goprogressor

goprogressor

A Go library to render progress bars in terminal applications. It provides a set of flexible features with a customizable API.

Progress bars improve readability for terminal applications with long outputs by providing a concise feedback loop.

Features

• Multiple Bars: goprogressor can render multiple progress bars that can be tracked concurrently
• Dynamic Addition: Add additional progress bars any time, even after the progress tracking has started
• Prepend and Append Functions: Append or prepend completion percent and time elapsed to the progress bars
• Custom Decorator Functions: Add custom functions around the bar along with helper functions

Usage

To start listening for progress bars, call goprogressor.Start() and add a progress bar using goprogressor.AddBar(total int). Update the progress using bar.Incr() or bar.Set(n int). Full source code for the below example is available at example/simple/simple.go

goprogressor.Start()            // start rendering
bar := goprogressor.AddBar(100) // Add a new bar

// optionally, append and prepend completion and elapsed time
bar.AppendCompleted()
bar.PrependElapsed()

for bar.Incr() {
  time.Sleep(time.Millisecond * 20)
}

This will render the below in the terminal

Using Custom Decorators

You can also add a custom decorator function in addition to default bar.AppendCompleted() and bar.PrependElapsed() decorators. The below example tracks the current step for an application deploy progress. Source code for the below example is available at example/full/full.go

var steps = []string{"downloading source", "installing deps", "compiling", "packaging", "seeding database", "deploying", "staring servers"}
bar := goprogressor.AddBar(len(steps))

// prepend the current step to the bar
bar.PrependFunc(func(b *goprogressor.Bar) string {
  return "app: " + steps[b.Current()-1]
})

for bar.Incr() {
  time.Sleep(time.Millisecond * 10)
}

Rendering Multiple bars

You can add multiple bars using goprogressor.AddBar(n). The below example demonstrates updating multiple bars concurrently and adding a new bar later in the pipeline. Source for this example is available at example/multi/multi.go

waitTime := time.Millisecond * 100
goprogressor.Start()

// start the progress bars in go routines
var wg sync.WaitGroup

bar1 := goprogressor.AddBar(20).AppendCompleted().PrependElapsed()
wg.Add(1)
go func() {
  defer wg.Done()
  for bar1.Incr() {
    time.Sleep(waitTime)
  }
}()

bar2 := goprogressor.AddBar(40).AppendCompleted().PrependElapsed()
wg.Add(1)
go func() {
  defer wg.Done()
  for bar2.Incr() {
    time.Sleep(waitTime)
  }
}()

time.Sleep(time.Second)
bar3 := goprogressor.AddBar(20).PrependElapsed().AppendCompleted()
wg.Add(1)
go func() {
  defer wg.Done()
  for i := 1; i <= bar3.Total; i++ {
    bar3.Set(i)
    time.Sleep(waitTime)
  }
}()

// wait for all the go routines to finish
wg.Wait()

This will produce

Incr counter

Bar.Incr() is an atomic counter and can be used as a general tracker, making it ideal for tracking progress of work fanned out to a lots of go routines. The source code for the below example is available at example/incr/incr.go

runtime.GOMAXPROCS(runtime.NumCPU()) // use all available cpu cores

// create a new bar and prepend the task progress to the bar and fanout into 1k go routines
count := 1000
bar := goprogressor.AddBar(count).AppendCompleted().PrependElapsed()
bar.PrependFunc(func(b *goprogressor.Bar) string {
  return fmt.Sprintf("Task (%d/%d)", b.Current(), count)
})

goprogressor.Start()
var wg sync.WaitGroup

// fanout into go routines
for i := 0; i < count; i++ {
  wg.Add(1)
  go func() {
    defer wg.Done()
    time.Sleep(time.Millisecond * time.Duration(rand.Intn(500)))
    bar.Incr()
  }()
}
time.Sleep(time.Second) // wait for a second for all the go routines to finish
wg.Wait()
goprogressor.Stop()

Installation

$ go get -v gitee.com/shirdonl/goProgressor

Todos

• Resize bars and decorators by auto detecting window's dimensions
• Handle more progress bars than vertical screen allows

License

goprogressor is released under the MIT License. See LICENSE.