99 lines
2.5 KiB
Go
99 lines
2.5 KiB
Go
// Copyright 2016-2017, Pulumi Corporation. All rights reserved.
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package cmdutil
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import (
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"fmt"
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"os"
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"time"
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"golang.org/x/crypto/ssh/terminal"
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)
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// NewSpinnerAndTicker returns a new Spinner and a ticker that will fire an event when the next call to Spinner.Tick()
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// should be called. NewSpinnerAndTicket takes into account if stdout is connected to a tty or not and returns either
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// a nice animated spinner that updates quickly, using the specified ttyFrames, or a simple spinner that just prints a
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// dot on each tick and updates slowly.
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func NewSpinnerAndTicker(prefix string, ttyFrames []string) (Spinner, *time.Ticker) {
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if ttyFrames == nil {
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ttyFrames = DefaultSpinFrames
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}
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if terminal.IsTerminal(int(os.Stdout.Fd())) {
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return &ttySpinner{
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prefix: prefix,
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frames: ttyFrames,
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}, time.NewTicker(time.Second / 8)
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}
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return &dotSpinner{
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prefix: prefix,
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}, time.NewTicker(time.Second * 20)
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}
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// Spinner represents a very simple progress reporter.
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type Spinner interface {
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// Print the next frame of the spinner. After Tick() has been called, there should be no writes to Stdout before
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// calling Reset().
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Tick()
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// Called to release ownership of stdout, so others may write to it.
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Reset()
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}
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var (
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// DefaultSpinFrames is the default set of symbols to show while spinning in a TTY setting.
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DefaultSpinFrames = []string{"⠋", "⠙", "⠚", "⠒", "⠂", "⠂", "⠒", "⠲", "⠴", "⠦", "⠖", "⠒", "⠐", "⠐", "⠒", "⠓", "⠋"}
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)
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// ttySpinner is the spinner that can be used when standard out is a tty. When we are connected to a TTY we can erase
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// characters we've written and provide a nice quick progress spinner.
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type ttySpinner struct {
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prefix string
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frames []string
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index int
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hasWritten bool
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}
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func (spin *ttySpinner) Tick() {
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if spin.hasWritten {
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fmt.Print("\b")
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} else {
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fmt.Print(spin.prefix)
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spin.hasWritten = true
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}
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fmt.Print(spin.frames[spin.index])
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spin.index = (spin.index + 1) % len(spin.frames)
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}
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func (spin *ttySpinner) Reset() {
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if spin.hasWritten {
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for i := 0; i < len(spin.prefix)+1; i++ {
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fmt.Print("\b")
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}
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}
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spin.index = 0
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spin.hasWritten = false
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}
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// dotSpinner is the spinner that can be used when standard out is not a tty. In this case, we just write a single
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// dot on each tick.
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type dotSpinner struct {
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prefix string
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hasWritten bool
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}
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func (spin *dotSpinner) Tick() {
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if !spin.hasWritten {
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fmt.Print(spin.prefix)
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}
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fmt.Printf(".")
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spin.hasWritten = true
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}
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func (spin *dotSpinner) Reset() {
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if spin.hasWritten {
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fmt.Println()
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}
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spin.hasWritten = false
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}
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