zot/pkg/storage/cache/boltdb.go

package cache

import (
	"fmt"
	"os"
	"path"
	"path/filepath"
	"strings"

	godigest "github.com/opencontainers/go-digest"
	"go.etcd.io/bbolt"

	zerr "zotregistry.dev/zot/v2/errors"
	zlog "zotregistry.dev/zot/v2/pkg/log"
	"zotregistry.dev/zot/v2/pkg/storage/constants"
)

type BoltDBDriver struct {
	rootDir     string
	db          *bbolt.DB
	log         zlog.Logger
	useRelPaths bool // whether or not to use relative paths, should be true for filesystem and false for s3
}

type BoltDBDriverParameters struct {
	RootDir     string
	Name        string
	UseRelPaths bool
}

func NewBoltDBCache(parameters any, log zlog.Logger) (*BoltDBDriver, error) {
	properParameters, ok := parameters.(BoltDBDriverParameters)
	if !ok {
		log.Error().Err(zerr.ErrTypeAssertionFailed).Msgf("failed to cast type, expected type '%T' but got '%T'",
			BoltDBDriverParameters{}, parameters)

		return nil, zerr.ErrTypeAssertionFailed
	}

	err := os.MkdirAll(properParameters.RootDir, constants.DefaultDirPerms)
	if err != nil {
		log.Error().Err(err).Str("directory", properParameters.RootDir).Msg("failed to create directory for cache db")

		return nil, err
	}

	dbPath := path.Join(properParameters.RootDir, properParameters.Name+constants.DBExtensionName)
	dbOpts := &bbolt.Options{
		Timeout:      constants.DBCacheLockCheckTimeout,
		FreelistType: bbolt.FreelistArrayType,
	}

	cacheDB, err := bbolt.Open(dbPath, 0o600, dbOpts) //nolint:mnd
	if err != nil {
		if strings.Contains(err.Error(), "timeout") {
			err := fmt.Errorf("%w: %w, path '%s'", zerr.ErrTimeout, zerr.ErrDatabaseFileAlreadyInUse, dbPath)

			log.Error().Err(err).Str("dbPath", dbPath).Msg("failed to create cache db")

			return nil, err
		}

		log.Error().Err(err).Str("dbPath", dbPath).Msg("failed to create cache db")

		return nil, err
	}

	if err := cacheDB.Update(func(tx *bbolt.Tx) error {
		if _, err := tx.CreateBucketIfNotExists([]byte(constants.BlobsCache)); err != nil {
			// this is a serious failure
			log.Error().Err(err).Str("dbPath", dbPath).Msg("failed to create a root bucket")

			return err
		}

		return nil
	}); err != nil {
		// something went wrong
		log.Error().Err(err).Msg("failed to create a cache")

		return nil, err
	}

	return &BoltDBDriver{
		rootDir:     properParameters.RootDir,
		db:          cacheDB,
		useRelPaths: properParameters.UseRelPaths,
		log:         log,
	}, nil
}

func (d *BoltDBDriver) UsesRelativePaths() bool {
	return d.useRelPaths
}

func (d *BoltDBDriver) Name() string {
	return "boltdb"
}

func (d *BoltDBDriver) PutBlob(digest godigest.Digest, path string) error {
	if path == "" {
		d.log.Error().Err(zerr.ErrEmptyValue).Str("digest", digest.String()).
			Msg("failed to put blob due to empty path being provided")

		return zerr.ErrEmptyValue
	}

	// use only relative (to rootDir) paths on blobs
	var err error
	if d.useRelPaths {
		path, err = filepath.Rel(d.rootDir, path)
		if err != nil {
			d.log.Error().Err(err).Str("path", path).Msg("failed to get relative path")
		}
	}

	if len(path) == 0 {
		return zerr.ErrEmptyValue
	}

	if err := d.db.Update(func(tx *bbolt.Tx) error {
		root := tx.Bucket([]byte(constants.BlobsCache))
		if root == nil {
			// this is a serious failure
			err := zerr.ErrCacheRootBucket
			d.log.Error().Err(err).Msg("failed to access root bucket")

			return err
		}

		bucket, err := root.CreateBucketIfNotExists([]byte(digest.String()))
		if err != nil {
			// this is a serious failure
			d.log.Error().Err(err).Str("bucket", digest.String()).Msg("failed to create a bucket")

			return err
		}

		// create origin bucket and insert only the original blob
		origin := bucket.Bucket([]byte(constants.OriginalBucket))
		if origin == nil {
			// if the bucket doesn't exist yet then 'path' is the original blob
			origin, err := bucket.CreateBucket([]byte(constants.OriginalBucket))
			if err != nil {
				// this is a serious failure
				d.log.Error().Err(err).Str("bucket", constants.OriginalBucket).Msg("failed to create a bucket")

				return err
			}

			if err := origin.Put([]byte(path), nil); err != nil {
				d.log.Error().Err(err).Str("bucket", constants.OriginalBucket).Str("value", path).Msg("failed to put record")

				return err
			}

			return nil
		}

		// original bucket exists; if path is the same as the original, this is idempotent
		if origin.Get([]byte(path)) != nil {
			return nil
		}

		// otherwise, this is a duplicate blob - add to the duplicates bucket
		deduped, err := bucket.CreateBucketIfNotExists([]byte(constants.DuplicatesBucket))
		if err != nil {
			// this is a serious failure
			d.log.Error().Err(err).Str("bucket", constants.DuplicatesBucket).Msg("failed to create a bucket")

			return err
		}

		if err := deduped.Put([]byte(path), nil); err != nil {
			d.log.Error().Err(err).Str("bucket", constants.DuplicatesBucket).Str("value", path).Msg("failed to put record")

			return err
		}

		return nil
	}); err != nil {
		return err
	}

	return nil
}

func (d *BoltDBDriver) GetAllBlobs(digest godigest.Digest) ([]string, error) {
	var blobPath strings.Builder

	blobPaths := []string{}

	if err := d.db.View(func(tx *bbolt.Tx) error {
		root := tx.Bucket([]byte(constants.BlobsCache))
		if root == nil {
			// this is a serious failure
			err := zerr.ErrCacheRootBucket
			d.log.Error().Err(err).Msg("failed to access root bucket")

			return err
		}

		bucket := root.Bucket([]byte(digest.String()))
		if bucket != nil {
			origin := bucket.Bucket([]byte(constants.OriginalBucket))
			blobPath.Write(d.getOne(origin))
			originBlob := blobPath.String()

			blobPaths = append(blobPaths, originBlob)

			deduped := bucket.Bucket([]byte(constants.DuplicatesBucket))
			if deduped != nil {
				cursor := deduped.Cursor()

				for k, _ := cursor.First(); k != nil; k, _ = cursor.Next() {
					var blobPath strings.Builder

					blobPath.Write(k)

					duplicateBlob := blobPath.String()

					if duplicateBlob != originBlob {
						blobPaths = append(blobPaths, duplicateBlob)
					}
				}

				return nil
			}
		}

		return zerr.ErrCacheMiss
	}); err != nil {
		return nil, err
	}

	return blobPaths, nil
}

func (d *BoltDBDriver) GetBlob(digest godigest.Digest) (string, error) {
	var blobPath strings.Builder

	if err := d.db.View(func(tx *bbolt.Tx) error {
		root := tx.Bucket([]byte(constants.BlobsCache))
		if root == nil {
			// this is a serious failure
			err := zerr.ErrCacheRootBucket
			d.log.Error().Err(err).Msg("failed to access root bucket")

			return err
		}

		bucket := root.Bucket([]byte(digest.String()))
		if bucket != nil {
			origin := bucket.Bucket([]byte(constants.OriginalBucket))
			blobPath.Write(d.getOne(origin))

			return nil
		}

		return zerr.ErrCacheMiss
	}); err != nil {
		return "", err
	}

	return blobPath.String(), nil
}

func (d *BoltDBDriver) HasBlob(digest godigest.Digest, blob string) bool {
	if err := d.db.View(func(tx *bbolt.Tx) error {
		root := tx.Bucket([]byte(constants.BlobsCache))
		if root == nil {
			// this is a serious failure
			err := zerr.ErrCacheRootBucket
			d.log.Error().Err(err).Msg("failed to access root bucket")

			return err
		}

		bucket := root.Bucket([]byte(digest.String()))
		if bucket == nil {
			return zerr.ErrCacheMiss
		}

		origin := bucket.Bucket([]byte(constants.OriginalBucket))
		if origin == nil {
			return zerr.ErrCacheMiss
		}

		// check original bucket first
		if origin.Get([]byte(blob)) != nil {
			return nil
		}

		// check duplicates bucket
		deduped := bucket.Bucket([]byte(constants.DuplicatesBucket))
		if deduped != nil {
			if deduped.Get([]byte(blob)) != nil {
				return nil
			}
		}

		return zerr.ErrCacheMiss
	}); err != nil {
		return false
	}

	return true
}

func (d *BoltDBDriver) getOne(bucket *bbolt.Bucket) []byte {
	if bucket != nil {
		cursor := bucket.Cursor()
		k, _ := cursor.First()

		return k
	}

	return nil
}

func (d *BoltDBDriver) DeleteBlob(digest godigest.Digest, path string) error {
	// use only relative (to rootDir) paths on blobs
	var err error
	if d.useRelPaths {
		path, err = filepath.Rel(d.rootDir, path)
		if err != nil {
			d.log.Error().Err(err).Str("path", path).Msg("failed to get relative path")
		}
	}

	if err := d.db.Update(func(tx *bbolt.Tx) error {
		root := tx.Bucket([]byte(constants.BlobsCache))
		if root == nil {
			// this is a serious failure
			err := zerr.ErrCacheRootBucket
			d.log.Error().Err(err).Msg("failed to access root bucket")

			return err
		}

		bucket := root.Bucket([]byte(digest.String()))
		if bucket == nil {
			return zerr.ErrCacheMiss
		}

		// check duplicates bucket first
		deduped := bucket.Bucket([]byte(constants.DuplicatesBucket))
		if deduped != nil {
			if deduped.Get([]byte(path)) != nil {
				if err := deduped.Delete([]byte(path)); err != nil {
					d.log.Error().Err(err).Str("digest", digest.String()).Str("bucket", constants.DuplicatesBucket).
						Str("path", path).Msg("failed to delete")

					return err
				}

				return nil
			}
		}

		// check original bucket
		origin := bucket.Bucket([]byte(constants.OriginalBucket))
		deleted := false

		if origin != nil {
			if origin.Get([]byte(path)) != nil {
				// if duplicates still exist, keep the original (global blobstore file stays)
				if deduped != nil && d.getOne(deduped) != nil {
					return nil
				}

				// no more duplicates, safe to remove the original
				if err := origin.Delete([]byte(path)); err != nil {
					d.log.Error().Err(err).Str("digest", digest.String()).Str("bucket", constants.OriginalBucket).
						Str("path", path).Msg("failed to delete")

					return err
				}

				deleted = true
			}
		}

		if !deleted {
			return zerr.ErrCacheMiss
		}

		// if no key in origin bucket then digest bucket is empty, remove it
		k := d.getOne(origin)
		if k == nil {
			d.log.Debug().Str("digest", digest.String()).Str("path", path).Msg("deleting empty bucket")
			if err := root.DeleteBucket([]byte(digest)); err != nil {
				d.log.Error().Err(err).Str("digest", digest.String()).Str("bucket", digest.String()).Str("path", path).
					Msg("failed to delete")

				return err
			}

			return nil
		}

		return zerr.ErrCacheMiss
	}); err != nil {
		return err
	}

	return nil
}