-
Notifications
You must be signed in to change notification settings - Fork 18.6k
/
fsdiff.go
175 lines (147 loc) · 4.79 KB
/
fsdiff.go
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
package graphdriver // import "github.com/docker/docker/daemon/graphdriver"
import (
"io"
"time"
"github.com/docker/docker/pkg/archive"
"github.com/docker/docker/pkg/chrootarchive"
"github.com/docker/docker/pkg/idtools"
"github.com/docker/docker/pkg/ioutils"
"github.com/sirupsen/logrus"
)
var (
// ApplyUncompressedLayer defines the unpack method used by the graph
// driver.
ApplyUncompressedLayer = chrootarchive.ApplyUncompressedLayer
)
// NaiveDiffDriver takes a ProtoDriver and adds the
// capability of the Diffing methods on the local file system,
// which it may or may not support on its own. See the comment
// on the exported NewNaiveDiffDriver function below.
// Notably, the AUFS driver doesn't need to be wrapped like this.
type NaiveDiffDriver struct {
ProtoDriver
uidMaps []idtools.IDMap
gidMaps []idtools.IDMap
}
// NewNaiveDiffDriver returns a fully functional driver that wraps the
// given ProtoDriver and adds the capability of the following methods which
// it may or may not support on its own:
// Diff(id, parent string) (archive.Archive, error)
// Changes(id, parent string) ([]archive.Change, error)
// ApplyDiff(id, parent string, diff archive.Reader) (size int64, err error)
// DiffSize(id, parent string) (size int64, err error)
func NewNaiveDiffDriver(driver ProtoDriver, uidMaps, gidMaps []idtools.IDMap) Driver {
return &NaiveDiffDriver{ProtoDriver: driver,
uidMaps: uidMaps,
gidMaps: gidMaps}
}
// Diff produces an archive of the changes between the specified
// layer and its parent layer which may be "".
func (gdw *NaiveDiffDriver) Diff(id, parent string) (arch io.ReadCloser, err error) {
startTime := time.Now()
driver := gdw.ProtoDriver
layerRootFs, err := driver.Get(id, "")
if err != nil {
return nil, err
}
layerFs := layerRootFs.Path()
defer func() {
if err != nil {
driver.Put(id)
}
}()
if parent == "" {
archive, err := archive.Tar(layerFs, archive.Uncompressed)
if err != nil {
return nil, err
}
return ioutils.NewReadCloserWrapper(archive, func() error {
err := archive.Close()
driver.Put(id)
return err
}), nil
}
parentRootFs, err := driver.Get(parent, "")
if err != nil {
return nil, err
}
defer driver.Put(parent)
parentFs := parentRootFs.Path()
changes, err := archive.ChangesDirs(layerFs, parentFs)
if err != nil {
return nil, err
}
archive, err := archive.ExportChanges(layerFs, changes, gdw.uidMaps, gdw.gidMaps)
if err != nil {
return nil, err
}
return ioutils.NewReadCloserWrapper(archive, func() error {
err := archive.Close()
driver.Put(id)
// NaiveDiffDriver compares file metadata with parent layers. Parent layers
// are extracted from tar's with full second precision on modified time.
// We need this hack here to make sure calls within same second receive
// correct result.
time.Sleep(time.Until(startTime.Truncate(time.Second).Add(time.Second)))
return err
}), nil
}
// Changes produces a list of changes between the specified layer
// and its parent layer. If parent is "", then all changes will be ADD changes.
func (gdw *NaiveDiffDriver) Changes(id, parent string) ([]archive.Change, error) {
driver := gdw.ProtoDriver
layerRootFs, err := driver.Get(id, "")
if err != nil {
return nil, err
}
defer driver.Put(id)
layerFs := layerRootFs.Path()
parentFs := ""
if parent != "" {
parentRootFs, err := driver.Get(parent, "")
if err != nil {
return nil, err
}
defer driver.Put(parent)
parentFs = parentRootFs.Path()
}
return archive.ChangesDirs(layerFs, parentFs)
}
// ApplyDiff extracts the changeset from the given diff into the
// layer with the specified id and parent, returning the size of the
// new layer in bytes.
func (gdw *NaiveDiffDriver) ApplyDiff(id, parent string, diff io.Reader) (size int64, err error) {
driver := gdw.ProtoDriver
// Mount the root filesystem so we can apply the diff/layer.
layerRootFs, err := driver.Get(id, "")
if err != nil {
return
}
defer driver.Put(id)
layerFs := layerRootFs.Path()
options := &archive.TarOptions{UIDMaps: gdw.uidMaps,
GIDMaps: gdw.gidMaps}
start := time.Now().UTC()
logrus.WithField("id", id).Debug("Start untar layer")
if size, err = ApplyUncompressedLayer(layerFs, diff, options); err != nil {
return
}
logrus.WithField("id", id).Debugf("Untar time: %vs", time.Now().UTC().Sub(start).Seconds())
return
}
// DiffSize calculates the changes between the specified layer
// and its parent and returns the size in bytes of the changes
// relative to its base filesystem directory.
func (gdw *NaiveDiffDriver) DiffSize(id, parent string) (size int64, err error) {
driver := gdw.ProtoDriver
changes, err := gdw.Changes(id, parent)
if err != nil {
return
}
layerFs, err := driver.Get(id, "")
if err != nil {
return
}
defer driver.Put(id)
return archive.ChangesSize(layerFs.Path(), changes), nil
}