feat: add 'new line' capability to spinner (#506)

we should be able to create new spinners based on what is being printed
on the screen. this is useful when we want to create multiple spinners
while running commands like `kots install`.

Author: ricardomaraschini

pkg/spinner/options.go

@@ -10,6 +10,15 @@ func WithWriter(w WriteFn) Option {
 	}
 }
 
+// WithLineBreaker sets a function that determines if if is time
+// to break the line thus creating a new spinner line. The previous
+// step is flagged as success.
+func WithLineBreaker(lb LineBreakerFn) Option {
+	return func(m *MessageWriter) {
+		m.lbreak = lb
+	}
+}
+
 // WithMask sets the MaskFn on the MessageWriter.
 func WithMask(mfn MaskFn) Option {
 	return func(m *MessageWriter) {

pkg/spinner/spinner.go

@@ -12,6 +12,11 @@ var blocks = []string{"◐", "◓", "◑", "◒"}
 // WriteFn is a function that writes a formatted string.
 type WriteFn func(string, ...any) (int, error)
 
+// LineBreakerFn is a function that determines if it is time to break the
+// line thus creating a new spinner line. The previous step is flagged as
+// success.
+type LineBreakerFn func(string) bool
+
 // MaskFn is a function that masks a message. Receives a string and
 // returns a string, the returned string is printed to the terminal.
 type MaskFn func(string) string
@@ -23,6 +28,7 @@ type MessageWriter struct {
 	err    bool
 	printf WriteFn
 	mask   MaskFn
+	lbreak LineBreakerFn
 }
 
 // Write implements io.Writer for the MessageWriter.
@@ -100,19 +106,31 @@ func (m *MessageWriter) loop() {
 		case <-ticker.C:
 			counter++
 		}
+
+		var lbreak bool
+		if m.lbreak != nil {
+			lbreak = m.lbreak(message)
+		}
+
 		if m.mask != nil {
 			message = m.mask(message)
 		}
+
 		pos := counter % len(blocks)
 		if !end {
-			_, _ = m.printf("\033[K\r%s  %s ", blocks[pos], message)
+			prefix, suffix := blocks[pos], ""
+			if lbreak {
+				prefix, suffix = "✔", "\n"
+			}
+			m.printf("\033[K\r%s  %s %s", prefix, message, suffix)
 			continue
 		}
+
 		prefix := "✔"
 		if m.err {
 			prefix = "✗"
 		}
-		_, _ = m.printf("\033[K\r%s  %s\n", prefix, message)
+		m.printf("\033[K\r%s  %s\n", prefix, message)
 		close(m.end)
 		return
 	}

pkg/spinner/spinner_test.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"fmt"
 	"io"
+	"strings"
 	"testing"
 	"time"
 
@@ -107,3 +108,26 @@ func TestMask(t *testing.T) {
 	assert.Contains(t, buf.String(), "masked 0")
 	assert.Contains(t, buf.String(), "masked 1")
 }
+
+func TestLineBreak(t *testing.T) {
+	buf := bytes.NewBuffer(nil)
+	lbreak := func(s string) bool {
+		return s == "test 3" || s == "test 8"
+	}
+	pb := Start(
+		WithWriter(WriteTo(buf)),
+		WithLineBreaker(lbreak),
+	)
+	for i := 0; i < 100; i++ {
+		pb.Infof("test %d", i)
+	}
+	pb.Close()
+	// we expect the following output:
+	// ✔  test 3 (\n)
+	// ✔  test 8 (\n)
+	// ✔  test 99 (\n)
+	assert.Equal(t, strings.Count(buf.String(), "\n"), 3)
+	assert.Contains(t, buf.String(), "test 3")
+	assert.Contains(t, buf.String(), "test 8")
+	assert.Contains(t, buf.String(), "test 99")
+}