commit 9e1d2601ac757a4318411aec96340be84ebf86ae (tree)
parent 756ebd4dc9a553feb1c16f3a0a83935e086cb0ed
Author: Motiejus Jakštys <motiejus@jakstys.lt>
Date: Mon, 24 May 2021 00:11:57 +0300
adding tests
Diffstat:
4 files changed, 68 insertions(+), 47 deletions(-)
diff --git a/BUILD b/BUILD
@@ -6,7 +6,7 @@ go_library(
importpath = "github.com/motiejus/code/undocker",
visibility = ["//visibility:private"],
deps = [
- "//src/undocker/rootfs:rootfs_lib",
+ "//src/undocker/rootfs:go_default_library",
"@com_github_jessevdk_go_flags//:go_default_library",
],
)
diff --git a/rootfs/BUILD b/rootfs/BUILD
@@ -1,10 +1,11 @@
load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
go_library(
- name = "rootfs_lib",
+ name = "go_default_library",
srcs = ["rootfs.go"],
importpath = "github.com/motiejus/code/undocker/rootfs",
visibility = ["//visibility:public"],
+ deps = ["@org_uber_go_multierr//:go_default_library"],
)
go_test(
diff --git a/rootfs/rootfs.go b/rootfs/rootfs.go
@@ -3,16 +3,24 @@ package rootfs
import (
"archive/tar"
"encoding/json"
+ "errors"
"io"
+ "path/filepath"
"strings"
+
+ "go.uber.org/multierr"
)
const (
_manifestJSON = "manifest.json"
)
+var (
+ ErrBadManifest = errors.New("bad or missing manifest.json")
+)
+
type dockerManifestJSON []struct {
- Config string `json:"Config"`
+ Config string `json:"Config,omitempty"`
Layers []string `json:"Layers"`
}
@@ -25,9 +33,12 @@ type dockerManifestJSON []struct {
// I) layer name
// II) offset (0 being the first file in the layer)
// 4. go through
-func RootFS(in io.ReadSeeker, out io.Writer) error {
+func RootFS(in io.ReadSeeker, out io.Writer) (err error) {
tr := tar.NewReader(in)
tw := tar.NewWriter(out)
+ defer func() {
+ err = multierr.Append(err, tw.Close())
+ }()
// layerOffsets maps a layer name (a9b123c0daa/layer.tar) to it's offset
layerOffsets := map[string]int64{}
@@ -46,7 +57,7 @@ func RootFS(in io.ReadSeeker, out io.Writer) error {
}
switch {
- case hdr.Name == _manifestJSON:
+ case filepath.Clean(hdr.Name) == _manifestJSON:
dec := json.NewDecoder(tr)
if err := dec.Decode(&manifest); err != nil {
return err
@@ -60,6 +71,10 @@ func RootFS(in io.ReadSeeker, out io.Writer) error {
}
}
+ if len(manifest) == 0 {
+ return ErrBadManifest
+ }
+
// phase 1.5: enumerate layers
layers := make([]int64, len(layerOffsets))
for i, name := range manifest[0].Layers {
@@ -136,5 +151,5 @@ func RootFS(in io.ReadSeeker, out io.Writer) error {
}
}
- return tw.Close()
+ return nil
}
diff --git a/rootfs/rootfs_test.go b/rootfs/rootfs_test.go
@@ -11,19 +11,23 @@ import (
"github.com/stretchr/testify/require"
)
-type layers []string
+type tarrable interface {
+ tar(*testing.T, *tar.Writer)
+}
-func (l layers) bytes() []byte {
- dockerManifest := dockerManifestJSON{{Layers: l}}
- b, err := json.Marshal(dockerManifest)
- if err != nil {
- panic("panic in a unit test")
- }
- return b
+type dir struct {
+ name string
+ uid int
}
-type tarrable interface {
- tar(*tar.Writer)
+func (d dir) tar(t *testing.T, tw *tar.Writer) {
+ t.Helper()
+ hdr := &tar.Header{
+ Typeflag: tar.TypeDir,
+ Name: d.name,
+ Uid: d.uid,
+ }
+ require.NoError(t, tw.WriteHeader(hdr))
}
type file struct {
@@ -32,31 +36,39 @@ type file struct {
contents []byte
}
-func (f file) tar(tw *tar.Writer) {
- hdr := &tar.Header{Typeflag: tar.TypeReg, Uid: f.uid}
- tw.WriteHeader(hdr)
- tw.Write(f.contents)
+func (f file) tar(t *testing.T, tw *tar.Writer) {
+ t.Helper()
+ hdr := &tar.Header{
+ Typeflag: tar.TypeReg,
+ Name: f.name,
+ Uid: f.uid,
+ Size: int64(len(f.contents)),
+ }
+ require.NoError(t, tw.WriteHeader(hdr))
+ _, err := tw.Write(f.contents)
+ require.NoError(t, err)
}
-type dir struct {
- name string
- uid int
-}
+type manifest []string
-func (f dir) tar(tw *tar.Writer) {
- hdr := &tar.Header{Typeflag: tar.TypeDir, Uid: f.uid}
- tw.WriteHeader(hdr)
+func (m manifest) tar(t *testing.T, tw *tar.Writer) {
+ t.Helper()
+ b, err := json.Marshal(dockerManifestJSON{{Layers: m}})
+ require.NoError(t, err)
+ file{name: "manifest.json", uid: 0, contents: b}.tar(t, tw)
}
type tarball []tarrable
-func (t tarball) bytes() []byte {
+func (tb tarball) bytes(t *testing.T) []byte {
+ t.Helper()
+
buf := bytes.Buffer{}
tw := tar.NewWriter(&buf)
- for _, member := range t {
- member.tar(tw)
+ for _, member := range tb {
+ member.tar(t, tw)
}
- tw.Close()
+ require.NoError(t, tw.Close())
return buf.Bytes()
}
@@ -81,28 +93,23 @@ func extract(t *testing.T, tarball io.Reader) []file {
return ret
}
-var (
- _layer0 = tarball{
+func TestRootFS(t *testing.T) {
+ _layer0 := tarball{
dir{name: "/", uid: 0},
file{name: "/file", uid: 1, contents: []byte("from 0")},
}
- _layer1 = tarball{
+ _layer1 := tarball{
dir{name: "/", uid: 1},
file{name: "/file", uid: 0, contents: []byte("from 1")},
}
- _image = tarball{
- file{name: "layer1/layer.tar", contents: _layer1.bytes()},
- file{name: "layer0/layer.tar", contents: _layer0.bytes()},
- file{
- name: "manifest.json",
- contents: layers{"layer0/layer.tar", "layer1/layer0.tar"}.bytes(),
- },
+ _image := tarball{
+ file{name: "layer1/layer.tar", contents: _layer1.bytes(t)},
+ file{name: "layer0/layer.tar", contents: _layer0.bytes(t)},
+ manifest{"layer0/layer0.tar", "layer1/layer.tar"},
}
-)
-func TestRootFS(t *testing.T) {
tests := []struct {
name string
image tarball
@@ -110,7 +117,7 @@ func TestRootFS(t *testing.T) {
}{
{
name: "empty",
- image: tarball{},
+ image: tarball{manifest{}},
want: []file{},
},
{
@@ -123,11 +130,9 @@ func TestRootFS(t *testing.T) {
},
}
- assert.Fail(t, "foo")
-
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
- in := bytes.NewReader(tt.image.bytes())
+ in := bytes.NewReader(tt.image.bytes(t))
out := bytes.Buffer{}
require.NoError(t, RootFS(in, &out))
