Merge pull request #143 from drassi-run/xfs-test

test `xfs.Read` and `xfs.Write` helper function

Author: dungdm93

core/util/fs/transfer.go

@@ -22,6 +22,15 @@ import (
 	"github.com/go-git/go-billy/v5/util"
 )
 
+// Read archives the directory or file at src within fsys into a tar stream and returns an io.ReadCloser.
+//
+// NOTE (Entry naming convention):
+//   - If src is "." or "", all files in fsys are archived relative to the root (e.g. "file.txt", "sub/file.txt").
+//   - If src is a directory (e.g. "app/config"), the base folder name is preserved in tar headers
+//     (e.g. "config/settings.json", "config/app.conf"), matching Docker container archive API behavior.
+//   - If src is a single file (e.g. "app/config/settings.json"), the tar entry name is the file's basename ("settings.json").
+//
+// docker cp logic: https://docs.docker.com/reference/cli/docker/container/cp/
 func Read(ctx context.Context, fsys billy.Filesystem, src string) io.ReadCloser {
 	reader, writer := io.Pipe()
 	go readPipe(ctx, fsys, src, writer)
@@ -60,10 +69,10 @@ func readPipe(ctx context.Context, fsys billy.Filesystem, src string, writer *io
 		var hdr *tar.Header
 		if hdr, err = tar.FileInfoHeader(info, link); err != nil {
 			return err
-		} else {
-			// info only contains file's base, but we want the path
-			hdr.Name = strings.TrimPrefix(path, dir)
 		}
+
+		// info only contains file's base, but we want the path
+		hdr.Name = strings.TrimPrefix(path, dir)
 		if err = tw.WriteHeader(hdr); err != nil {
 			return err
 		}
@@ -88,6 +97,7 @@ func readPipe(ctx context.Context, fsys billy.Filesystem, src string, writer *io
 	_ = writer.CloseWithError(err)
 }
 
+// Write extracts a tar archive from reader into the dest directory on fsys.
 func Write(ctx context.Context, fsys billy.Filesystem, reader io.Reader, dest string) error {
 	h := writeHandler(ctx, fsys, dest)
 	return xtar.Untar(ctx, reader, h)

core/util/fs/transfer_test.go

@@ -0,0 +1,222 @@
+/*
+ * SPDX-FileCopyrightText: (c) 2024 The Drassi Authors
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package xfs
+
+import (
+	"archive/tar"
+	"bytes"
+	"context"
+	"errors"
+	"io"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/go-git/go-billy/v5/osfs"
+	"github.com/stretchr/testify/require"
+)
+
+func assertTar(t *testing.T, r io.Reader, expectedEntries, expectedSymlinks map[string]string) {
+	t.Helper()
+	entries := make(map[string]string)
+	symlinks := make(map[string]string)
+	tr := tar.NewReader(r)
+
+	for {
+		hdr, err := tr.Next()
+		if errors.Is(err, io.EOF) {
+			break
+		}
+		require.NoError(t, err)
+
+		if hdr.Typeflag == tar.TypeSymlink {
+			symlinks[hdr.Name] = hdr.Linkname
+		} else if hdr.Typeflag == tar.TypeReg {
+			content, err := io.ReadAll(tr)
+			require.NoError(t, err)
+			entries[hdr.Name] = string(content)
+		}
+	}
+
+	if expectedEntries != nil {
+		require.Equal(t, expectedEntries, entries)
+	} else {
+		require.Empty(t, entries)
+	}
+
+	if expectedSymlinks != nil {
+		require.Equal(t, expectedSymlinks, symlinks)
+	} else {
+		require.Empty(t, symlinks)
+	}
+}
+
+func TestRead(t *testing.T) {
+	t.Run("root directory", func(t *testing.T) {
+		tempDir := t.TempDir()
+		require.NoError(t, os.WriteFile(filepath.Join(tempDir, "file1.txt"), []byte("content1"), 0o644))
+		require.NoError(t, os.MkdirAll(filepath.Join(tempDir, "sub"), 0o755))
+		require.NoError(t, os.WriteFile(filepath.Join(tempDir, "sub", "file2.txt"), []byte("content2"), 0o644))
+		require.NoError(t, os.Symlink("file1.txt", filepath.Join(tempDir, "link1")))
+
+		fsys := osfs.New(tempDir)
+		rc := Read(t.Context(), fsys, ".")
+		defer rc.Close()
+
+		entries := map[string]string{
+			"file1.txt":     "content1",
+			"sub/file2.txt": "content2",
+		}
+		symlinks := map[string]string{
+			"link1": "file1.txt",
+		}
+		assertTar(t, rc, entries, symlinks)
+	})
+
+	t.Run("subpath directory preserves folder name", func(t *testing.T) {
+		tempDir := t.TempDir()
+		appConfigDir := filepath.Join(tempDir, "app", "config")
+		require.NoError(t, os.MkdirAll(appConfigDir, 0o755))
+		require.NoError(t, os.WriteFile(filepath.Join(appConfigDir, "settings.json"), []byte(`{"port":8080}`), 0o644))
+		require.NoError(t, os.WriteFile(filepath.Join(appConfigDir, "app.conf"), []byte("key=val"), 0o644))
+
+		fsys := osfs.New(tempDir)
+		rc := Read(t.Context(), fsys, "app/config")
+		defer rc.Close()
+
+		entries := map[string]string{
+			"config/settings.json": `{"port":8080}`,
+			"config/app.conf":      "key=val",
+		}
+		assertTar(t, rc, entries, nil)
+	})
+
+	t.Run("single file subpath", func(t *testing.T) {
+		tempDir := t.TempDir()
+		appDir := filepath.Join(tempDir, "app")
+		require.NoError(t, os.MkdirAll(appDir, 0o755))
+		require.NoError(t, os.WriteFile(filepath.Join(appDir, "config.yaml"), []byte("env: test"), 0o644))
+
+		fsys := osfs.New(tempDir)
+		rc := Read(t.Context(), fsys, "app/config.yaml")
+		defer rc.Close()
+
+		entries := map[string]string{
+			"config.yaml": "env: test",
+		}
+		assertTar(t, rc, entries, nil)
+	})
+
+	t.Run("context cancellation stops read", func(t *testing.T) {
+		tempDir := t.TempDir()
+		require.NoError(t, os.WriteFile(filepath.Join(tempDir, "file.txt"), []byte("data"), 0o644))
+
+		ctx, cancel := context.WithCancel(t.Context())
+		cancel()
+
+		fsys := osfs.New(tempDir)
+		rc := Read(ctx, fsys, ".")
+		defer rc.Close()
+
+		_, err := io.ReadAll(rc)
+		require.Error(t, err)
+		require.True(t, errors.Is(err, context.Canceled) || errors.Is(err, io.ErrClosedPipe))
+	})
+}
+
+func TestWrite(t *testing.T) {
+	t.Run("extracts directory structure regular files and symlinks", func(t *testing.T) {
+		destDir := t.TempDir()
+		destFsys := osfs.New(destDir)
+
+		buf := new(bytes.Buffer)
+		tw := tar.NewWriter(buf)
+
+		// Directory entry
+		require.NoError(t, tw.WriteHeader(&tar.Header{
+			Name:     "extracted/sub/",
+			Typeflag: tar.TypeDir,
+			Mode:     0o755,
+		}))
+
+		// Regular file entry
+		fileContent := []byte("hello extracted")
+		require.NoError(t, tw.WriteHeader(&tar.Header{
+			Name:     "extracted/sub/file.txt",
+			Typeflag: tar.TypeReg,
+			Mode:     0o644,
+			Size:     int64(len(fileContent)),
+		}))
+		_, err := tw.Write(fileContent)
+		require.NoError(t, err)
+
+		// Symlink entry
+		require.NoError(t, tw.WriteHeader(&tar.Header{
+			Name:     "extracted/sub/link.txt",
+			Typeflag: tar.TypeSymlink,
+			Linkname: "file.txt",
+		}))
+		require.NoError(t, tw.Close())
+
+		err = Write(t.Context(), destFsys, buf, "")
+		require.NoError(t, err)
+
+		// Verify extracted files on disk
+		content, err := os.ReadFile(filepath.Join(destDir, "extracted", "sub", "file.txt"))
+		require.NoError(t, err)
+		require.Equal(t, "hello extracted", string(content))
+
+		target, err := os.Readlink(filepath.Join(destDir, "extracted", "sub", "link.txt"))
+		require.NoError(t, err)
+		require.Equal(t, "file.txt", target)
+	})
+
+	t.Run("unsupported entry type returns error", func(t *testing.T) {
+		destDir := t.TempDir()
+		destFsys := osfs.New(destDir)
+
+		buf := new(bytes.Buffer)
+		tw := tar.NewWriter(buf)
+
+		require.NoError(t, tw.WriteHeader(&tar.Header{
+			Name:     "fifo_pipe",
+			Typeflag: tar.TypeFifo,
+		}))
+		require.NoError(t, tw.Close())
+
+		err := Write(t.Context(), destFsys, buf, "")
+		require.Error(t, err)
+		require.Contains(t, err.Error(), "unsupported fifo file")
+	})
+}
+
+func TestReadWriteRoundTrip(t *testing.T) {
+	srcDir := t.TempDir()
+	destDir := t.TempDir()
+
+	require.NoError(t, os.MkdirAll(filepath.Join(srcDir, "nested", "dir"), 0o755))
+	require.NoError(t, os.WriteFile(filepath.Join(srcDir, "nested", "file.txt"), []byte("payload data"), 0o644))
+	require.NoError(t, os.Symlink("file.txt", filepath.Join(srcDir, "nested", "symlink.txt")))
+
+	srcFsys := osfs.New(srcDir)
+	destFsys := osfs.New(destDir)
+
+	rc := Read(t.Context(), srcFsys, "nested")
+	defer rc.Close()
+
+	err := Write(t.Context(), destFsys, rc, "target")
+	require.NoError(t, err)
+
+	extractedFile := filepath.Join(destDir, "target", "nested", "file.txt")
+	content, err := os.ReadFile(extractedFile)
+	require.NoError(t, err)
+	require.Equal(t, "payload data", string(content))
+
+	linkTarget, err := os.Readlink(filepath.Join(destDir, "target", "nested", "symlink.txt"))
+	require.NoError(t, err)
+	require.Equal(t, "file.txt", linkTarget)
+}