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
|
package layer // import "github.com/docker/docker/layer"
import (
"fmt"
"io"
"github.com/docker/distribution"
"github.com/opencontainers/go-digest"
)
type roLayer struct {
chainID ChainID
diffID DiffID
parent *roLayer
cacheID string
size int64
layerStore *layerStore
descriptor distribution.Descriptor
referenceCount int
references map[Layer]struct{}
}
// TarStream for roLayer guarantees that the data that is produced is the exact
// data that the layer was registered with.
func (rl *roLayer) TarStream() (io.ReadCloser, error) {
rc, err := rl.layerStore.getTarStream(rl)
if err != nil {
return nil, err
}
vrc, err := newVerifiedReadCloser(rc, digest.Digest(rl.diffID))
if err != nil {
return nil, err
}
return vrc, nil
}
// TarStreamFrom does not make any guarantees to the correctness of the produced
// data. As such it should not be used when the layer content must be verified
// to be an exact match to the registered layer.
func (rl *roLayer) TarStreamFrom(parent ChainID) (io.ReadCloser, error) {
var parentCacheID string
for pl := rl.parent; pl != nil; pl = pl.parent {
if pl.chainID == parent {
parentCacheID = pl.cacheID
break
}
}
if parent != ChainID("") && parentCacheID == "" {
return nil, fmt.Errorf("layer ID '%s' is not a parent of the specified layer: cannot provide diff to non-parent", parent)
}
return rl.layerStore.driver.Diff(rl.cacheID, parentCacheID)
}
func (rl *roLayer) CacheID() string {
return rl.cacheID
}
func (rl *roLayer) ChainID() ChainID {
return rl.chainID
}
func (rl *roLayer) DiffID() DiffID {
return rl.diffID
}
func (rl *roLayer) Parent() Layer {
if rl.parent == nil {
return nil
}
return rl.parent
}
func (rl *roLayer) Size() int64 {
size := rl.size
if rl.parent != nil {
size += rl.parent.Size()
}
return size
}
func (rl *roLayer) DiffSize() int64 {
return rl.size
}
func (rl *roLayer) Metadata() (map[string]string, error) {
return rl.layerStore.driver.GetMetadata(rl.cacheID)
}
type referencedCacheLayer struct {
*roLayer
}
func (rl *roLayer) getReference() Layer {
ref := &referencedCacheLayer{
roLayer: rl,
}
rl.references[ref] = struct{}{}
return ref
}
func (rl *roLayer) hasReference(ref Layer) bool {
_, ok := rl.references[ref]
return ok
}
func (rl *roLayer) hasReferences() bool {
return len(rl.references) > 0
}
func (rl *roLayer) deleteReference(ref Layer) {
delete(rl.references, ref)
}
func (rl *roLayer) depth() int {
if rl.parent == nil {
return 1
}
return rl.parent.depth() + 1
}
func storeLayer(tx *fileMetadataTransaction, layer *roLayer) error {
if err := tx.SetDiffID(layer.diffID); err != nil {
return err
}
if err := tx.SetSize(layer.size); err != nil {
return err
}
if err := tx.SetCacheID(layer.cacheID); err != nil {
return err
}
// Do not store empty descriptors
if layer.descriptor.Digest != "" {
if err := tx.SetDescriptor(layer.descriptor); err != nil {
return err
}
}
if layer.parent != nil {
if err := tx.SetParent(layer.parent.chainID); err != nil {
return err
}
}
return nil
}
func newVerifiedReadCloser(rc io.ReadCloser, dgst digest.Digest) (io.ReadCloser, error) {
return &verifiedReadCloser{
rc: rc,
dgst: dgst,
verifier: dgst.Verifier(),
}, nil
}
type verifiedReadCloser struct {
rc io.ReadCloser
dgst digest.Digest
verifier digest.Verifier
}
func (vrc *verifiedReadCloser) Read(p []byte) (n int, err error) {
n, err = vrc.rc.Read(p)
if n > 0 {
if n, err := vrc.verifier.Write(p[:n]); err != nil {
return n, err
}
}
if err == io.EOF {
if !vrc.verifier.Verified() {
err = fmt.Errorf("could not verify layer data for: %s. This may be because internal files in the layer store were modified. Re-pulling or rebuilding this image may resolve the issue", vrc.dgst)
}
}
return
}
func (vrc *verifiedReadCloser) Close() error {
return vrc.rc.Close()
}
|
