progress: avoid double logs when multiple targets build same step

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

util/progress/printer.go

@@ -5,11 +5,13 @@ import (
 	"io"
 	"io/ioutil"
 	"os"
+	"sync"
 
 	"github.com/containerd/console"
 	"github.com/docker/buildx/util/logutil"
 	"github.com/moby/buildkit/client"
 	"github.com/moby/buildkit/util/progress/progressui"
+	"github.com/opencontainers/go-digest"
 	"github.com/sirupsen/logrus"
 )
 
@@ -21,10 +23,12 @@ const (
 )
 
 type Printer struct {
-	status   chan *client.SolveStatus
-	done     <-chan struct{}
-	err      error
-	warnings []client.VertexWarning
+	status       chan *client.SolveStatus
+	done         <-chan struct{}
+	err          error
+	warnings     []client.VertexWarning
+	logMu        sync.Mutex
+	logSourceMap map[digest.Digest]interface{}
 }
 
 func (p *Printer) Wait() error {
@@ -41,13 +45,39 @@ func (p *Printer) Warnings() []client.VertexWarning {
 	return p.warnings
 }
 
+func (p *Printer) ValidateLogSource(dgst digest.Digest, v interface{}) bool {
+	p.logMu.Lock()
+	defer p.logMu.Unlock()
+	src, ok := p.logSourceMap[dgst]
+	if ok {
+		if src == v {
+			return true
+		}
+	} else {
+		p.logSourceMap[dgst] = v
+		return true
+	}
+	return false
+}
+
+func (p *Printer) ClearLogSource(v interface{}) {
+	p.logMu.Lock()
+	defer p.logMu.Unlock()
+	for d := range p.logSourceMap {
+		if p.logSourceMap[d] == v {
+			delete(p.logSourceMap, d)
+		}
+	}
+}
+
 func NewPrinter(ctx context.Context, w io.Writer, out console.File, mode string) *Printer {
 	statusCh := make(chan *client.SolveStatus)
 	doneCh := make(chan struct{})
 
 	pw := &Printer{
-		status: statusCh,
-		done:   doneCh,
+		status:       statusCh,
+		done:         doneCh,
+		logSourceMap: map[digest.Digest]interface{}{},
 	}
 
 	if v := os.Getenv("BUILDKIT_PROGRESS"); v != "" && mode == PrinterModeAuto {