commit e2cf760c1214c7a4594dbd1ec49c4fabec2e54b8 (tree)
parent e1555f31a8fd9e929c1dddafc2cf713785d6f5d9
Author: Motiejus Jakštys <motiejus@jakstys.lt>
Date: Mon, 24 May 2021 00:11:58 +0300
remove ByteCounter from rootfs
Diffstat:
4 files changed, 29 insertions(+), 31 deletions(-)
diff --git a/internal/cmdrootfs/cmdrootfs.go b/internal/cmdrootfs/cmdrootfs.go
@@ -13,7 +13,11 @@ import (
)
type (
- rootfsFactory func(io.ReadSeeker) io.WriterTo
+ flattener interface {
+ Flatten(io.Writer) error
+ }
+
+ rootfsFactory func(io.ReadSeeker) flattener
// Command is "rootfs" command
Command struct {
@@ -55,10 +59,7 @@ func (c *Command) Execute(args []string) (err error) {
out = outf
}
- if _, err := c.rootfsNew(rd).WriteTo(out); err != nil {
- return err
- }
- return nil
+ return c.rootfsNew(rd).Flatten(out)
}
// init() initializes Command with the default options.
@@ -67,7 +68,7 @@ func (c *Command) Execute(args []string) (err error) {
// command will initialize itself.
func (c *Command) init() {
c.BaseCommand.Init()
- c.rootfsNew = func(r io.ReadSeeker) io.WriterTo {
+ c.rootfsNew = func(r io.ReadSeeker) flattener {
return rootfs.New(r)
}
}
diff --git a/internal/cmdrootfs/cmdrootfs_test.go b/internal/cmdrootfs/cmdrootfs_test.go
@@ -67,7 +67,7 @@ func TestExecute(t *testing.T) {
inf := filepath.Join(dir, tt.infile)
c.PositionalArgs.Infile = goflags.Filename(inf)
c.PositionalArgs.Outfile = tt.outfile
- c.rootfsNew = func(r io.ReadSeeker) io.WriterTo {
+ c.rootfsNew = func(r io.ReadSeeker) flattener {
return &passthrough{r}
}
@@ -92,4 +92,7 @@ func TestExecute(t *testing.T) {
type passthrough struct{ r io.Reader }
-func (p *passthrough) WriteTo(w io.Writer) (int64, error) { return io.Copy(w, p.r) }
+func (p *passthrough) Flatten(w io.Writer) error {
+ _, err := io.Copy(w, p.r)
+ return err
+}
diff --git a/rootfs/rootfs.go b/rootfs/rootfs.go
@@ -12,7 +12,6 @@ import (
"path/filepath"
"strings"
- "github.com/motiejus/code/undocker/internal/bytecounter"
"go.uber.org/multierr"
)
@@ -48,8 +47,8 @@ func New(rd io.ReadSeeker) *RootFS {
return &RootFS{rd: rd}
}
-// WriteTo writes a docker image to an open tarball.
-func (r *RootFS) WriteTo(w io.Writer) (n int64, err error) {
+// Flatten flattens a docker image to an open tarball.
+func (r *RootFS) Flatten(w io.Writer) (err error) {
tr := tar.NewReader(r.rd)
var closer func() error
@@ -72,19 +71,19 @@ func (r *RootFS) WriteTo(w io.Writer) (n int64, err error) {
case filepath.Clean(hdr.Name) == _manifestJSON:
dec := json.NewDecoder(tr)
if err := dec.Decode(&manifest); err != nil {
- return n, fmt.Errorf("decode %s: %w", _manifestJSON, err)
+ return fmt.Errorf("decode %s: %w", _manifestJSON, err)
}
case strings.HasSuffix(hdr.Name, _layerSuffix):
here, err := r.rd.Seek(0, io.SeekCurrent)
if err != nil {
- return n, err
+ return err
}
layerOffsets[hdr.Name] = here
}
}
if len(manifest) == 0 || len(layerOffsets) != len(manifest[0].Layers) {
- return n, errBadManifest
+ return errBadManifest
}
// enumerate layers the way they would be laid down in the image
@@ -109,7 +108,7 @@ func (r *RootFS) WriteTo(w io.Writer) (n int64, err error) {
// iterate over all files, construct `file2layer`, `whreaddir`, `wh`
for i, no := range layers {
if _, err := r.rd.Seek(no.offset, io.SeekStart); err != nil {
- return n, err
+ return err
}
tr, closer = openTargz(r.rd)
for {
@@ -118,7 +117,7 @@ func (r *RootFS) WriteTo(w io.Writer) (n int64, err error) {
break
}
if err != nil {
- return n, fmt.Errorf("decode %s: %w", no.name, err)
+ return fmt.Errorf("decode %s: %w", no.name, err)
}
if hdr.Typeflag == tar.TypeDir {
continue
@@ -142,23 +141,21 @@ func (r *RootFS) WriteTo(w io.Writer) (n int64, err error) {
file2layer[hdr.Name] = i
}
if err := closer(); err != nil {
- return n, err
+ return err
}
}
// construct directories to whiteout, for each layer.
whIgnore := whiteoutDirs(whreaddir, len(layers))
- wr := bytecounter.New(w)
- tw := tar.NewWriter(wr)
+ tw := tar.NewWriter(w)
defer func() {
err = multierr.Append(err, tw.Close())
- n = wr.N
}()
// iterate through all layers, all files, and write files.
for i, no := range layers {
if _, err := r.rd.Seek(no.offset, io.SeekStart); err != nil {
- return n, err
+ return err
}
tr, closer = openTargz(r.rd)
for {
@@ -167,7 +164,7 @@ func (r *RootFS) WriteTo(w io.Writer) (n int64, err error) {
break
}
if err != nil {
- return n, fmt.Errorf("decode %s: %w", no.name, err)
+ return fmt.Errorf("decode %s: %w", no.name, err)
}
if layer, ok := wh[hdr.Name]; ok && layer >= i {
continue
@@ -179,14 +176,14 @@ func (r *RootFS) WriteTo(w io.Writer) (n int64, err error) {
continue
}
if err := writeFile(tr, tw, hdr); err != nil {
- return n, err
+ return err
}
}
if err := closer(); err != nil {
- return n, err
+ return err
}
}
- return n, nil
+ return nil
}
func writeFile(tr *tar.Reader, tw *tar.Writer, hdr *tar.Header) error {
@@ -238,10 +235,8 @@ func whiteoutDirs(whreaddir map[string]int, nlayers int) []*tree {
// openTargz creates a tar reader from a targzip or tar.
//
-// We may be looking at magic values for tar and/or gzip,
-// which would mean "cleaner" code (e.g. no proxyWriter),
-// but that would mean re-implementing gzip.readHeader(),
-// which is ... already in stdlib.
+// It will try to open a gzip stream, and, if that fails, silently fall back to
+// tar. I will accept a cleaner implementation looking at magic values.
func openTargz(r io.Reader) (*tar.Reader, func() error) {
hdrbuf := &bytes.Buffer{}
hdrw := &proxyWriter{w: hdrbuf}
diff --git a/rootfs/rootfs_test.go b/rootfs/rootfs_test.go
@@ -186,7 +186,7 @@ func TestRootFS(t *testing.T) {
in := bytes.NewReader(tt.image.Buffer().Bytes())
out := bytes.Buffer{}
- n, err := New(in).WriteTo(&out)
+ err := New(in).Flatten(&out)
if tt.wantErr != "" {
assert.EqualError(t, err, tt.wantErr)
return
@@ -195,7 +195,6 @@ func TestRootFS(t *testing.T) {
require.NoError(t, err)
got := tartest.Extract(t, bytes.NewReader(outb))
assert.Equal(t, tt.want, got)
- assert.Equal(t, int64(len(outb)), n)
})
}
}
