perf: several dragged items cross to another place as one tar stream; older agents get them one by one

internal/agent/shipmulti_test.go

@@ -0,0 +1,66 @@
+package agent
+
+import (
+	"archive/tar"
+	"bytes"
+	"context"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+// Several items of one folder go as one tar and land side by side; an entry
+// of none of them is refused.
+func TestShipSeveralInOneTar(t *testing.T) {
+	src, dst := t.TempDir(), t.TempDir()
+	_ = os.WriteFile(filepath.Join(src, "a.txt"), []byte("A"), 0o644)
+	_ = os.MkdirAll(filepath.Join(src, "b"), 0o755)
+	_ = os.WriteFile(filepath.Join(src, "b", "c.txt"), []byte("C"), 0o644)
+	var buf bytes.Buffer
+	items := []shipItem{{filepath.Join(src, "a.txt"), "a.txt"}, {filepath.Join(src, "b"), "b"}}
+	if err := packTars(context.Background(), &buf, items, &shipMeter{}); err != nil {
+		t.Fatal(err)
+	}
+	u := &unpacker{dir: dst, names: map[string]bool{"a.txt": true, "b": true}}
+	if err := u.unpack(tar.NewReader(&buf)); err != nil {
+		t.Fatal(err)
+	}
+	if b, _ := os.ReadFile(filepath.Join(dst, "b", "c.txt")); string(b) != "C" {
+		t.Fatalf("b/c.txt: %q", b)
+	}
+	if b, _ := os.ReadFile(filepath.Join(dst, "a.txt")); string(b) != "A" {
+		t.Fatalf("a.txt: %q", b)
+	}
+	buf.Reset()
+	_ = packTars(context.Background(), &buf, items, &shipMeter{})
+	u = &unpacker{dir: t.TempDir(), names: map[string]bool{"a.txt": true}}
+	if err := u.unpack(tar.NewReader(&buf)); err == nil || !strings.Contains(err.Error(), "чужой путь") {
+		t.Fatalf("b let in: %v", err)
+	}
+}
+
+func TestRenameTarSeveral(t *testing.T) {
+	var src bytes.Buffer
+	tw := tar.NewWriter(&src)
+	for _, n := range []string{"a", "b/x", "c", "._a"} {
+		_ = tw.WriteHeader(&tar.Header{Name: n, Mode: 0o644, Typeflag: tar.TypeReg})
+	}
+	_ = tw.Close()
+	var out bytes.Buffer
+	if err := renameTar(&out, &src, map[string]string{"a": "a", "b": "b2"}); err != nil {
+		t.Fatal(err)
+	}
+	tr := tar.NewReader(&out)
+	var got []string
+	for {
+		h, err := tr.Next()
+		if err != nil {
+			break
+		}
+		got = append(got, h.Name)
+	}
+	if strings.Join(got, ",") != "a,b2/x" {
+		t.Fatalf("entries: %v", got)
+	}
+}