buildctl: make trace shutdown best effort

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

Author: crazy-max

cmd/buildctl/common/trace.go

@@ -10,6 +10,7 @@ import (
 	"github.com/moby/buildkit/util/tracing/detect"
 	"github.com/pkg/errors"
 	"github.com/urfave/cli/v3"
+	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/attribute"
 	"go.opentelemetry.io/otel/codes"
 	sdktrace "go.opentelemetry.io/otel/sdk/trace"
@@ -85,7 +86,10 @@ func AttachAppContext(app *cli.Command) error {
 		ctx, cancel := context.WithTimeoutCause(appcontext.Shutdown(), exportTimeout, errors.WithStack(context.DeadlineExceeded))
 		defer cancel()
 
-		return tp.Shutdown(ctx)
+		if err := tp.Shutdown(ctx); err != nil {
+			otel.Handle(err)
+		}
+		return nil
 	}
 	return nil
 }

cmd/buildctl/common/trace_test.go

@@ -0,0 +1,97 @@
+package common
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/moby/buildkit/util/tracing/detect"
+	"github.com/stretchr/testify/require"
+	"github.com/urfave/cli/v3"
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+)
+
+var errTraceShutdown = errors.New("trace shutdown failed")
+
+func TestTraceShutdown(t *testing.T) {
+	for _, tc := range []struct {
+		name string
+		exp  sdktrace.SpanExporter
+	}{
+		{
+			name: "deadline",
+			exp:  shutdownDeadlineExporter{},
+		},
+		{
+			name: "error",
+			exp:  shutdownErrorExporter{},
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			withTraceExporter(t, tc.name, tc.exp)
+
+			app := traceTestApp(t, nil)
+			require.NoError(t, app.Run(context.Background(), []string{"buildctl", "noop"}))
+		})
+	}
+}
+
+func TestTraceAfterError(t *testing.T) {
+	withTraceExporter(t, "noop", shutdownErrorExporter{})
+
+	errAfter := errors.New("after failed")
+	app := traceTestApp(t, func(context.Context, *cli.Command) error {
+		return errAfter
+	})
+	require.ErrorIs(t, app.Run(context.Background(), []string{"buildctl", "noop"}), errAfter)
+}
+
+func withTraceExporter(t *testing.T, name string, exp sdktrace.SpanExporter) {
+	t.Helper()
+
+	exporterName := "buildctl-common-test-" + name
+	detect.Register(exporterName, detect.TraceExporterDetector(func() (sdktrace.SpanExporter, error) {
+		return exp, nil
+	}), 0)
+	t.Setenv("OTEL_TRACES_EXPORTER", exporterName)
+}
+
+func traceTestApp(t *testing.T, after cli.AfterFunc) *cli.Command {
+	t.Helper()
+
+	app := &cli.Command{
+		Name:  "buildctl",
+		After: after,
+		Commands: []*cli.Command{
+			{
+				Name: "noop",
+				Action: func(context.Context, *cli.Command) error {
+					return nil
+				},
+			},
+		},
+	}
+	require.NoError(t, AttachAppContext(app))
+	return app
+}
+
+type shutdownDeadlineExporter struct{}
+
+func (shutdownDeadlineExporter) ExportSpans(context.Context, []sdktrace.ReadOnlySpan) error {
+	return nil
+}
+
+func (shutdownDeadlineExporter) Shutdown(ctx context.Context) error {
+	<-ctx.Done()
+	return context.Cause(ctx)
+}
+
+type shutdownErrorExporter struct{}
+
+func (shutdownErrorExporter) ExportSpans(context.Context, []sdktrace.ReadOnlySpan) error {
+	return nil
+}
+
+func (shutdownErrorExporter) Shutdown(context.Context) error {
+	return errTraceShutdown
+}