Zack Scholl

Progress bar

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A simple thread-safe Go library progress bar.

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


Basic usage

bar := progressbar.Default(100)
for i := 0; i < 100; i++ {
    time.Sleep(40 * time.Millisecond)

which looks like:

Example of basic bar

I/O operations

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.

req, _ := http.NewRequest("GET", "", nil)
resp, _ := http.DefaultClient.Do(req)
defer resp.Body.Close()

f, _ := os.OpenFile("go1.14.2.src.tar.gz", os.O_CREATE|os.O_WRONLY, 0644)
defer f.Close()

bar := progressbar.DefaultBytes(
io.Copy(io.MultiWriter(f, bar), resp.Body)

which looks like:

Example of download bar

Progress bar with unknown length

A progressbar with unknown length is a spinner. Any bar with -1 length will automatically convert it to a spinner with a customizable spinner type. For example, the above code can be run and set the resp.ContentLength to -1.

which looks like:

Example of download bar with unknown length


There is a lot of customization that you can do - change the writer, the color, the width, description, theme, etc. See all the options.

bar := progressbar.NewOptions(1000,
    progressbar.OptionSetDescription("[cyan][1/3][reset] Writing moshable file..."),
        Saucer:        "[green]=[reset]",
        SaucerHead:    "[green]>[reset]",
        SaucerPadding: " ",
        BarStart:      "[",
        BarEnd:        "]",
for i := 0; i < 1000; i++ {
    time.Sleep(5 * time.Millisecond)

which looks like: Example of customized bar


Pull requests are welcome. Feel free to…


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!

Thanks @Benzammour and @haseth for helping create v3!

Thanks @briandowns for compiling the list of spinners.