cli

Documentation

Overview

Package cli contains utilities for "Command Line Interface" applications.

Index

• func ReadPipedInput(maxLength int) ([]byte, error)
• func ReadSecure(prompt string) ([]byte, error)
• func SetupCommandParams(c *cobra.Command, params []Param) error
• func SignalsHandler(list []os.Signal) chan os.Signal
• type Param
• type Spinner
  • func NewSpinner(opts ...SpinnerOption) *Spinner
  • func (s *Spinner) Start()
  • func (s *Spinner) Stop()
• type SpinnerOption
  • func WithSpinnerColor(color string) SpinnerOption

Examples

• ReadPipedInput
• ReadSecure
• SetupCommandParams
• SignalsHandler

Functions

func ReadPipedInput

func ReadPipedInput(maxLength int) ([]byte, error)

ReadPipedInput retrieves contents passed-in from standard input up to the provided maximum number of bytes.

Example

// Read a maximum of 32 bytes from standard input
input, err := ReadPipedInput(32)
if len(input) > 0 && err != nil {
	// Handle error
	panic(err)
}
log.Printf("data received: %s", input)

func ReadSecure

func ReadSecure(prompt string) ([]byte, error)

ReadSecure will interactively prompt the user to enter a value. The value provided won't be displayed on the screen.

Example

// Interactively prompt the user to enter a value. The value provided won't be
// displayed on the screen.
password, err := ReadSecure("Enter your password: ")
if err != nil {
	// Handle error
	panic(err)
}
log.Printf("you entered: %s", password)

func SetupCommandParams

func SetupCommandParams(c *cobra.Command, params []Param) error

SetupCommandParams will properly configure the command with the provided parameter list.

Example

Register a list of parameters to a sample command.

sampleCmd := &cobra.Command{}
parameters := []Param{
	{
		Name:      "name-of-parameter",
		Usage:     "describe the parameter use or intent",
		FlagKey:   "cmd.parameter.name",
		ByDefault: 9090,
	},
	{
		Name:      "bool-flag",
		Usage:     "parameters support several basic types",
		FlagKey:   "cmd.parameter.flag",
		ByDefault: false,
	},
}
if err := SetupCommandParams(sampleCmd, parameters); err != nil {
	panic(err)
}

func SignalsHandler

func SignalsHandler(list []os.Signal) chan os.Signal

SignalsHandler returns a properly configured OS signals handler channel.

Example

// Register the signals to look for and wait for one
s := <-SignalsHandler([]os.Signal{
	syscall.SIGHUP,
	syscall.SIGINT,
	syscall.SIGTERM,
	syscall.SIGQUIT,
})
log.Printf("signal received: %s", s)

Types

type Param

type Param struct {
	// Name of the parameter, will be displayed to the user when inspecting the
	// help information for the command.
	Name string

	// Brief and clear description of the parameter usage or intent, will be
	// displayed to the user when inspecting the help information for the command.
	Usage string

	// Internal code for the parameter. This should match the structure of a
	// configuration file when used and can be useful to add 'namespaces' for
	// configuration settings. This key should be used when reading configuration
	// options using viper. For example:
	//   root.child.parameter
	FlagKey string

	// Default value to use for the parameter, the type of the default value will
	// determine the expected type for the parameter. Supported types are:
	// int, int32, int64 uint32, uint64, string, bool, []string
	ByDefault interface{}

	// If provided the parameter can be provided using a shorthand letter that can
	// be used after a single dash. Must be unique.
	Short string

	// Parameters are optional by default. If instead you wish your command to report
	// an error when a parameter has not been set, mark it as required.
	Required bool
}

Param represents an individual CLI parameter.

type Spinner

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

Spinner indicator.

func NewSpinner

func NewSpinner(opts ...SpinnerOption) *Spinner

NewSpinner creates a new spinner indicator instance.

func (*Spinner) Start

func (s *Spinner) Start()

Start the spinner indicator.

func (*Spinner) Stop

func (s *Spinner) Stop()

Stop the spinner indicator.

type SpinnerOption

type SpinnerOption = func(s *Spinner)

SpinnerOption provide a functional style mechanism to adjust the settings when creating a new spinner instance.

func WithSpinnerColor

func WithSpinnerColor(color string) SpinnerOption

WithSpinnerColor adjust the color used for the spinner indicator. Supported values are: "green", "blue", "yellow" and "red".