github.com/5Sigma/vox

Vox is a Go package designed to help make terminal/console applications more attractive.

It is a collection of small helper functions that aid in printing various pieces of information to the console.

• Various predefined and common printing tasks like printing property key/value pairs, result responses, etc.
• Print JSON data with syntax highlighting
• Easily print colorized output
• Display real time progress bars for tasks
• Easy helper functions for printing various types of messages: Alerts, errors, debug messages, etc.
• Control the output and input streams to help during application testing.

Usage

import "github.com/5sigma/vox"

Printing with color

There are a number of functions that allow printing arbitrary text with colors such as Printc, Printlnc, and Sprintc. These all take a color as their first argument and printable objects after them. They will also append a color reset to the end.

  vox.Printlnc(vox.Red, "Hello, I am red")

Printing complex color coded text can be slightly more complicated. The basic printing functions will remove their color codes for output Pipelines that are considered Plain, such as the FilePipeline. To print complex color coded text something like this could be used:

vox.Print("I am")
vox.Printc(vox.Green, "green ")
vox.Print(" and ")
vox.Printc(vox.Red, " red", vox.ResetColor)
vox..Print("\n")

Although a better solution maybe to use the PrintRich and PrintPlain functions which will only output to plain or non plain Pipelines.

vox.PrintRich("I am ", vox.Green, "green ", vox.ResetColor, " and ", vox.Red, "red", vox.ResetColor)
vox.PrintPlain("I am green and red)

Colors

The following color constants exist, along with a ResetColor constant:

• Black
• Red
• Green
• Yellow
• Blue
• Magenta
• Cyan
• White

Loglevel functions

The loglevel functions print standard types of messages (debug, error, alert, info) colored and formatted. See the package documentation for their definitions.

vox.Debug("hai")
vox.Alert("oh no")
vox.Info("this thing happened")
vox.Error("whoops")

Printing results

Prints a key and a result string depending on if the error value is nil.

err := writeFile()
vox.PrintResult("Writing file", err)

Task: [OK] Task2: [FAIL]

• Error messsage Task3: [OK]

Printing property lists

Prints a key and value and pads them to align on the edges of the screen.

vox.PrintResult("Name", user.Name)
vox.PrintResult("Email", user.Email)

Key:                                   some value
Key:                                   some value
Key:                                   some value

Prompting for input

Prompting for a basic string response from the user:

result := vox.Prompt("Enter a response", "none")
vox.Println("You entered ", result)

Prompting for a boolean response:

result := vox.PromptBool("Are you sure", false)
if !result {
  return
}

Prompting for a choice of options:

choices := []string{"Option 1", "Option 2", "Option 3"}
resultIndex := vox.PromptChoice("Choose an option", choices, 0)

Displaying progress

The progress bar is controlled using StartProgress, IncProgress, and SetProgress.

vox.StartProgress(0, len(myTasks))
for _, t := range myTasks {
  err := doTask(myTask)
  if err != nil {
    vox.Error(err.Error())
    break
  }
  vox.IncProgress()
}
vox.StopProgress()

Testing

A testing pipeline is provided that directs all output into an internal string slice. It also provides utility functions to make accessing values easier.

v := vox.New()
pipline = vox.TestPipeline{}
v.SetPipelines(pipeline)
v.Print("test")
if (pipeline.Last() != "test" {
  t.Error("not test")
}

A Test helper function is provided to make this easier:

pipeline := vox.Test()

An example test

func AskForFile() string {
	return vox.Prompt("Enter a file", "")
}

func TestReadConfig(t *testing.T) {
	// setup for testing
	pipeline = vox.Test()

	// verify an error output
	err := checkFile()
	if pipeline.Last() != fmt.Sprint(vox.Red, "No config file found.") {
		t.Errorf("Error message not printed: %s", pipeline.Last())
	}

	// Asks user for a file path
	SendInput("test.txt")
	name := AskForFile()

	// Builds a config file
	SetupFile(name)


	err = checkFile()
	if err != nil {
		t.Errorf("Could not load config file: %s", err.Error())
	}
	if pipeline.Last() != "Config file read" {
		t.Error("Value missmatch: %s", pipeline.Last())
	}
}