Printer

Overview

Printer provides a comprehensive set of utilities for formatting terminal output, including colored text, tables, spinners, progress bars, markdown rendering, and structured data output (JSON/YAML).

Text Output

Colored text output functions with support for different message types.

Success

Prints success messages in green.

func Success(t ...string)
func Successln(t ...string)
func Successf(t string, args ...interface{})

...string

Messages to print in green

Example:

printer.Success("Deployment completed")
printer.Successln("Build", " ", "successful")
printer.Successf("Deployed %d services", 5)

Warning

Prints warning messages in yellow.

func Warning(t ...string)
func Warningln(t ...string)
func Warningf(t string, args ...interface{})

...string

Messages to print in yellow

Example:

printer.Warning("Deprecated feature")
printer.Warningln("This will be removed in v2.0")
printer.Warningf("Found %d warnings", 3)

Error

Prints error messages in red.

func Error(t ...string)
func Errorln(t ...string)
func Errorf(t string, args ...interface{})

...string

Messages to print in red

Example:

printer.Error("Connection failed")
printer.Errorln("Unable to reach server")
printer.Errorf("Error: %v", err)

Info

Prints informational messages in cyan.

func Info(t ...string)
func Infoln(t ...string)
func Infof(t string, args ...interface{})

...string

Messages to print in cyan

Example:

printer.Info("Starting deployment")
printer.Infoln("Connecting to server...")
printer.Infof("Processing %d items", 100)

Text Styles

Format text with bold or italic styles.

func Bold(t ...string) string
func Boldln(t ...string)
func Boldf(t string, args ...interface{}) string

func Italic(t ...string) string
func Italicln(t ...string)
func Italicf(t string, args ...interface{}) string

Example:

fmt.Println(printer.Bold("Important:"), "Read this carefully")
printer.Boldln("Configuration")
title := printer.Boldf("Section %d", 1)

fmt.Println(printer.Italic("Note:"), "Optional parameter")
printer.Italicln("Deprecated")

Color Functions

Direct color output with theme support (automatically adapts to light/dark terminals).

Available Colors

func Green(t ...string) string
func Greenf(t string, args ...interface{}) string

func Yellow(t ...string) string
func Yellowf(t string, args ...interface{}) string

func Cyan(t ...string) string
func Cyanf(t string, args ...interface{}) string

func Red(t ...string) string
func Redf(t string, args ...interface{}) string

func Blue(t ...string) string
func Bluef(t string, args ...interface{}) string

func Grey(t ...string) string
func Greyf(t string, args ...interface{}) string

func Magenta(t ...string) string
func Magentaf(t string, args ...interface{}) string

Example:

fmt.Println(printer.Green("Success"))
fmt.Println(printer.Yellowf("Warning: %s", msg))
fmt.Println(printer.Cyan("Info"), printer.Grey("details"))

Icon

Returns Unicode icons for common message types.

func Icon(name string) string

name

string

required

Icon name: “success”, “failure”, “info”, or “warning”

icon

string

Unicode character: ✔ (success), ✘ (failure), ℹ (info), ⚠ (warning)

Example:

fmt.Printf("%s Build successful\n", printer.Icon("success"))
fmt.Printf("%s Deployment failed\n", printer.Icon("failure"))

Theme

Color theme that adapts to terminal background (light/dark).

type Theme struct {
    Green   termenv.Color
    Yellow  termenv.Color
    Cyan    termenv.Color
    Red     termenv.Color
    Grey    termenv.Color
    Blue    termenv.Color
    Magenta termenv.Color
}

func NewTheme() Theme

Table Output

Render data in a clean, terminal-friendly table format.

Table

func Table(target io.Writer, rows [][]string)

target

io.Writer

required

Output destination (e.g., os.Stdout)

rows

[][]string

required

2D slice where each inner slice is a row, and elements are column values

Features:

Disables text wrapping
Left-aligned headers and content
No borders or separators
Tab padding for clean alignment

Example:

rows := [][]string{
    {"ID", "Name", "Status"},
    {"1", "service-a", "running"},
    {"2", "service-b", "stopped"},
    {"3", "service-c", "running"},
}

printer.Table(os.Stdout, rows)
// Output:
// ID    Name        Status
// 1     service-a   running
// 2     service-b   stopped
// 3     service-c   running

Structured Output

Output data in JSON or YAML format.

JSON

Prints data in compact JSON format.

func JSON(data interface{}) error

data

interface{}

required

Data structure to marshal as JSON

Example:

data := map[string]interface{}{
    "name": "service-a",
    "status": "running",
    "port": 8080,
}

if err := printer.JSON(data); err != nil {
    log.Fatal(err)
}
// Output: {"name":"service-a","status":"running","port":8080}

PrettyJSON

Prints data in indented, readable JSON format.

func PrettyJSON(data interface{}) error

data

interface{}

required

Data structure to marshal as pretty-printed JSON

Example:

if err := printer.PrettyJSON(data); err != nil {
    log.Fatal(err)
}
// Output:
// {
//     "name": "service-a",
//     "status": "running",
//     "port": 8080
// }

YAML

Prints data in YAML format.

func YAML(data interface{}) error

data

interface{}

required

Data structure to marshal as YAML

Example:

if err := printer.YAML(data); err != nil {
    log.Fatal(err)
}
// Output:
// name: service-a
// status: running
// port: 8080

File

Generic function to output data in a specified format.

func File(data interface{}, format string) error

data

interface{}

required

Data structure to marshal

format

string

required

Format: “json”, “prettyjson”, or “yaml”

Example:

format := "yaml" // from user flag
if err := printer.File(data, format); err != nil {
    log.Fatal(err)
}

Progress Indicators

Spinner

Display an animated spinner for long-running operations.

type Indicator struct {
    // Internal spinner instance
}

func Spin(label string) *Indicator
func (s *Indicator) Stop()

label

string

Text to display next to the spinner

Indicator

*Indicator

Spinner instance that can be stopped

Example:

spinner := printer.Spin("Deploying application")
// Perform long-running operation
time.Sleep(5 * time.Second)
spinner.Stop()
printer.Successln("Deployment complete")

Features:

Automatically disabled on non-TTY terminals
Cyan color by default
120ms update interval

Progress Bar

Display a progress bar for tracked operations.

func Progress(max int, description string) *progressbar.ProgressBar

max

int

required

Maximum value (100% completion)

description

string

required

Description of the operation

bar

*progressbar.ProgressBar

Progress bar instance from github.com/schollz/progressbar/v3

Example:

bar := printer.Progress(100, "Downloading files")
for i := 0; i < 100; i++ {
    // Simulate work
    time.Sleep(50 * time.Millisecond)
    bar.Add(1)
}
fmt.Println()
printer.Successln("Download complete")

Markdown Rendering

Render markdown with terminal colors and formatting.

Markdown

Renders markdown with default options (auto-style, emoji, no wrap).

func Markdown(text string) (string, error)

text

string

required

Markdown text to render

output

string

Rendered markdown with ANSI colors

Example:

md := `
# Title

This is **bold** and this is *italic*.

- Item 1
- Item 2

` + "```" + `go
fmt.Println("Hello")
` + "```" + `
`

rendered, err := printer.Markdown(md)
if err != nil {
    log.Fatal(err)
}
fmt.Print(rendered)

MarkdownWithWrap

Renders markdown with word wrapping at specified width.

func MarkdownWithWrap(text string, wrap int) (string, error)

text

string

required

Markdown text to render

wrap

int

required

Word wrap width in characters

Example:

rendered, err := printer.MarkdownWithWrap(longText, 80)
if err != nil {
    log.Fatal(err)
}
fmt.Print(rendered)

Utility Functions

Space

Prints a single space character.

func Space()

Example:

printer.Info("Status:")
printer.Space()
printer.Success("OK")
// Output: Status: OK (with colors)

Complete Example

package main

import (
    "os"
    "time"
    
    "github.com/raystack/salt/cli/printer"
)

func main() {
    // Print status messages
    printer.Infoln("Starting deployment process...")
    printer.Space()

    // Show spinner during operation
    spinner := printer.Spin("Initializing")
    time.Sleep(2 * time.Second)
    spinner.Stop()
    printer.Successln("Initialized")

    // Show progress bar
    bar := printer.Progress(100, "Deploying services")
    for i := 0; i < 100; i++ {
        time.Sleep(50 * time.Millisecond)
        bar.Add(1)
    }
    fmt.Println()

    // Display results in table
    results := [][]string{
        {"Service", "Status", "Port"},
        {"api", "running", "8080"},
        {"web", "running", "3000"},
        {"worker", "running", "-"},
    }
    printer.Table(os.Stdout, results)
    printer.Space()

    // Output structured data
    data := map[string]interface{}{
        "deployed": 3,
        "failed":   0,
        "duration": "5.2s",
    }
    
    printer.Infoln("Deployment summary:")
    printer.PrettyJSON(data)
    printer.Space()

    // Final status
    fmt.Printf("%s ", printer.Icon("success"))
    printer.Successln("Deployment completed successfully")
}

Core

CLI

Authentication

Infrastructure

Utilities

Overview

Text Output

Success

Warning

Error

Info

Text Styles

Color Functions

Available Colors

Icon

Theme

Table Output

Table

Structured Output

JSON

PrettyJSON

YAML

File

Progress Indicators

Spinner

Progress Bar

Markdown Rendering

Markdown

MarkdownWithWrap

Utility Functions

Space

Complete Example

Build docs developers (and LLMs) love

Core

CLI

Authentication

Infrastructure

Utilities

​Overview

​Text Output

​Success

​Warning

​Error

​Info

​Text Styles

​Color Functions

​Available Colors

​Icon

​Theme

​Table Output

​Table

​Structured Output

​JSON

​PrettyJSON

​YAML

​File

​Progress Indicators

​Spinner

​Progress Bar

​Markdown Rendering

​Markdown

​MarkdownWithWrap

​Utility Functions

​Space

​Complete Example

Build docs developers (and LLMs) love

Overview

Text Output

Success

Warning

Error

Info

Text Styles

Color Functions

Available Colors

Icon

Theme

Table Output

Table

Structured Output

JSON

PrettyJSON

YAML

File

Progress Indicators

Spinner

Progress Bar

Markdown Rendering

Markdown

MarkdownWithWrap

Utility Functions

Space

Complete Example