Move garbage collect code into storage package

Signed-off-by: Richard Scothern <richard.scothern@docker.com>

docs/storage/garbagecollect.go

@@ -0,0 +1,150 @@
+package storage
+
+import (
+	"fmt"
+
+	"github.com/docker/distribution"
+	"github.com/docker/distribution/context"
+	"github.com/docker/distribution/digest"
+	"github.com/docker/distribution/manifest/schema1"
+	"github.com/docker/distribution/manifest/schema2"
+	"github.com/docker/distribution/reference"
+	"github.com/docker/distribution/registry/storage/driver"
+)
+
+func emit(format string, a ...interface{}) {
+	fmt.Printf(format+"\n", a...)
+}
+
+// MarkAndSweep performs a mark and sweep of registry data
+func MarkAndSweep(ctx context.Context, storageDriver driver.StorageDriver, registry distribution.Namespace, dryRun bool) error {
+	repositoryEnumerator, ok := registry.(distribution.RepositoryEnumerator)
+	if !ok {
+		return fmt.Errorf("unable to convert Namespace to RepositoryEnumerator")
+	}
+
+	// mark
+	markSet := make(map[digest.Digest]struct{})
+	err := repositoryEnumerator.Enumerate(ctx, func(repoName string) error {
+		if dryRun {
+			emit(repoName)
+		}
+
+		var err error
+		named, err := reference.ParseNamed(repoName)
+		if err != nil {
+			return fmt.Errorf("failed to parse repo name %s: %v", repoName, err)
+		}
+		repository, err := registry.Repository(ctx, named)
+		if err != nil {
+			return fmt.Errorf("failed to construct repository: %v", err)
+		}
+
+		manifestService, err := repository.Manifests(ctx)
+		if err != nil {
+			return fmt.Errorf("failed to construct manifest service: %v", err)
+		}
+
+		manifestEnumerator, ok := manifestService.(distribution.ManifestEnumerator)
+		if !ok {
+			return fmt.Errorf("unable to convert ManifestService into ManifestEnumerator")
+		}
+
+		err = manifestEnumerator.Enumerate(ctx, func(dgst digest.Digest) error {
+			// Mark the manifest's blob
+			if dryRun {
+				emit("%s: marking manifest %s ", repoName, dgst)
+			}
+			markSet[dgst] = struct{}{}
+
+			manifest, err := manifestService.Get(ctx, dgst)
+			if err != nil {
+				return fmt.Errorf("failed to retrieve manifest for digest %v: %v", dgst, err)
+			}
+
+			descriptors := manifest.References()
+			for _, descriptor := range descriptors {
+				markSet[descriptor.Digest] = struct{}{}
+				if dryRun {
+					emit("%s: marking blob %s", repoName, descriptor.Digest)
+				}
+			}
+
+			switch manifest.(type) {
+			case *schema1.SignedManifest:
+				signaturesGetter, ok := manifestService.(distribution.SignaturesGetter)
+				if !ok {
+					return fmt.Errorf("unable to convert ManifestService into SignaturesGetter")
+				}
+				signatures, err := signaturesGetter.GetSignatures(ctx, dgst)
+				if err != nil {
+					return fmt.Errorf("failed to get signatures for signed manifest: %v", err)
+				}
+				for _, signatureDigest := range signatures {
+					if dryRun {
+						emit("%s: marking signature %s", repoName, signatureDigest)
+					}
+					markSet[signatureDigest] = struct{}{}
+				}
+				break
+			case *schema2.DeserializedManifest:
+				config := manifest.(*schema2.DeserializedManifest).Config
+				if dryRun {
+					emit("%s: marking configuration %s", repoName, config.Digest)
+				}
+				markSet[config.Digest] = struct{}{}
+				break
+			}
+
+			return nil
+		})
+
+		if err != nil {
+			// In certain situations such as unfinished uploads, deleting all
+			// tags in S3 or removing the _manifests folder manually, this
+			// error may be of type PathNotFound.
+			//
+			// In these cases we can continue marking other manifests safely.
+			if _, ok := err.(driver.PathNotFoundError); ok {
+				return nil
+			}
+		}
+
+		return err
+	})
+
+	if err != nil {
+		return fmt.Errorf("failed to mark: %v\n", err)
+	}
+
+	// sweep
+	blobService := registry.Blobs()
+	deleteSet := make(map[digest.Digest]struct{})
+	err = blobService.Enumerate(ctx, func(dgst digest.Digest) error {
+		// check if digest is in markSet. If not, delete it!
+		if _, ok := markSet[dgst]; !ok {
+			deleteSet[dgst] = struct{}{}
+		}
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("error enumerating blobs: %v", err)
+	}
+	if dryRun {
+		emit("\n%d blobs marked, %d blobs eligible for deletion", len(markSet), len(deleteSet))
+	}
+	// Construct vacuum
+	vacuum := NewVacuum(ctx, storageDriver)
+	for dgst := range deleteSet {
+		if dryRun {
+			emit("blob eligible for deletion: %s", dgst)
+			continue
+		}
+		err = vacuum.RemoveBlob(string(dgst))
+		if err != nil {
+			return fmt.Errorf("failed to delete blob %s: %v\n", dgst, err)
+		}
+	}
+
+	return err
+}