survey

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 Go to latest Published: Nov 8, 2018 License: MIT Imports: 14 Imported by: 0

README

Survey

Build Status GoDoc

A library for building interactive prompts.

package main

import (
    "fmt"
    "gopkg.in/AlecAivazis/survey.v1"
)

// the questions to ask
var qs = []*survey.Question{
    {
        Name:     "name",
        Prompt:   &survey.Input{Message: "What is your name?"},
        Validate: survey.Required,
        Transform: survey.Title,
    },
    {
        Name: "color",
        Prompt: &survey.Select{
            Message: "Choose a color:",
            Options: []string{"red", "blue", "green"},
            Default: "red",
        },
    },
    {
        Name: "age",
        Prompt:   &survey.Input{Message: "How old are you?"},
    },
}

func main() {
    // the answers will be written to this struct
    answers := struct {
        Name          string                  // survey will match the question and field names
        FavoriteColor string `survey:"color"` // or you can tag fields to match a specific name
        Age           int                     // if the types don't match exactly, survey will try to convert for you
    }{}

    // perform the questions
    err := survey.Ask(qs, &answers)
    if err != nil {
        fmt.Println(err.Error())
        return
    }

    fmt.Printf("%s chose %s.", answers.Name, answers.FavoriteColor)
}

Table of Contents

  1. Examples
  2. Prompts
    1. Input
    2. Password
    3. Confirm
    4. Select
    5. MultiSelect
    6. Editor
  3. Validation
    1. Built-in Validators
  4. Help Text
    1. Changing the input rune
  5. Custom Types
  6. Customizing Output
  7. Versioning
  8. Testing

Examples

Examples can be found in the examples/ directory. Run them to see basic behavior:

go get gopkg.in/AlecAivazis/survey.v1

cd $GOPATH/src/gopkg.in/AlecAivazis/survey.v1

go run examples/simple.go
go run examples/validation.go

Prompts

Input
name := ""
prompt := &survey.Input{
    Message: "ping",
}
survey.AskOne(prompt, &name, nil)
Password
password := ""
prompt := &survey.Password{
    Message: "Please type your password",
}
survey.AskOne(prompt, &password, nil)
Confirm
name := false
prompt := &survey.Confirm{
    Message: "Do you like pie?",
}
survey.AskOne(prompt, &name, nil)
Select
color := ""
prompt := &survey.Select{
    Message: "Choose a color:",
    Options: []string{"red", "blue", "green"},
}
survey.AskOne(prompt, &color, nil)

The user can filter for options by typing while the prompt is active. The user can also press esc to toggle the ability cycle through the options with the j and k keys to do down and up respectively.

By default, the select prompt is limited to showing 7 options at a time and will paginate lists of options longer than that. To increase, you can either change the global survey.PageSize, or set the PageSize field on the prompt:

prompt := &survey.Select{..., PageSize: 10}
MultiSelect
days := []string{}
prompt := &survey.MultiSelect{
    Message: "What days do you prefer:",
    Options: []string{"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"},
}
survey.AskOne(prompt, &days, nil)

The user can filter for options by typing while the prompt is active. The user can also press esc to toggle the ability cycle through the options with the j and k keys to do down and up respectively.

By default, the MultiSelect prompt is limited to showing 7 options at a time and will paginate lists of options longer than that. To increase, you can either change the global survey.PageSize, or set the PageSize field on the prompt:

prompt := &survey.MultiSelect{..., PageSize: 10}
Editor

Launches the user's preferred editor (defined by the $EDITOR environment variable) on a temporary file. Once the user exits their editor, the contents of the temporary file are read in as the result. If neither of those are present, notepad (on Windows) or vim (Linux or Mac) is used.

Validation

Validating individual responses for a particular question can be done by defining a Validate field on the survey.Question to be validated. This function takes an interface{} type and returns an error to show to the user, prompting them for another response:

q := &survey.Question{
    Prompt: &survey.Input{Message: "Hello world validation"},
    Validate: func (val interface{}) error {
        // since we are validating an Input, the assertion will always succeed
        if str, ok := val.(string) ; !ok || len(str) > 10 {
            return errors.New("This response cannot be longer than 10 characters.")
        }
    }
}
Built-in Validators

survey comes prepackaged with a few validators to fit common situations. Currently these validators include:

name valid types description notes
Required any Rejects zero values of the response type Boolean values pass straight through since the zero value (false) is a valid response
MinLength(n) string Enforces that a response is at least the given length
MaxLength(n) string Enforces that a response is no longer than the given length

Help Text

All of the prompts have a Help field which can be defined to provide more information to your users:

&survey.Input{
    Message: "What is your phone number:",
    Help:    "Phone number should include the area code",
}
Changing the input rune

In some situations, ? is a perfectly valid response. To handle this, you can change the rune that survey looks for by setting the HelpInputRune variable in survey/core:

import (
    "gopkg.in/AlecAivazis/survey.v1"
    surveyCore "gopkg.in/AlecAivazis/survey.v1/core"
)

number := ""
prompt := &survey.Input{
    Message: "If you have this need, please give me a reasonable message.",
    Help:    "I couldn't come up with one.",
}

surveyCore.HelpIcon = '^'

survey.AskOne(prompt, &number, nil)

Custom Types

survey will assign prompt answers to your custom types if they implement this interface:

type settable interface {
    WriteAnswer(field string, value interface{}) error
}

Here is an example how to use them:

type MyValue struct {
    value string
}
func (my *MyValue) WriteAnswer(name string, value interface{}) error {
     my.value = value.(string)
}

myval := MyValue{}
survey.AskOne(
    &survey.Input{
        Message: "Enter something:",
    },
    &myval,
    nil,
)

Customizing Output

Customizing the icons and various parts of survey can easily be done by setting the following variables in survey/core:

name default description
ErrorIcon ✘ Before an error
HelpIcon ⓘ Before help text
QuestionIcon ? Before the message of a prompt
SelectFocusIcon ❯ Marks the current focus in Select and MultiSelect prompts
MarkedOptionIcon ◉ Marks a chosen selection in a MultiSelect prompt
UnmarkedOptionIcon ◯ Marks an unselected option in a MultiSelect prompt

Versioning

This project tries to maintain semantic GitHub releases as closely as possible and relies on gopkg.in to maintain those releases. Importing version 1 of survey would look like:

package main

import "gopkg.in/AlecAivazis/survey.v1"

Testing

You can test your program's interactive prompts using go-expect. The library can be used to expect a match on stdout and respond on stdin. Since os.Stdout in a go test process is not a TTY, if you are manipulating the cursor or using survey, you will need a way to interpret terminal / ANSI escape sequences for things like CursorLocation. vt10x.NewVT10XConsole will create a go-expect console that also multiplexes stdio to an in-memory virtual terminal.

For example, you can test a binary utilizing survey by connecting the Console's tty to a subprocess's stdio.

func TestCLI(t *testing.T) {
 	// Multiplex stdin/stdout to a virtual terminal to respond to ANSI escape
 	// sequences (i.e. cursor position report).
 	c, state, err := vt10x.NewVT10XConsole()
	require.Nil(t, err)
	defer c.Close()

	donec := make(chan struct{})
	go func() {
		defer close(donec)
    		c.ExpectString("What is your name?")
    		c.SendLine("Johnny Appleseed")
    		c.ExpectEOF()
  	}()

	cmd := exec.Command("your-cli")
  	cmd.Stdin = c.Tty()
  	cmd.Stdout = c.Tty()
  	cmd.Stderr = c.Tty()

  	err = cmd.Run()
  	require.Nil(t, err)

  	// Close the slave end of the pty, and read the remaining bytes from the master end.
  	c.Tty().Close()
  	<-donec

  	// Dump the terminal's screen.
  	t.Log(expect.StripTrailingEmptyLines(state.String()))
}

If your application is decoupled from os.Stdout and os.Stdin, you can even test through the tty alone. survey itself is tested in this manner.

func TestCLI(t *testing.T) {
  	// Multiplex stdin/stdout to a virtual terminal to respond to ANSI escape
  	// sequences (i.e. cursor position report).
	c, state, err := vt10x.NewVT10XConsole()
	require.Nil(t, err)
  	defer c.Close()

  	donec := make(chan struct{})
	go func() {
    		defer close(donec)
    		c.ExpectString("What is your name?")
    		c.SendLine("Johnny Appleseed")
    		c.ExpectEOF()
	}()

  	prompt := &Input{
    		Message: "What is your name?",
  	}
  	prompt.WithStdio(Stdio(c))

  	answer, err := prompt.Prompt()
  	require.Nil(t, err)
  	require.Equal(t, "Johnny Appleseed", answer)

  	// Close the slave end of the pty, and read the remaining bytes from the master end.
  	c.Tty().Close()
  	<-donec

  	// Dump the terminal's screen.
  	t.Log(expect.StripTrailingEmptyLines(state.String()))
}

Documentation

Index

Constants

This section is empty.

Variables

View Source 
var ConfirmQuestionTemplate = `` /* 497-byte string literal not displayed */

Templates with Color formatting. See Documentation: https://github.com/mgutz/ansi#style-format

View Source 
var DefaultAskOptions = AskOptions{
	Stdio: terminal.Stdio{
		In:  os.Stdin,
		Out: os.Stdout,
		Err: os.Stderr,
	},
}

DefaultAskOptions is the default options on ask, using the OS stdio.

View Source 
var EditorQuestionTemplate = `` /* 582-byte string literal not displayed */

Templates with Color formatting. See Documentation: https://github.com/mgutz/ansi#style-format

View Source 
var InputQuestionTemplate = `` /* 496-byte string literal not displayed */

Templates with Color formatting. See Documentation: https://github.com/mgutz/ansi#style-format

View Source 
var MultiSelectQuestionTemplate = `` /* 858-byte string literal not displayed */
View Source 
var PageSize = 7

PageSize is the default maximum number of items to show in select/multiselect prompts

View Source 
var PasswordQuestionTemplate = `` /* 318-byte string literal not displayed */

Templates with Color formatting. See Documentation: https://github.com/mgutz/ansi#style-format

View Source 
var SelectQuestionTemplate = `` /* 719-byte string literal not displayed */

Functions

func Ask 

func Ask(qs []*Question, response interface{}, opts ...AskOpt) error

Ask performs the prompt loop, asking for validation when appropriate. The response type can be one of two options. If a struct is passed, the answer will be written to the field whose name matches the Name field on the corresponding question. Field types should be something that can be casted from the response type designated in the documentation. Note, a survey tag can also be used to identify a Otherwise, a map[string]interface{} can be passed, responses will be written to the key with the matching name. For example: 

qs := []*survey.Question{
	{
		Name:     "name",
		Prompt:   &survey.Input{Message: "What is your name?"},
		Validate: survey.Required,
		Transform: survey.Title,
	},
}

answers := struct{ Name string }{}

err := survey.Ask(qs, &answers)

func AskOne 

func AskOne(p Prompt, response interface{}, v Validator, opts ...AskOpt) error

AskOne performs the prompt for a single prompt and asks for validation if required. Response types should be something that can be casted from the response type designated in the documentation. For example: 

name := ""
prompt := &survey.Input{
	Message: "name",
}

survey.AskOne(prompt, &name, nil)

func Required 

func Required(val interface{}) error

Required does not allow an empty value

func Title added in v1.4.0 

func Title(ans interface{}) interface{}

Title is a `Transformer`. It receives an answer value and returns a copy of the "ans" with all Unicode letters that begin words mapped to their title case.

Note that if "ans" is not a string then it will return a nil value, meaning that the above answer will not be affected by this call at all.

func ToLower added in v1.4.0 

func ToLower(ans interface{}) interface{}

ToLower is a `Transformer`. It receives an answer value and returns a copy of the "ans" with all Unicode letters mapped to their lower case.

Note that if "ans" is not a string then it will return a nil value, meaning that the above answer will not be affected by this call at all.

Types

type AskOpt added in v1.6.0 

type AskOpt func(options *AskOptions) error

AskOpt allows setting optional ask options.

func WithStdio added in v1.6.0 

func WithStdio(in terminal.FileReader, out terminal.FileWriter, err io.Writer) AskOpt

WithStdio specifies the standard input, output and error files survey interacts with. By default, these are os.Stdin, os.Stdout, and os.Stderr.

type AskOptions added in v1.6.0 

type AskOptions struct {
	Stdio terminal.Stdio
}

AskOptions provides additional options on ask.

type Confirm 

type Confirm struct {
	core.Renderer
	Message string
	Default bool
	Help    string
}

Confirm is a regular text input that accept yes/no answers. Response type is a bool.

func (*Confirm) Cleanup 

func (c *Confirm) Cleanup(val interface{}) error

Cleanup overwrite the line with the finalized formatted version

func (*Confirm) Prompt 

func (c *Confirm) Prompt() (interface{}, error)

Prompt prompts the user with a simple text field and expects a reply followed by a carriage return. 

likesPie := false
prompt := &survey.Confirm{ Message: "What is your name?" }
survey.AskOne(prompt, &likesPie, nil)

type ConfirmTemplateData 

type ConfirmTemplateData struct {
	Confirm
	Answer   string
	ShowHelp bool
}

data available to the templates when processing

type Editor added in v1.3.0 

type Editor struct {
	core.Renderer
	Message       string
	Default       string
	Help          string
	Editor        string
	HideDefault   bool
	AppendDefault bool
}

Editor launches an instance of the users preferred editor on a temporary file. The editor to use is determined by reading the $VISUAL or $EDITOR environment variables. If neither of those are present, notepad (on Windows) or vim (others) is used. The launch of the editor is triggered by the enter key. Since the response may be long, it will not be echoed as Input does, instead, it print <Received>. Response type is a string. 

message := ""
prompt := &survey.Editor{ Message: "What is your commit message?" }
survey.AskOne(prompt, &message, nil)

func (*Editor) Cleanup added in v1.3.0 

func (e *Editor) Cleanup(val interface{}) error

func (*Editor) Prompt added in v1.3.0 

func (e *Editor) Prompt() (interface{}, error)

type EditorTemplateData added in v1.3.0 

type EditorTemplateData struct {
	Editor
	Answer     string
	ShowAnswer bool
	ShowHelp   bool
}

data available to the templates when processing

type Input 

type Input struct {
	core.Renderer
	Message string
	Default string
	Help    string
}

Input is a regular text input that prints each character the user types on the screen and accepts the input with the enter key. Response type is a string. 

name := ""
prompt := &survey.Input{ Message: "What is your name?" }
survey.AskOne(prompt, &name, nil)

func (*Input) Cleanup 

func (i *Input) Cleanup(val interface{}) error

func (*Input) Prompt 

func (i *Input) Prompt() (interface{}, error)

type InputTemplateData 

type InputTemplateData struct {
	Input
	Answer     string
	ShowAnswer bool
	ShowHelp   bool
}

data available to the templates when processing

type MultiSelect added in v1.0.1 

type MultiSelect struct {
	core.Renderer
	Message       string
	Options       []string
	Default       []string
	Help          string
	PageSize      int
	VimMode       bool
	FilterMessage string
	// contains filtered or unexported fields
}

MultiSelect is a prompt that presents a list of various options to the user for them to select using the arrow keys and enter. Response type is a slice of strings. 

days := []string{}
prompt := &survey.MultiSelect{
	Message: "What days do you prefer:",
	Options: []string{"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"},
}
survey.AskOne(prompt, &days, nil)

func (*MultiSelect) Cleanup added in v1.0.1 

func (m *MultiSelect) Cleanup(val interface{}) error

Cleanup removes the options section, and renders the ask like a normal question.

func (*MultiSelect) OnChange added in v1.0.1 

func (m *MultiSelect) OnChange(line []rune, pos int, key rune) (newLine []rune, newPos int, ok bool)

OnChange is called on every keypress.

func (*MultiSelect) Prompt added in v1.0.1 

func (m *MultiSelect) Prompt() (interface{}, error)

type MultiSelectTemplateData added in v1.0.1 

type MultiSelectTemplateData struct {
	MultiSelect
	Answer        string
	ShowAnswer    bool
	Checked       map[string]bool
	SelectedIndex int
	ShowHelp      bool
	PageEntries   []string
}

data available to the templates when processing

type Password 

type Password struct {
	core.Renderer
	Message string
	Help    string
}

Password is like a normal Input but the text shows up as *'s and there is no default. Response type is a string. 

password := ""
prompt := &survey.Password{ Message: "Please type your password" }
survey.AskOne(prompt, &password, nil)

func (*Password) Cleanup 

func (prompt *Password) Cleanup(val interface{}) error

Cleanup hides the string with a fixed number of characters.

func (*Password) Prompt 

func (p *Password) Prompt() (line interface{}, err error)

type PasswordTemplateData added in v1.1.1 

type PasswordTemplateData struct {
	Password
	ShowHelp bool
}

type Prompt 

type Prompt interface {
	Prompt() (interface{}, error)
	Cleanup(interface{}) error
	Error(error) error
}

Prompt is the primary interface for the objects that can take user input and return a response.

type Question 

type Question struct {
	Name      string
	Prompt    Prompt
	Validate  Validator
	Transform Transformer
}

Question is the core data structure for a survey questionnaire.

type Select added in v1.0.1 

type Select struct {
	core.Renderer
	Message       string
	Options       []string
	Default       string
	Help          string
	PageSize      int
	VimMode       bool
	FilterMessage string
	// contains filtered or unexported fields
}

Select is a prompt that presents a list of various options to the user for them to select using the arrow keys and enter. Response type is a string. 

color := ""
prompt := &survey.Select{
	Message: "Choose a color:",
	Options: []string{"red", "blue", "green"},
}
survey.AskOne(prompt, &color, nil)

func (*Select) Cleanup added in v1.0.1 

func (s *Select) Cleanup(val interface{}) error

func (*Select) OnChange added in v1.0.1 

func (s *Select) OnChange(line []rune, pos int, key rune) (newLine []rune, newPos int, ok bool)

OnChange is called on every keypress.

func (*Select) Prompt added in v1.0.1 

func (s *Select) Prompt() (interface{}, error)

type SelectTemplateData 

type SelectTemplateData struct {
	Select
	PageEntries   []string
	SelectedIndex int
	Answer        string
	ShowAnswer    bool
	ShowHelp      bool
}

the data available to the templates when processing

type Transformer added in v1.4.0 

type Transformer func(ans interface{}) (newAns interface{})

Transformer is a function passed to a Question after a user has provided a response. The function can be used to implement a custom logic that will result to return a different representation of the given answer.

Look `TransformString`, `ToLower` `Title` and `ComposeTransformers` for more.

func ComposeTransformers added in v1.4.0 

func ComposeTransformers(transformers ...Transformer) Transformer

ComposeTransformers is a variadic function used to create one transformer from many.

func TransformString added in v1.4.0 

func TransformString(f func(s string) string) Transformer

TransformString returns a `Transformer` based on the "f" function which accepts a string representation of the answer and returns a new one, transformed, answer. Take for example the functions inside the std `strings` package, they can be converted to a compatible `Transformer` by using this function, i.e: `TransformString(strings.Title)`, `TransformString(strings.ToUpper)`.

Note that `TransformString` is just a helper, `Transformer` can be used to transform any type of answer.

type Validator 

type Validator func(ans interface{}) error

Validator is a function passed to a Question after a user has provided a response. If the function returns an error, then the user will be prompted again for another response.

func ComposeValidators 

func ComposeValidators(validators ...Validator) Validator

ComposeValidators is a variadic function used to create one validator from many.

func MaxLength 

func MaxLength(length int) Validator

MaxLength requires that the string is no longer than the specified value

func MinLength 

func MinLength(length int) Validator

MinLength requires that the string is longer or equal in length to the specified value

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