-
Notifications
You must be signed in to change notification settings - Fork 15
/
rewriteLayer.go
116 lines (98 loc) · 2.97 KB
/
rewriteLayer.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
package buildpack
import (
"archive/tar"
"bytes"
"fmt"
"io"
"path"
"strings"
"github.com/BurntSushi/toml"
v1 "github.com/google/go-containerregistry/pkg/v1"
"github.com/google/go-containerregistry/pkg/v1/tarball"
)
func rewriteLayer(layer v1.Layer, oldID, newID, oldVersion, newVersion string) (v1.Layer, error) {
b := &bytes.Buffer{}
tw := tar.NewWriter(b)
uncompressed, err := layer.Uncompressed()
if err != nil {
return nil, fmt.Errorf("unable to get uncompressed layer contents\n%w", err)
}
defer uncompressed.Close()
tr := tar.NewReader(uncompressed)
for {
header, err := tr.Next()
if err != nil {
break
}
// replace buildpack id and version in folder names
newName := strings.ReplaceAll(
strings.ReplaceAll(header.Name, escapedID(oldID), escapedID(newID)),
oldVersion, newVersion)
// replace buildpack id and version in buildpack.toml
if strings.HasSuffix(path.Clean(header.Name), "buildpack.toml") {
buf, err := io.ReadAll(tr)
if err != nil {
return nil, fmt.Errorf("unable to read buildpack.toml\n%w", err)
}
bd := BuildpackDescriptor{}
_, err = toml.Decode(string(buf), &bd)
if err != nil {
return nil, fmt.Errorf("unable to decode buildpack.toml\n%w", err)
}
bd.Info.ID = newID
bd.Info.Version = newVersion
updatedBuildpackToml := &bytes.Buffer{}
err = toml.NewEncoder(updatedBuildpackToml).Encode(bd)
if err != nil {
return nil, fmt.Errorf("unable to encode buildpack.toml\n%w", err)
}
contents := updatedBuildpackToml.Bytes()
header.Name = newName
header.Size = int64(len(contents))
err = tw.WriteHeader(header)
if err != nil {
return nil, fmt.Errorf("unable to write updated header\n%w", err)
}
_, err = tw.Write(contents)
if err != nil {
return nil, fmt.Errorf("unable to write updated contents\n%w", err)
}
} else {
header.Name = newName
err = tw.WriteHeader(header)
if err != nil {
return nil, fmt.Errorf("unable to write header\n%w", err)
}
buf, err := io.ReadAll(tr)
if err != nil {
return nil, fmt.Errorf("unable to read contents\n%w", err)
}
_, err = tw.Write(buf)
if err != nil {
return nil, fmt.Errorf("unable to write contents\n%w", err)
}
}
}
return tarball.LayerFromOpener(func() (io.ReadCloser, error) {
return io.NopCloser(b), nil
})
}
type BuildpackDescriptor struct {
API string `toml:"api"`
Info BuildpackTomlInfo `toml:"buildpack"`
Stacks interface{} `toml:"stacks"`
Order interface{} `toml:"order"`
Metadata interface{} `toml:"metadata"`
}
type BuildpackTomlInfo struct {
ID string `toml:"id"`
Version string `toml:"version"`
Name string `toml:"name"`
ClearEnv bool `toml:"clear-env,omitempty"`
SBOMFormats []string `toml:"sbom-formats,omitempty"`
Description string `toml:"description,omitempty"`
Homepage string `toml:"homepage,omitempty"`
}
func escapedID(id string) string {
return strings.ReplaceAll(id, "/", "_")
}