A very simple thread-safe progress bar which should work on every OS without problems. I needed a progressbar for croc and everything I tried had problems, so I made another one. In order to be OS agnostic I do not plan to support multi-line outputs.

go get -u github.com/schollz/progressbar/v2

bar := progressbar.New(100)
for i := 0; i < 100; i++ {
    bar.Add(1)
    time.Sleep(10 * time.Millisecond)
}

which looks like:

 100% |████████████████████████████████████████| [1s:0s]

The times at the end show the elapsed time and the remaining time, respectively.

For long running processes, you might want to render from a 0% state.

// Renders the bar right on construction
bar := progressbar.NewOptions(100, progressbar.OptionSetRenderBlankState(true))

Alternatively, when you want to delay rendering, but still want to render a 0% state

bar := progressbar.NewOptions(100)

// Render the current state, which is 0% in this case
bar.RenderBlank()

// Emulate work
for i := 0; i < 10; i++ {
    time.Sleep(10 * time.Minute)
    bar.Add(10)
}

The default writer is standard output (os.Stdout), but you can set it to whatever satisfies io.Writer.

bar := NewOptions(
    10,
    OptionSetTheme(Theme{Saucer: "#", SaucerPadding: "-", BarStart: ">", BarEnd: "<"}),
    OptionSetWidth(10),
    OptionSetWriter(&buf),
)

bar.Add(5)
result := strings.TrimSpace(buf.String())

// Result equals:
// 50% >#####-----< [0s:0s]

The progressbar implements an io.Writer so it can automatically detect the number of bytes written to a stream, so you can use it as a progressbar for an io.Reader.

urlToGet := "https://github.com/schollz/croc/releases/download/v4.1.4/croc_v4.1.4_Windows-64bit_GUI.zip"
req, _ := http.NewRequest("GET", urlToGet, nil)
resp, _ := http.DefaultClient.Do(req)
defer resp.Body.Close()

var out io.Writer
f, _ := os.OpenFile("croc_v4.1.4_Windows-64bit_GUI.zip", os.O_CREATE|os.O_WRONLY, 0644)
out = f
defer f.Close()

bar := progressbar.NewOptions(
    int(resp.ContentLength), 
    progressbar.OptionSetBytes(int(resp.ContentLength)),
)
out = io.MultiWriter(out, bar)
io.Copy(out, resp.Body)

See the tests for another example.

The progressbar implements ChangeMax and ChangeMax64 functions to change the max value of the progress bar.

bar := progressbar.New(100)
bar.ChangeMax(200) // Change the max of the progress bar to 200, not 100

You can also use ChangeMax64 to minimize casting in the library. See the tests for another example.

By default the progress bar will attempt to predict the remaining amount of time left. This can be change to just show the current increment over the total maximum amount set for the progress bar. Do this by using the OptionSetPredictTime option during progress bar creation.

bar := progressbar.NewOptions(100, progressbar.OptionSetPredictTime(false))
bar.Add(20)

// this result equals:
// "20% |██        |  [20:100]"

// default result equals:
// "20% |██        |  [3s:15s]"

If you don't know how long the given operation takes, you can opt into a pinging bar until your operation finishes. In order to activate this make sure to provide -1 as the first argument (the max argument) and set the OptionIgnoreLength() option during progress bar creation.

bar := progressbar.NewOptions(
    -1,
    OptionSetTheme(Theme{Saucer: "*", SaucerPadding: " ", BarStart: "|", BarEnd: "|"}),
    progressbar.OptionIgnoreLength(),
)

for i := 0; i < 45; i++ {
    bar.Add(1)
    time.Sleep(10 * time.Millisecond)
}

Pull requests are welcome. Feel free to...

• Revise documentation
• Add new features
• Fix bugs
• Suggest improvements

Thanks @Dynom for massive improvements in version 2.0!

Thanks @CrushedPixel for adding descriptions and color code support!

Thanks @MrMe42 for adding some minor features!

Thanks @tehstun for some great PRs!

MIT