forked from TrueCloudLab/distribution
a7c2dceea5
This changeset defines the interface for layer info caches. Layer info caches speed up access to layer meta data accessed in storage driver backends. The two main operations are tests for repository membership and resolving path and size information for backend blobs. Two implementations are available. The main implementation leverages redis to store layer info. An alternative implementation simply caches layer info in maps, which should speed up resolution for less sophisticated implementations. Signed-off-by: Stephen J Day <stephen.day@docker.com>
63 lines
1.7 KiB
Go
63 lines
1.7 KiB
Go
package cache
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import (
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"github.com/docker/distribution/digest"
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"golang.org/x/net/context"
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)
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// inmemoryLayerInfoCache is a map-based implementation of LayerInfoCache.
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type inmemoryLayerInfoCache struct {
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membership map[string]map[digest.Digest]struct{}
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meta map[digest.Digest]LayerMeta
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}
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// NewInMemoryLayerInfoCache provides an implementation of LayerInfoCache that
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// stores results in memory.
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func NewInMemoryLayerInfoCache() LayerInfoCache {
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return &base{&inmemoryLayerInfoCache{
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membership: make(map[string]map[digest.Digest]struct{}),
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meta: make(map[digest.Digest]LayerMeta),
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}}
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}
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func (ilic *inmemoryLayerInfoCache) Contains(ctx context.Context, repo string, dgst digest.Digest) (bool, error) {
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members, ok := ilic.membership[repo]
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if !ok {
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return false, nil
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}
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_, ok = members[dgst]
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return ok, nil
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}
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// Add adds the layer to the redis repository blob set.
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func (ilic *inmemoryLayerInfoCache) Add(ctx context.Context, repo string, dgst digest.Digest) error {
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members, ok := ilic.membership[repo]
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if !ok {
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members = make(map[digest.Digest]struct{})
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ilic.membership[repo] = members
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}
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members[dgst] = struct{}{}
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return nil
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}
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// Meta retrieves the layer meta data from the redis hash, returning
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// ErrUnknownLayer if not found.
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func (ilic *inmemoryLayerInfoCache) Meta(ctx context.Context, dgst digest.Digest) (LayerMeta, error) {
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meta, ok := ilic.meta[dgst]
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if !ok {
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return LayerMeta{}, ErrNotFound
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}
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return meta, nil
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}
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// SetMeta sets the meta data for the given digest using a redis hash. A hash
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// is used here since we may store unrelated fields about a layer in the
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// future.
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func (ilic *inmemoryLayerInfoCache) SetMeta(ctx context.Context, dgst digest.Digest, meta LayerMeta) error {
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ilic.meta[dgst] = meta
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return nil
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}
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