Start and Stop twice make program panic

[jtbonhomme]

Hello,
I may be missing a point, but it seems that starting and stoping a uiprogress twice make the program panic.

Please find bellow a short test program:

package main

import (
    "fmt"
    "time"

    "github.com/gosuri/uiprogress"
)

func createbar() {
    uiprogress.Start()
    defer uiprogress.Stop()
    // create a new bar and prepend the task progress to the bar
    count := 100
    bar := uiprogress.AddBar(count).AppendCompleted().PrependElapsed()
    bar.PrependFunc(func(b *uiprogress.Bar) string {
        return fmt.Sprintf("Task (%d/%d)", b.Current(), count)
    })

    for i := 0; i < count; i++ {
            bar.Incr()
            time.Sleep(time.Millisecond * time.Duration(50))
    }
    time.Sleep(time.Millisecond * time.Duration(500))
}

func main() {
  createbar()
  createbar()
}

The console:

$ go run main.go
Task (100/100)    5s [====================================================================] 100%
Task (1/100)    0s [--------------------------------------------------------------------]   1%
panic: close of closed channel

goroutine 20 [running]:
github.com/gosuri/uiprogress.(*Progress).Listen(0xc00007a1e0)
	/Users/jtbonhomme/Developments/golang/src/github.com/gosuri/uiprogress/progress.go:117 +0x12f
created by github.com/gosuri/uiprogress.(*Progress).Start
	/Users/jtbonhomme/Developments/golang/src/github.com/gosuri/uiprogress/progress.go:134 +0x3f
exit status 2

[danlamanna]

I'm also experiencing this issue.

[Che4ter]

I have the same issue..

[ubiuser]

I don't think this is a bug, but it definitely needs an example to document this use case for clarity.

Here is what's happening:
uiprogress.Start() and uiprogress.Stop() are using defaultProgress which is initialised with New(), thus defaultProgress is a Progress object that has a tdone channel. In Go, once a channel is closed (calling Stop() in this case) it cannot be reopened or closed again.

Solution:
A new Progress instance must be created with New and call Start/Stop on this object.

package main

import (
    "fmt"
    "time"

    "github.com/gosuri/uiprogress"
)

func createbar() {
    uip := uiprogress.New()
    uip.Start()
    defer uip.Stop()
    // create a new bar and prepend the task progress to the bar
    count := 100
    bar := uip.AddBar(count).AppendCompleted().PrependElapsed()
    bar.PrependFunc(func(b *uiprogress.Bar) string {
        return fmt.Sprintf("Task (%d/%d)", b.Current(), count)
    })

    for i := 0; i < count; i++ {
        bar.Incr()
        time.Sleep(time.Millisecond * time.Duration(50))
    }
    time.Sleep(time.Millisecond * time.Duration(500))
}

func main() {
    createbar()
    createbar()
}