface{}, context *Context) (err error)

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 ShowAppHelp 

func ShowAppHelp(c *Context)

ShowAppHelp is an action that displays the help.

func ShowCommandCompletions 

func ShowCommandCompletions(ctx *Context, command string)

ShowCommandCompletions prints the custom completions for a given command

func ShowCommandHelp 

func ShowCommandHelp(ctx *Context, command string) error

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 

func ShowSubcommandHelp(c *Context) error

ShowSubcommandHelp prints help for the given subcommand

func ShowVersion 

func ShowVersion(c *Context)

ShowVersion prints the version number of the App

Types

type ActionFunc 

type ActionFunc func(*Context) error

ActionFunc is the action to execute when no subcommands are specified

type AfterFunc 

type AfterFunc func(*Context) error

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 

func (a *App) Command(name string) *Command

Command returns the named command on App. Returns nil if the command does not exist

func (*App) Run 

func (a *App) Run(arguments []string) (err error)

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 

func (a *App) RunAsSubcommand(ctx *Context) (err error)

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 

func (a *App) VisibleCommands() []Command

VisibleCommands returns a slice of the Commands with Hidden=false

func (*App) VisibleFlags 

func (a *App) VisibleFlags() []Flag

VisibleFlags returns a slice of the Flags with Hidden=false

type Args 

type Args []string

Args contains apps console arguments

func (Args) First 

func (a Args) First() string

First returns the first argument, or else a blank string

func (Args) Get 

func (a Args) Get(n int) string

Get returns the nth argument, or else a blank string

func (Args) Present 

func (a Args) Present() bool

Present checks if there are any arguments present

func (Args) Swap 

func (a Args) Swap(from, to int) error

Swap swaps arguments at the given indexes

func (Args) Tail 

func (a Args) Tail() []string

Tail returns the rest of the arguments (not the first one) or else an empty string slice

type Author 

type Author struct {
	Name  string // The Authors name
	Email string // The Authors email
}

Author represents someone who has contributed to a cli project.

func (Author) String 

func (a Author) String() string

String makes Author comply to the Stringer interface, to allow an easy print in the templating process

type BashCompleteFunc 

type BashCompleteFunc func(*Context)

BashCompleteFunc is an action to execute when the bash-completion flag is set

type BeforeFunc 

type BeforeFunc func(*Context) error

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 

type BoolFlag struct {
	Name        string
	Usage       string
	EnvVar      string
	Destination *bool
	Hidden      bool
}

BoolFlag is a switch that defaults to false

func (BoolFlag) Apply 

func (f BoolFlag) Apply(set *flag.FlagSet)

Apply populates the flag given the flag set and environment

func (BoolFlag) GetName 

func (f BoolFlag) GetName() string

GetName returns the name of the flag.

func (BoolFlag) String 

func (f BoolFlag) String() string

String returns a readable representation of this value (for usage defaults)

type BoolTFlag 

type BoolTFlag struct {
	Name        string
	Usage       string
	EnvVar      string
	Destination *bool
	Hidden      bool
}

BoolTFlag this represents a boolean flag that is true by default, but can still be set to false by --some-flag=false

func (BoolTFlag) Apply 

func (f BoolTFlag) Apply(set *flag.FlagSet)

Apply populates the flag given the flag set and environment

func (BoolTFlag) GetName 

func (f BoolTFlag) GetName() string

GetName returns the name of the flag.

func (BoolTFlag) String 

func (f BoolTFlag) String() string

String returns a readable representation of this value (for usage defaults)

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 

func (c Command) FullName() string

FullName returns the full name of the command. For subcommands this ensures that parent commands are part of the command path

func (Command) HasName 

func (c Command) HasName(name string) bool

HasName returns true if Command.Name or Command.ShortName matches given name

func (Command) Names 

func (c Command) Names() []string

Names returns the names including short names and aliases.

func (Command) Run 

func (c Command) Run(ctx *Context) (err error)

Run invokes the command given the context, parses ctx.Args() to generate command-specific flags

func (Command) VisibleFlags 

func (c Command) VisibleFlags() []Flag

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 

type CommandCategory struct {
	Name     string
	Commands Commands
}

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 

type CommandNotFoundFunc func(*Context, string)

CommandNotFoundFunc is executed if the proper command cannot be found

type Commands 

type Commands []Command

Commands is a slice of Command

type Context 

type Context struct {
	App     *App
	Command Command
	// contains filtered or unexported fields
}

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 

func NewContext(app *App, set *flag.FlagSet, parentCtx *Context) *Context

NewContext creates a new context. For use in when invoking an App or Command action.

func (*Context) Args 

func (c *Context) Args() Args

Args returns the command line arguments associated with the context.

func (*Context) Bool 

func (c *Context) Bool(name string) bool

Bool looks up the value of a local bool flag, returns false if no bool flag exists

func (*Context) BoolT 

func (c *Context) BoolT(name string) bool

BoolT looks up the value of a local boolT flag, returns false if no bool flag exists

func (*Context) Duration 

func (c *Context) Duration(name string) time.Duration

Duration looks up the value of a local time.Duration flag, returns 0 if no time.Duration flag exists

func (*Context) FlagNames 

func (c *Context) FlagNames() (names []string)

FlagNames returns a slice of flag names used in this context.

func (*Context) Float64 

func (c *Context) Float64(name string) float64

Float64 looks up the value of a local float64 flag, returns 0 if no float64 flag exists

func (*Context) Generic 

func (c *Context) Generic(name string) interface{}

Generic looks up the value of a local generic flag, returns nil if no generic flag exists

func (*Context) GlobalBool 

func (c *Context) GlobalBool(name string) bool

GlobalBool looks up the value of a global bool flag, returns false if no bool flag exists

func (*Context) GlobalBoolT 

func (c *Context) GlobalBoolT(name string) bool

GlobalBoolT looks up the value of a global bool flag, returns true if no bool flag exists

func (*Context) GlobalDuration 

func (c *Context) GlobalDuration(name string) time.Duration

GlobalDuration looks up the value of a global time.Duration flag, returns 0 if no time.Duration flag exists

func (*Context) GlobalFlagNames 

func (c *Context) GlobalFlagNames() (names []string)

GlobalFlagNames returns a slice of global flag names used by the app.

func (*Context) GlobalFloat64 

func (c *Context) GlobalFloat64(name string) float64

GlobalFloat64 looks up the value of a global float64 flag, returns float64(0) if no float64 flag exists

func (*Context) GlobalGeneric 

func (c *Context) GlobalGeneric(name string) interface{}

GlobalGeneric looks up the value of a global generic flag, returns nil if no generic flag exists

func (*Context) GlobalInt 

func (c *Context) GlobalInt(name string) int

GlobalInt looks up the value of a global int flag, returns 0 if no int flag exists

func (*Context) GlobalIntSlice 

func (c *Context) GlobalIntSlice(name string) []int

GlobalIntSlice looks up the value of a global int slice flag, returns nil if no int slice flag exists

func (*Context) GlobalIsSet 

func (c *Context) GlobalIsSet(name string) bool

GlobalIsSet determines if the global flag was actually set

func (*Context) GlobalSet 

func (c *Context) GlobalSet(name, value string) error

GlobalSet sets a context flag to a value on the global flagset

func (*Context) GlobalString 

func (c *Context) GlobalString(name string) string

GlobalString looks up the value of a global string flag, returns "" if no string flag exists

func (*Context) GlobalStringSlice 

func (c *Context) GlobalStringSlice(name string) []string

GlobalStringSlice looks up the value of a global string slice flag, returns nil if no string slice flag exists

func (*Context) Int 

func (c *Context) Int(name string) int

Int looks up the value of a local int flag, returns 0 if no int flag exists

func (*Context) IntSlice 

func (c *Context) IntSlice(name string) []int

IntSlice looks up the value of a local int slice flag, returns nil if no int slice flag exists

func (*Context) IsSet 

func (c *Context) IsSet(name string) bool

IsSet determines if the flag was actually set

func (*Context) NArg 

func (c *Context) NArg() int

NArg returns the number of the command line arguments.

func (*Context) NumFlags 

func (c *Context) NumFlags() int

NumFlags returns the number of flags set

func (*Context) Parent 

func (c *Context) Parent() *Context

Parent returns the parent context, if any

func (*Context) Set 

func (c *Context) Set(name, value string) error

Set sets a context flag to a value.

func (*Context) String 

func (c *Context) String(name string) string

String looks up the value of a local string flag, returns "" if no string flag exists

func (*Context) StringSlice 

func (c *Context) StringSlice(name string) []string

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 ExitCoder 

type ExitCoder interface {
	error
	ExitCode() int
}

ExitCoder is the interface checked by `App` and `Command` for a custom exit code

type ExitError 

type ExitError struct {
	// contains filtered or unexported fields
}

ExitError fulfills both the builtin `error` interface and `ExitCoder`

func NewExitError 

func NewExitError(message string, exitCode int) *ExitError

NewExitError makes a new *ExitError

func (*ExitError) Error 

func (ee *ExitError) Error() string

Error returns the string message, fulfilling the interface required by `error`

func (*ExitError) ExitCode 

func (ee *ExitError) ExitCode() int

ExitCode returns the exit code, fulfilling the interface required by `ExitCoder`

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 

type FlagStringFunc func(Flag) string

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.

func (Float64Flag) String 

func (f Float64Flag) String() string

String returns the usage

type Generic 

type Generic interface {
	Set(value string) error
	String() string
}

Generic is a generic parseable type identified by a specific flag

type GenericFlag 

type GenericFlag struct {
	Name   string
	Value  Generic
	Usage  string
	EnvVar string
	Hidden bool
}

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

func (IntFlag) Apply 

func (f IntFlag) Apply(set *flag.FlagSet)

Apply populates the flag given the flag set and environment

func (IntFlag) GetName 

func (f IntFlag) GetName() string

GetName returns the name of the flag.

func (IntFlag) String 

func (f IntFlag) String() string

String returns the usage

type IntSlice 

type IntSlice []int

IntSlice is an opaque type for []int to satisfy flag.Value

func (*IntSlice) Set 

func (f *IntSlice) Set(value string) error

Set parses the value into an integer and appends it to the list of values

func (*IntSlice) String 

func (f *IntSlice) String() string

String returns a readable representation of this value (for usage defaults)

func (*IntSlice) Value 

func (f *IntSlice) Value() []int

Value returns the slice of ints set by this flag

type IntSliceFlag 

type IntSliceFlag struct {
	Name   string
	Value  *IntSlice
	Usage  string
	EnvVar string
	Hidden bool
}

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.

func (IntSliceFlag) String 

func (f IntSliceFlag) String() string

String returns the usage

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.

func (MultiError) Error 

func (m MultiError) Error() string

Error implents the error interface.

type OnUsageErrorFunc 

type OnUsageErrorFunc func(context *Context, err error, isSubcommand bool) error

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.

func (StringFlag) String 

func (f StringFlag) String() string

String returns the usage

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.

func (StringSliceFlag) String 

func (f StringSliceFlag) String() string

String returns the usage

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