269 lines
		
	
	
		
			8.4 KiB
		
	
	
	
		
			Go
		
	
	
			
		
		
	
	
			269 lines
		
	
	
		
			8.4 KiB
		
	
	
	
		
			Go
		
	
	
package redis
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import (
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	"context"
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	"fmt"
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	"github.com/docker/distribution"
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	"github.com/docker/distribution/reference"
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	"github.com/docker/distribution/registry/storage/cache"
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	"github.com/garyburd/redigo/redis"
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	"github.com/opencontainers/go-digest"
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)
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// redisBlobStatService provides an implementation of
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// BlobDescriptorCacheProvider based on redis. Blob descriptors are stored in
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// two parts. The first provide fast access to repository membership through a
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// redis set for each repo. The second is a redis hash keyed by the digest of
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// the layer, providing path, length and mediatype information. There is also
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// a per-repository redis hash of the blob descriptor, allowing override of
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// data. This is currently used to override the mediatype on a per-repository
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// basis.
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//
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// Note that there is no implied relationship between these two caches. The
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// layer may exist in one, both or none and the code must be written this way.
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type redisBlobDescriptorService struct {
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	pool *redis.Pool
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	// TODO(stevvooe): We use a pool because we don't have great control over
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	// the cache lifecycle to manage connections. A new connection if fetched
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	// for each operation. Once we have better lifecycle management of the
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	// request objects, we can change this to a connection.
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}
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// NewRedisBlobDescriptorCacheProvider returns a new redis-based
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// BlobDescriptorCacheProvider using the provided redis connection pool.
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func NewRedisBlobDescriptorCacheProvider(pool *redis.Pool) cache.BlobDescriptorCacheProvider {
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	return &redisBlobDescriptorService{
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		pool: pool,
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	}
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}
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// RepositoryScoped returns the scoped cache.
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func (rbds *redisBlobDescriptorService) RepositoryScoped(repo string) (distribution.BlobDescriptorService, error) {
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	if _, err := reference.ParseNormalizedNamed(repo); err != nil {
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		return nil, err
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	}
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	return &repositoryScopedRedisBlobDescriptorService{
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		repo:     repo,
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		upstream: rbds,
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	}, nil
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}
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// Stat retrieves the descriptor data from the redis hash entry.
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func (rbds *redisBlobDescriptorService) Stat(ctx context.Context, dgst digest.Digest) (distribution.Descriptor, error) {
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	if err := dgst.Validate(); err != nil {
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		return distribution.Descriptor{}, err
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	}
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	conn := rbds.pool.Get()
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	defer conn.Close()
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	return rbds.stat(ctx, conn, dgst)
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}
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func (rbds *redisBlobDescriptorService) Clear(ctx context.Context, dgst digest.Digest) error {
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	if err := dgst.Validate(); err != nil {
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		return err
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	}
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	conn := rbds.pool.Get()
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	defer conn.Close()
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	// Not atomic in redis <= 2.3
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	reply, err := conn.Do("HDEL", rbds.blobDescriptorHashKey(dgst), "digest", "size", "mediatype")
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	if err != nil {
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		return err
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	}
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	if reply == 0 {
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		return distribution.ErrBlobUnknown
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	}
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	return nil
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}
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// stat provides an internal stat call that takes a connection parameter. This
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// allows some internal management of the connection scope.
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func (rbds *redisBlobDescriptorService) stat(ctx context.Context, conn redis.Conn, dgst digest.Digest) (distribution.Descriptor, error) {
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	reply, err := redis.Values(conn.Do("HMGET", rbds.blobDescriptorHashKey(dgst), "digest", "size", "mediatype"))
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	if err != nil {
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		return distribution.Descriptor{}, err
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	}
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	// NOTE(stevvooe): The "size" field used to be "length". We treat a
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	// missing "size" field here as an unknown blob, which causes a cache
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	// miss, effectively migrating the field.
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	if len(reply) < 3 || reply[0] == nil || reply[1] == nil { // don't care if mediatype is nil
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		return distribution.Descriptor{}, distribution.ErrBlobUnknown
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	}
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	var desc distribution.Descriptor
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	if _, err := redis.Scan(reply, &desc.Digest, &desc.Size, &desc.MediaType); err != nil {
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		return distribution.Descriptor{}, err
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	}
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	return desc, nil
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}
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// SetDescriptor sets the descriptor data for the given digest using a redis
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// hash. A hash is used here since we may store unrelated fields about a layer
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// in the future.
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func (rbds *redisBlobDescriptorService) SetDescriptor(ctx context.Context, dgst digest.Digest, desc distribution.Descriptor) error {
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	if err := dgst.Validate(); err != nil {
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		return err
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	}
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	if err := cache.ValidateDescriptor(desc); err != nil {
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		return err
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	}
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	conn := rbds.pool.Get()
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	defer conn.Close()
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	return rbds.setDescriptor(ctx, conn, dgst, desc)
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}
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func (rbds *redisBlobDescriptorService) setDescriptor(ctx context.Context, conn redis.Conn, dgst digest.Digest, desc distribution.Descriptor) error {
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	if _, err := conn.Do("HMSET", rbds.blobDescriptorHashKey(dgst),
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		"digest", desc.Digest,
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		"size", desc.Size); err != nil {
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		return err
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	}
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	// Only set mediatype if not already set.
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	if _, err := conn.Do("HSETNX", rbds.blobDescriptorHashKey(dgst),
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		"mediatype", desc.MediaType); err != nil {
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		return err
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	}
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	return nil
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}
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func (rbds *redisBlobDescriptorService) blobDescriptorHashKey(dgst digest.Digest) string {
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	return "blobs::" + dgst.String()
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}
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type repositoryScopedRedisBlobDescriptorService struct {
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	repo     string
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	upstream *redisBlobDescriptorService
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}
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var _ distribution.BlobDescriptorService = &repositoryScopedRedisBlobDescriptorService{}
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// Stat ensures that the digest is a member of the specified repository and
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// forwards the descriptor request to the global blob store. If the media type
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// differs for the repository, we override it.
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func (rsrbds *repositoryScopedRedisBlobDescriptorService) Stat(ctx context.Context, dgst digest.Digest) (distribution.Descriptor, error) {
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	if err := dgst.Validate(); err != nil {
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		return distribution.Descriptor{}, err
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	}
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	conn := rsrbds.upstream.pool.Get()
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	defer conn.Close()
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	// Check membership to repository first
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	member, err := redis.Bool(conn.Do("SISMEMBER", rsrbds.repositoryBlobSetKey(rsrbds.repo), dgst))
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	if err != nil {
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		return distribution.Descriptor{}, err
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	}
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	if !member {
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		return distribution.Descriptor{}, distribution.ErrBlobUnknown
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	}
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	upstream, err := rsrbds.upstream.stat(ctx, conn, dgst)
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	if err != nil {
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		return distribution.Descriptor{}, err
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	}
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	// We allow a per repository mediatype, let's look it up here.
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	mediatype, err := redis.String(conn.Do("HGET", rsrbds.blobDescriptorHashKey(dgst), "mediatype"))
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	if err != nil {
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		return distribution.Descriptor{}, err
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	}
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	if mediatype != "" {
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		upstream.MediaType = mediatype
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	}
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	return upstream, nil
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}
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// Clear removes the descriptor from the cache and forwards to the upstream descriptor store
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func (rsrbds *repositoryScopedRedisBlobDescriptorService) Clear(ctx context.Context, dgst digest.Digest) error {
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	if err := dgst.Validate(); err != nil {
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		return err
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	}
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	conn := rsrbds.upstream.pool.Get()
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	defer conn.Close()
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	// Check membership to repository first
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	member, err := redis.Bool(conn.Do("SISMEMBER", rsrbds.repositoryBlobSetKey(rsrbds.repo), dgst))
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	if err != nil {
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		return err
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	}
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	if !member {
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		return distribution.ErrBlobUnknown
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	}
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	return rsrbds.upstream.Clear(ctx, dgst)
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}
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func (rsrbds *repositoryScopedRedisBlobDescriptorService) SetDescriptor(ctx context.Context, dgst digest.Digest, desc distribution.Descriptor) error {
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	if err := dgst.Validate(); err != nil {
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		return err
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	}
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	if err := cache.ValidateDescriptor(desc); err != nil {
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		return err
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	}
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	if dgst != desc.Digest {
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		if dgst.Algorithm() == desc.Digest.Algorithm() {
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			return fmt.Errorf("redis cache: digest for descriptors differ but algorithm does not: %q != %q", dgst, desc.Digest)
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		}
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	}
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	conn := rsrbds.upstream.pool.Get()
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	defer conn.Close()
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	return rsrbds.setDescriptor(ctx, conn, dgst, desc)
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}
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func (rsrbds *repositoryScopedRedisBlobDescriptorService) setDescriptor(ctx context.Context, conn redis.Conn, dgst digest.Digest, desc distribution.Descriptor) error {
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	if _, err := conn.Do("SADD", rsrbds.repositoryBlobSetKey(rsrbds.repo), dgst); err != nil {
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		return err
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	}
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	if err := rsrbds.upstream.setDescriptor(ctx, conn, dgst, desc); err != nil {
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		return err
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	}
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	// Override repository mediatype.
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	if _, err := conn.Do("HSET", rsrbds.blobDescriptorHashKey(dgst), "mediatype", desc.MediaType); err != nil {
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		return err
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	}
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	// Also set the values for the primary descriptor, if they differ by
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	// algorithm (ie sha256 vs sha512).
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	if desc.Digest != "" && dgst != desc.Digest && dgst.Algorithm() != desc.Digest.Algorithm() {
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		if err := rsrbds.setDescriptor(ctx, conn, desc.Digest, desc); err != nil {
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			return err
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		}
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	}
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	return nil
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}
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func (rsrbds *repositoryScopedRedisBlobDescriptorService) blobDescriptorHashKey(dgst digest.Digest) string {
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	return "repository::" + rsrbds.repo + "::blobs::" + dgst.String()
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}
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func (rsrbds *repositoryScopedRedisBlobDescriptorService) repositoryBlobSetKey(repo string) string {
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	return "repository::" + rsrbds.repo + "::blobs"
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}
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