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 ¶ added in v0.0.8
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 ¶ added in v0.0.8
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 ¶ added in v0.0.8
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 ¶ added in v0.0.8
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 ¶ added in v0.0.8
func (f IntSliceFlag) GetName() string
GetName returns the name of the flag.
type MultiError ¶ added in v0.0.8
type MultiError struct {
Errors []error
}
MultiError is an error that wraps multiple errors.
func NewMultiError ¶ added in v0.0.8
func NewMultiError(err ...error) MultiError
NewMultiError creates a new MultiError. Pass in one or more errors.
func (MultiError) Error ¶ added in v0.0.8
func (m MultiError) Error() string
Error implents the error interface.
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 ¶ added in v0.0.8
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 ¶ added in v0.0.8
func (f StringSliceFlag) GetName() string
GetName returns the name of a flag.