97 lines
3.8 KiB
Go
97 lines
3.8 KiB
Go
/*
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Copyright The containerd Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package snapshotters
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import (
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"context"
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"github.com/containerd/containerd/v2/core/images"
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"github.com/containerd/containerd/v2/pkg/labels"
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"github.com/containerd/log"
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ocispec "github.com/opencontainers/image-spec/specs-go/v1"
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)
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// NOTE: The following labels contain "cri" prefix but they are not specific to CRI and
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// can be used by non-CRI clients as well for enabling remote snapshotters. We need to
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// retain that string for keeping compatibility with snapshotter implementations.
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const (
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// TargetRefLabel is a label which contains image reference and will be passed
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// to snapshotters.
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TargetRefLabel = "containerd.io/snapshot/cri.image-ref"
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// TargetManifestDigestLabel is a label which contains manifest digest and will be passed
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// to snapshotters.
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TargetManifestDigestLabel = "containerd.io/snapshot/cri.manifest-digest"
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// TargetLayerDigestLabel is a label which contains layer digest and will be passed
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// to snapshotters.
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TargetLayerDigestLabel = "containerd.io/snapshot/cri.layer-digest"
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// TargetImageLayersLabel is a label which contains layer digests contained in
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// the target image and will be passed to snapshotters for preparing layers in
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// parallel. Skipping some layers is allowed and only affects performance.
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TargetImageLayersLabel = "containerd.io/snapshot/cri.image-layers"
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)
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// AppendInfoHandlerWrapper makes a handler which appends some basic information
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// of images like digests for manifest and their child layers as annotations during unpack.
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// These annotations will be passed to snapshotters as labels. These labels will be
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// used mainly by remote snapshotters for querying image contents from the remote location.
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func AppendInfoHandlerWrapper(ref string) func(f images.Handler) images.Handler {
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return func(f images.Handler) images.Handler {
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return images.HandlerFunc(func(ctx context.Context, desc ocispec.Descriptor) ([]ocispec.Descriptor, error) {
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children, err := f.Handle(ctx, desc)
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if err != nil {
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return nil, err
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}
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if images.IsManifestType(desc.MediaType) {
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for i := range children {
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c := &children[i]
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if images.IsLayerType(c.MediaType) {
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if c.Annotations == nil {
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c.Annotations = make(map[string]string)
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}
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c.Annotations[TargetRefLabel] = ref
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c.Annotations[TargetLayerDigestLabel] = c.Digest.String()
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c.Annotations[TargetImageLayersLabel] = getLayers(ctx, TargetImageLayersLabel, children[i:], labels.Validate)
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c.Annotations[TargetManifestDigestLabel] = desc.Digest.String()
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}
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}
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}
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return children, nil
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})
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}
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}
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// getLayers returns comma-separated digests based on the passed list of
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// descriptors. The returned list contains as many digests as possible as well
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// as meets the label validation.
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func getLayers(ctx context.Context, key string, descs []ocispec.Descriptor, validate func(k, v string) error) (layers string) {
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for _, l := range descs {
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if images.IsLayerType(l.MediaType) {
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item := l.Digest.String()
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if layers != "" {
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item = "," + item
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}
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// This avoids the label hits the size limitation.
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if err := validate(key, layers+item); err != nil {
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log.G(ctx).WithError(err).WithField("label", key).WithField("digest", l.Digest.String()).Debug("omitting digest in the layers list")
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break
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}
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layers += item
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}
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}
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return
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}
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