internal/pkg: tar optional file

This allows tar to take a single-file directory Artifact as input.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/pkg/dir_test.go

@@ -209,6 +209,7 @@ func TestFlatten(t *testing.T) {
 
 			"identifier": {Mode: fs.ModeDir | 0700},
 			"identifier/-P_1iw6yVq_letMHncqcExSE0bYcDhYI5OdY6b1wKASf-Corufvj__XTBUq2Qd2a": {Mode: fs.ModeSymlink | 0777, Data: []byte("../checksum/cTw0h3AmYe7XudSoyEMByduYXqGi-N5ZkTZ0t9K5elsu3i_jNIVF5T08KR1roBFM")},
+			"identifier/0_rRxIqbX9LK9L_KDbuafotFz6HFkonNgO9gXhK1asM_Y1Pxn0amg756vRTo6m74": {Mode: fs.ModeSymlink | 0777, Data: []byte("../checksum/cTw0h3AmYe7XudSoyEMByduYXqGi-N5ZkTZ0t9K5elsu3i_jNIVF5T08KR1roBFM")},
 
 			"temp": {Mode: fs.ModeDir | 0700},
 			"work": {Mode: fs.ModeDir | 0700},
@@ -230,10 +231,11 @@ func TestFlatten(t *testing.T) {
 
 			{Mode: fs.ModeDir | 0700, Path: "identifier"},
 			{Mode: fs.ModeSymlink | 0777, Path: "identifier/-P_1iw6yVq_letMHncqcExSE0bYcDhYI5OdY6b1wKASf-Corufvj__XTBUq2Qd2a", Data: []byte("../checksum/cTw0h3AmYe7XudSoyEMByduYXqGi-N5ZkTZ0t9K5elsu3i_jNIVF5T08KR1roBFM")},
+			{Mode: fs.ModeSymlink | 0777, Path: "identifier/0_rRxIqbX9LK9L_KDbuafotFz6HFkonNgO9gXhK1asM_Y1Pxn0amg756vRTo6m74", Data: []byte("../checksum/cTw0h3AmYe7XudSoyEMByduYXqGi-N5ZkTZ0t9K5elsu3i_jNIVF5T08KR1roBFM")},
 
 			{Mode: fs.ModeDir | 0700, Path: "temp"},
 			{Mode: fs.ModeDir | 0700, Path: "work"},
-		}, pkg.MustDecode("PrNWkHqtSmdtVecctlI9Xf63dQPIyyLBIMCtRAP2-VqF9u1oQ8ydV7-WPbzEvMkG"), nil},
+		}, pkg.MustDecode("sxbgyX-bPoezbha214n2lbQhiVfTUBkhZ0EX6zI7mmkMdrCdwuMwhMBJphLQsy94"), nil},
 
 		{"sample tar expand step unpack", fstest.MapFS{
 			".": {Mode: fs.ModeDir | 0500},
@@ -254,6 +256,7 @@ func TestFlatten(t *testing.T) {
 
 			"identifier": {Mode: fs.ModeDir | 0700},
 			"identifier/-P_1iw6yVq_letMHncqcExSE0bYcDhYI5OdY6b1wKASf-Corufvj__XTBUq2Qd2a": {Mode: fs.ModeSymlink | 0777, Data: []byte("../checksum/CH3AiUrCCcVOjOYLaMKKK1Da78989JtfHeIsxMzWOQFiN4mrCLDYpoDxLWqJWCUN")},
+			"identifier/0_rRxIqbX9LK9L_KDbuafotFz6HFkonNgO9gXhK1asM_Y1Pxn0amg756vRTo6m74": {Mode: fs.ModeSymlink | 0777, Data: []byte("../checksum/CH3AiUrCCcVOjOYLaMKKK1Da78989JtfHeIsxMzWOQFiN4mrCLDYpoDxLWqJWCUN")},
 
 			"temp": {Mode: fs.ModeDir | 0700},
 			"work": {Mode: fs.ModeDir | 0700},
@@ -266,10 +269,11 @@ func TestFlatten(t *testing.T) {
 
 			{Mode: fs.ModeDir | 0700, Path: "identifier"},
 			{Mode: fs.ModeSymlink | 0777, Path: "identifier/-P_1iw6yVq_letMHncqcExSE0bYcDhYI5OdY6b1wKASf-Corufvj__XTBUq2Qd2a", Data: []byte("../checksum/CH3AiUrCCcVOjOYLaMKKK1Da78989JtfHeIsxMzWOQFiN4mrCLDYpoDxLWqJWCUN")},
+			{Mode: fs.ModeSymlink | 0777, Path: "identifier/0_rRxIqbX9LK9L_KDbuafotFz6HFkonNgO9gXhK1asM_Y1Pxn0amg756vRTo6m74", Data: []byte("../checksum/CH3AiUrCCcVOjOYLaMKKK1Da78989JtfHeIsxMzWOQFiN4mrCLDYpoDxLWqJWCUN")},
 
 			{Mode: fs.ModeDir | 0700, Path: "temp"},
 			{Mode: fs.ModeDir | 0700, Path: "work"},
-		}, pkg.MustDecode("YZUoGdMwmfW5sQWto9hQgMKah648rHKck8Ds_GGnqgCBpTAiZKOefpHCKnvktfYh"), nil},
+		}, pkg.MustDecode("4I8wx_h7NSJTlG5lbuz-GGEXrOg0GYC3M_503LYEBhv5XGWXfNIdIY9Q3eVSYldX"), nil},
 
 		{"testtool", fstest.MapFS{
 			".": {Mode: fs.ModeDir | 0500},

internal/pkg/exec_test.go

@@ -300,26 +300,6 @@ func newTesttool() (
 			).String(), testtoolBin, 0500)
 		},
 	}}
-	testtoolDestroy = func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
-		if pathname, checksum, err := c.Cure(testtool); err != nil {
-			t.Fatalf("Cure: error = %v", err)
-		} else if err = os.Remove(pathname.String()); err != nil {
-			t.Fatal(err)
-		} else {
-			p := base.Append(
-				"checksum",
-				pkg.Encode(checksum),
-			)
-			if err = os.Chmod(p.Append("bin").String(), 0700); err != nil {
-				t.Fatal(err)
-			}
-			if err = os.Chmod(p.String(), 0700); err != nil {
-				t.Fatal(err)
-			}
-			if err = os.RemoveAll(p.String()); err != nil {
-				t.Fatal(err)
-			}
-		}
-	}
+	testtoolDestroy = newDestroyArtifactFunc(testtool)
 	return
 }

internal/pkg/pkg_test.go

@@ -117,6 +117,59 @@ func newStubFile(
 	}
 }
 
+// destroyArtifact removes all traces of an [Artifact] from the on-disk cache.
+// Do not use this in a test case without a very good reason to do so.
+func destroyArtifact(
+	t *testing.T,
+	base *check.Absolute,
+	c *pkg.Cache,
+	a pkg.Artifact,
+) {
+	if pathname, checksum, err := c.Cure(a); err != nil {
+		t.Fatalf("Cure: error = %v", err)
+	} else if err = os.Remove(pathname.String()); err != nil {
+		t.Fatal(err)
+	} else {
+		p := base.Append(
+			"checksum",
+			pkg.Encode(checksum),
+		)
+		if err = filepath.WalkDir(p.String(), func(
+			path string,
+			d fs.DirEntry,
+			err error,
+		) error {
+			if err != nil {
+				return err
+			}
+			if d.IsDir() {
+				return os.Chmod(path, 0700)
+			}
+			return nil
+		}); err != nil && !errors.Is(err, os.ErrNotExist) {
+			t.Fatal(err)
+		}
+		if err = os.RemoveAll(p.String()); err != nil {
+			t.Fatal(err)
+		}
+	}
+}
+
+// newDestroyArtifactFunc returns a function that calls destroyArtifact.
+func newDestroyArtifactFunc(a pkg.Artifact) func(
+	t *testing.T,
+	base *check.Absolute,
+	c *pkg.Cache,
+) {
+	return func(
+		t *testing.T,
+		base *check.Absolute,
+		c *pkg.Cache,
+	) {
+		destroyArtifact(t, base, c, a)
+	}
+}
+
 func TestIdent(t *testing.T) {
 	t.Parallel()
 

internal/pkg/tar.go

@@ -28,15 +28,17 @@ const (
 // A tarArtifact is an [Artifact] unpacking a tarball backed by a [File].
 type tarArtifact struct {
 	// Caller-supplied backing tarball.
-	f File
+	f Artifact
 	// Compression on top of the tarball.
 	compression uint64
 }
 
-// NewTar returns a new [Artifact] backed by the supplied [File] and
-// compression method.
-func NewTar(f File, compression uint64) Artifact {
-	return &tarArtifact{f: f, compression: compression}
+// NewTar returns a new [Artifact] backed by the supplied [Artifact] and
+// compression method. If f implements [File], its data might be used directly,
+// eliminating the roundtrip to vfs. If f is a directory, it must contain a
+// single regular file.
+func NewTar(a Artifact, compression uint64) Artifact {
+	return &tarArtifact{a, compression}
 }
 
 // NewHTTPGetTar is abbreviation for NewHTTPGet passed to NewTar.
@@ -76,26 +78,46 @@ func (a *tarArtifact) Cure(c *CureContext) (err error) {
 	temp := c.GetTempDir()
 	var tr io.ReadCloser
 
-	{
-
-		if tr, err = c.OpenFile(a.f); err != nil {
+	if file, ok := a.f.(File); ok {
+		if tr, err = c.OpenFile(file); err != nil {
+			return
+		}
+	} else {
+		var pathname *check.Absolute
+		if pathname, _, err = c.Cure(a.f); err != nil {
+			return
+		}
+
+		var entries []os.DirEntry
+		if entries, err = os.ReadDir(pathname.String()); err != nil {
+			return
+		}
+
+		if len(entries) != 1 || !entries[0].Type().IsRegular() {
+			return errors.New(
+				"input directory does not contain a single regular file",
+			)
+		} else {
+			pathname = pathname.Append(entries[0].Name())
+		}
+
+		if tr, err = os.Open(pathname.String()); err != nil {
 			return
 		}
-		defer func(f io.ReadCloser) {
-			closeErr := f.Close()
-			if err == nil {
-				err = closeErr
-			}
-		}(tr)
-		tr = io.NopCloser(tr)
 	}
 
-	defer func() {
+	defer func(f io.ReadCloser) {
 		closeErr := tr.Close()
 		if err == nil {
 			err = closeErr
 		}
-	}()
+
+		closeErr = f.Close()
+		if err == nil {
+			err = closeErr
+		}
+	}(tr)
+	tr = io.NopCloser(tr)
 
 	switch a.compression {
 	case TarUncompressed:

internal/pkg/tar_test.go

@@ -5,12 +5,15 @@ import (
 	"bytes"
 	"compress/gzip"
 	"crypto/sha512"
+	"errors"
 	"io/fs"
 	"net/http"
+	"os"
 	"testing"
 	"testing/fstest"
 
 	"hakurei.app/container/check"
+	"hakurei.app/container/stub"
 	"hakurei.app/internal/pkg"
 )
 
@@ -37,7 +40,7 @@ func TestTar(t *testing.T) {
 			}, pkg.MustDecode(
 				"cTw0h3AmYe7XudSoyEMByduYXqGi-N5ZkTZ0t9K5elsu3i_jNIVF5T08KR1roBFM",
 			))
-		}, pkg.MustDecode("PrNWkHqtSmdtVecctlI9Xf63dQPIyyLBIMCtRAP2-VqF9u1oQ8ydV7-WPbzEvMkG")},
+		}, pkg.MustDecode("sxbgyX-bPoezbha214n2lbQhiVfTUBkhZ0EX6zI7mmkMdrCdwuMwhMBJphLQsy94")},
 
 		{"http expand", nil, func(t *testing.T, base *check.Absolute, c *pkg.Cache) {
 			checkTarHTTP(t, base, c, fstest.MapFS{
@@ -48,7 +51,7 @@ func TestTar(t *testing.T) {
 			}, pkg.MustDecode(
 				"CH3AiUrCCcVOjOYLaMKKK1Da78989JtfHeIsxMzWOQFiN4mrCLDYpoDxLWqJWCUN",
 			))
-		}, pkg.MustDecode("YZUoGdMwmfW5sQWto9hQgMKah648rHKck8Ds_GGnqgCBpTAiZKOefpHCKnvktfYh")},
+		}, pkg.MustDecode("4I8wx_h7NSJTlG5lbuz-GGEXrOg0GYC3M_503LYEBhv5XGWXfNIdIY9Q3eVSYldX")},
 	})
 }
 
@@ -115,18 +118,88 @@ func checkTarHTTP(
 		t.Fatalf("Ident: %s, want %s", pkg.Encode(id), pkg.Encode(wantIdent))
 	}
 
-	wantPathname := base.Append(
-		"identifier",
-		pkg.Encode(wantIdent),
-	)
-	if pathname, checksum, err := c.Cure(a); err != nil {
-		t.Fatalf("Cure: error = %v", err)
-	} else if !pathname.Is(wantPathname) {
-		t.Fatalf("Cure: %q, want %q", pathname, wantPathname)
-	} else if checksum != wantChecksum {
-		t.Fatalf("Cure: %v", &pkg.ChecksumMismatchError{
-			Got:  checksum,
-			Want: wantChecksum,
-		})
+	tarDir := stubArtifact{
+		kind:   pkg.KindExec,
+		params: []byte("directory containing a single regular file"),
+		cure: func(c *pkg.CureContext) error {
+			work := c.GetWorkDir()
+			if err := os.MkdirAll(work.String(), 0700); err != nil {
+				return err
+			}
+			return os.WriteFile(
+				work.Append("sample.tar.gz").String(),
+				[]byte(testdata),
+				0400,
+			)
+		},
 	}
+	tarDirMulti := stubArtifact{
+		kind:   pkg.KindExec,
+		params: []byte("directory containing a multiple entries"),
+		cure: func(c *pkg.CureContext) error {
+			work := c.GetWorkDir()
+			if err := os.MkdirAll(work.Append(
+				"garbage",
+			).String(), 0700); err != nil {
+				return err
+			}
+			return os.WriteFile(
+				work.Append("sample.tar.gz").String(),
+				[]byte(testdata),
+				0400,
+			)
+		},
+	}
+	tarDirType := stubArtifact{
+		kind:   pkg.KindExec,
+		params: []byte("directory containing a symbolic link"),
+		cure: func(c *pkg.CureContext) error {
+			work := c.GetWorkDir()
+			if err := os.MkdirAll(work.String(), 0700); err != nil {
+				return err
+			}
+			return os.Symlink(
+				work.String(),
+				work.Append("sample.tar.gz").String(),
+			)
+		},
+	}
+	// destroy these to avoid including it in flatten test case
+	defer newDestroyArtifactFunc(tarDir)(t, base, c)
+	defer newDestroyArtifactFunc(tarDirMulti)(t, base, c)
+	defer newDestroyArtifactFunc(tarDirType)(t, base, c)
+
+	cureMany(t, c, []cureStep{
+		{"file", a, base.Append(
+			"identifier",
+			pkg.Encode(wantIdent),
+		), wantChecksum, nil},
+
+		{"directory", pkg.NewTar(
+			tarDir,
+			pkg.TarGzip,
+		), ignorePathname, wantChecksum, nil},
+
+		{"multiple entries", pkg.NewTar(
+			tarDirMulti,
+			pkg.TarGzip,
+		), nil, pkg.Checksum{}, errors.New(
+			"input directory does not contain a single regular file",
+		)},
+
+		{"bad type", pkg.NewTar(
+			tarDirType,
+			pkg.TarGzip,
+		), nil, pkg.Checksum{}, errors.New(
+			"input directory does not contain a single regular file",
+		)},
+
+		{"error passthrough", pkg.NewTar(stubArtifact{
+			kind:   pkg.KindExec,
+			params: []byte("doomed artifact"),
+			cure: func(c *pkg.CureContext) error {
+				return stub.UniqueError(0xcafe)
+			},
+		}, pkg.TarGzip), nil, pkg.Checksum{}, stub.UniqueError(0xcafe)},
+	})
 }