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
|
// Copyright 2023 Google LLC All Rights Reserved.
//
// 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 remote
import (
"bytes"
"context"
"errors"
"io"
"net/http"
"strings"
"github.com/google/go-containerregistry/pkg/name"
v1 "github.com/google/go-containerregistry/pkg/v1"
"github.com/google/go-containerregistry/pkg/v1/empty"
"github.com/google/go-containerregistry/pkg/v1/mutate"
"github.com/google/go-containerregistry/pkg/v1/remote/transport"
"github.com/google/go-containerregistry/pkg/v1/types"
)
// Referrers returns a list of descriptors that refer to the given manifest digest.
//
// The subject manifest doesn't have to exist in the registry for there to be descriptors that refer to it.
func Referrers(d name.Digest, options ...Option) (v1.ImageIndex, error) {
o, err := makeOptions(options...)
if err != nil {
return nil, err
}
return newPuller(o).referrers(o.context, d, o.filter)
}
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#referrers-tag-schema
func fallbackTag(d name.Digest) name.Tag {
return d.Context().Tag(strings.Replace(d.DigestStr(), ":", "-", 1))
}
func (f *fetcher) fetchReferrers(ctx context.Context, filter map[string]string, d name.Digest) (v1.ImageIndex, error) {
// Check the Referrers API endpoint first.
u := f.url("referrers", d.DigestStr())
req, err := http.NewRequestWithContext(ctx, http.MethodGet, u.String(), nil)
if err != nil {
return nil, err
}
req.Header.Set("Accept", string(types.OCIImageIndex))
resp, err := f.client.Do(req)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if err := transport.CheckError(resp, http.StatusOK, http.StatusNotFound, http.StatusBadRequest); err != nil {
return nil, err
}
var b []byte
if resp.StatusCode == http.StatusOK {
b, err = io.ReadAll(resp.Body)
if err != nil {
return nil, err
}
} else {
// The registry doesn't support the Referrers API endpoint, so we'll use the fallback tag scheme.
b, _, err = f.fetchManifest(ctx, fallbackTag(d), []types.MediaType{types.OCIImageIndex})
var terr *transport.Error
if errors.As(err, &terr) && terr.StatusCode == http.StatusNotFound {
// Not found just means there are no attachments yet. Start with an empty manifest.
return empty.Index, nil
} else if err != nil {
return nil, err
}
}
h, sz, err := v1.SHA256(bytes.NewReader(b))
if err != nil {
return nil, err
}
idx := &remoteIndex{
fetcher: *f,
ctx: ctx,
manifest: b,
mediaType: types.OCIImageIndex,
descriptor: &v1.Descriptor{
Digest: h,
MediaType: types.OCIImageIndex,
Size: sz,
},
}
return filterReferrersResponse(filter, idx), nil
}
// If filter applied, filter out by artifactType.
// See https://github.com/opencontainers/distribution-spec/blob/main/spec.md#listing-referrers
func filterReferrersResponse(filter map[string]string, in v1.ImageIndex) v1.ImageIndex {
if filter == nil {
return in
}
v, ok := filter["artifactType"]
if !ok {
return in
}
return mutate.RemoveManifests(in, func(desc v1.Descriptor) bool {
return desc.ArtifactType != v
})
}
|
