commands: build summary of warnings on build

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

util/logutil/pause.go

@@ -0,0 +1,52 @@
+package logutil
+
+import (
+	"bytes"
+	"io"
+	"sync"
+
+	"github.com/sirupsen/logrus"
+)
+
+func Pause(l *logrus.Logger) func() {
+	// initialize formatter with original terminal settings
+	l.Formatter.Format(logrus.NewEntry(l))
+
+	bw := newBufferedWriter(l.Out)
+	l.SetOutput(bw)
+	return func() {
+		bw.resume()
+	}
+}
+
+type bufferedWriter struct {
+	mu  sync.Mutex
+	buf *bytes.Buffer
+	w   io.Writer
+}
+
+func newBufferedWriter(w io.Writer) *bufferedWriter {
+	return &bufferedWriter{
+		buf: bytes.NewBuffer(nil),
+		w:   w,
+	}
+}
+
+func (bw *bufferedWriter) Write(p []byte) (int, error) {
+	bw.mu.Lock()
+	defer bw.mu.Unlock()
+	if bw.buf == nil {
+		return bw.w.Write(p)
+	}
+	return bw.buf.Write(p)
+}
+
+func (bw *bufferedWriter) resume() {
+	bw.mu.Lock()
+	defer bw.mu.Unlock()
+	if bw.buf == nil {
+		return
+	}
+	io.Copy(bw.w, bw.buf)
+	bw.buf = nil
+}

util/progress/printer.go

@@ -7,8 +7,10 @@ import (
 	"os"
 
 	"github.com/containerd/console"
+	"github.com/docker/buildx/util/logutil"
 	"github.com/moby/buildkit/client"
 	"github.com/moby/buildkit/util/progress/progressui"
+	"github.com/sirupsen/logrus"
 )
 
 const (
@@ -19,9 +21,10 @@ const (
 )
 
 type Printer struct {
-	status chan *client.SolveStatus
-	done   <-chan struct{}
-	err    error
+	status   chan *client.SolveStatus
+	done     <-chan struct{}
+	err      error
+	warnings []client.VertexWarning
 }
 
 func (p *Printer) Wait() error {
@@ -34,6 +37,10 @@ func (p *Printer) Write(s *client.SolveStatus) {
 	p.status <- s
 }
 
+func (p *Printer) Warnings() []client.VertexWarning {
+	return p.warnings
+}
+
 func NewPrinter(ctx context.Context, out console.File, mode string) *Printer {
 	statusCh := make(chan *client.SolveStatus)
 	doneCh := make(chan struct{})
@@ -58,8 +65,10 @@ func NewPrinter(ctx context.Context, out console.File, mode string) *Printer {
 				c = cons
 			}
 		}
+		resumeLogs := logutil.Pause(logrus.StandardLogger())
 		// not using shared context to not disrupt display but let is finish reporting errors
-		_, pw.err = progressui.DisplaySolveStatus(ctx, "", c, w, statusCh)
+		pw.warnings, pw.err = progressui.DisplaySolveStatus(ctx, "", c, w, statusCh)
+		resumeLogs()
 		close(doneCh)
 	}()
 	return pw