1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
/*
Copyright The containerd Authors.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
package walking
import (
"context"
"encoding/base64"
"fmt"
"io"
"math/rand"
"time"
"github.com/containerd/containerd/archive"
"github.com/containerd/containerd/archive/compression"
"github.com/containerd/containerd/content"
"github.com/containerd/containerd/diff"
"github.com/containerd/containerd/errdefs"
"github.com/containerd/containerd/log"
"github.com/containerd/containerd/mount"
digest "github.com/opencontainers/go-digest"
ocispec "github.com/opencontainers/image-spec/specs-go/v1"
"github.com/pkg/errors"
)
type walkingDiff struct {
store content.Store
}
var emptyDesc = ocispec.Descriptor{}
var uncompressed = "containerd.io/uncompressed"
// NewWalkingDiff is a generic implementation of diff.Comparer. The diff is
// calculated by mounting both the upper and lower mount sets and walking the
// mounted directories concurrently. Changes are calculated by comparing files
// against each other or by comparing file existence between directories.
// NewWalkingDiff uses no special characteristics of the mount sets and is
// expected to work with any filesystem.
func NewWalkingDiff(store content.Store) diff.Comparer {
return &walkingDiff{
store: store,
}
}
// Compare creates a diff between the given mounts and uploads the result
// to the content store.
func (s *walkingDiff) Compare(ctx context.Context, lower, upper []mount.Mount, opts ...diff.Opt) (d ocispec.Descriptor, err error) {
var config diff.Config
for _, opt := range opts {
if err := opt(&config); err != nil {
return emptyDesc, err
}
}
if config.MediaType == "" {
config.MediaType = ocispec.MediaTypeImageLayerGzip
}
var isCompressed bool
switch config.MediaType {
case ocispec.MediaTypeImageLayer:
case ocispec.MediaTypeImageLayerGzip:
isCompressed = true
default:
return emptyDesc, errors.Wrapf(errdefs.ErrNotImplemented, "unsupported diff media type: %v", config.MediaType)
}
var ocidesc ocispec.Descriptor
if err := mount.WithTempMount(ctx, lower, func(lowerRoot string) error {
return mount.WithTempMount(ctx, upper, func(upperRoot string) error {
var newReference bool
if config.Reference == "" {
newReference = true
config.Reference = uniqueRef()
}
cw, err := s.store.Writer(ctx,
content.WithRef(config.Reference),
content.WithDescriptor(ocispec.Descriptor{
MediaType: config.MediaType, // most contentstore implementations just ignore this
}))
if err != nil {
return errors.Wrap(err, "failed to open writer")
}
defer func() {
if err != nil {
cw.Close()
if newReference {
if err := s.store.Abort(ctx, config.Reference); err != nil {
log.G(ctx).WithField("ref", config.Reference).Warnf("failed to delete diff upload")
}
}
}
}()
if !newReference {
if err = cw.Truncate(0); err != nil {
return err
}
}
if isCompressed {
dgstr := digest.SHA256.Digester()
var compressed io.WriteCloser
compressed, err = compression.CompressStream(cw, compression.Gzip)
if err != nil {
return errors.Wrap(err, "failed to get compressed stream")
}
err = archive.WriteDiff(ctx, io.MultiWriter(compressed, dgstr.Hash()), lowerRoot, upperRoot)
compressed.Close()
if err != nil {
return errors.Wrap(err, "failed to write compressed diff")
}
if config.Labels == nil {
config.Labels = map[string]string{}
}
config.Labels[uncompressed] = dgstr.Digest().String()
} else {
if err = archive.WriteDiff(ctx, cw, lowerRoot, upperRoot); err != nil {
return errors.Wrap(err, "failed to write diff")
}
}
var commitopts []content.Opt
if config.Labels != nil {
commitopts = append(commitopts, content.WithLabels(config.Labels))
}
dgst := cw.Digest()
if err := cw.Commit(ctx, 0, dgst, commitopts...); err != nil {
if !errdefs.IsAlreadyExists(err) {
return errors.Wrap(err, "failed to commit")
}
}
info, err := s.store.Info(ctx, dgst)
if err != nil {
return errors.Wrap(err, "failed to get info from content store")
}
if info.Labels == nil {
info.Labels = make(map[string]string)
}
// Set uncompressed label if digest already existed without label
if _, ok := info.Labels[uncompressed]; !ok {
info.Labels[uncompressed] = config.Labels[uncompressed]
if _, err := s.store.Update(ctx, info, "labels."+uncompressed); err != nil {
return errors.Wrap(err, "error setting uncompressed label")
}
}
ocidesc = ocispec.Descriptor{
MediaType: config.MediaType,
Size: info.Size,
Digest: info.Digest,
}
return nil
})
}); err != nil {
return emptyDesc, err
}
return ocidesc, nil
}
func uniqueRef() string {
t := time.Now()
var b [3]byte
// Ignore read failures, just decreases uniqueness
rand.Read(b[:])
return fmt.Sprintf("%d-%s", t.UnixNano(), base64.URLEncoding.EncodeToString(b[:]))
}
|
